Datron 4708 User Handbook Manual Download Page 100

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Summary of Contents for 4708

Page 1: ...USER S HANDBOOK 4708 datron I N STR LJN1 EN TS autocal multifunction standard ...

Page 2: ...1988 lue to our policy of continuously updating our products this handbook may contain minor differences in specification components and circuit design the instrument actually supplied Amendment sheets precisely matched to your serial number are available on request D 1988 Datron Instruments ...

Page 3: ... ELECTRIC SHOCK when connected to a high voltage source FRONT or REAR terminals carry the Full Input Voltage THIS CAN KILL Guard terminal is sensitive to over voltage It can damage your instrument Unless you sure safe DO NOT TOUCH the 1 i_ Hi ot Lo leads terminals DANGER 1 ...

Page 4: ...hing 3 2 FUNCTION Keys 3 3 OUTPUT RANGE Keys 3 3 OUTPUT Display and Keys 3 4 Frequency 3 6 MODE Selection Keys 3 9 I I Hi Lo Guard and Ground Terminals 3 10 Rear Panel 3 11 SECTION 4 USING THE DATRON 4708 4 1 Preliminaries 4 1 Limiting Characteristics 4 1 SAFETY 4 1 Interconnections 4 1 Typical Lead Connections 4 4 General Sequence of Operations 4 6 Display Messages 4 6 Operating Routines 4 7 DC V...

Page 5: ... Resistance Option 30 6 12 SECTION 7 SPECIFICATION VERIFICATION 7 1 Introduction 7 1 DC Voltage 7 2 DC Current 7 8 AC Voltage 7 12 AC Current 7 24 Resistance 7 26 Report Sheet RSI 7 30 APPENDICES TO SECTION 7 1 Validity Tolerance Calculation 7 Al l 2 Uncertainty and Traceability 7 A2 1 3 General Procedural Information 7 A3 1 4 Alternative Procedure for AC Millivolt Ranges 7 A4 1 5 Alternative Proc...

Page 6: ...Section 1 Introduction and a brief account of the Internal design Section 2 Physical connections and mounting getting It Installed Section 3 A brief scan of the available controls where they are and what they do Section 4 The correct procedures for making the 4708 perform foe you Section 5 How your 4708 can operate within an IEEE 488 system the device dependent codes you will need to use Section 6...

Page 7: ...y fitted provides an AC Voltage function Option 30 factory fitted adds calibration sources of DC Current AC Current and Resistance The 4708 incorporates a reference module which maintains a high accuracy specification over the ambient temperature range of 23 C lO C A high level of stability is achieved by use of super selected reference components and ultra stable gain defining resistors The Autoc...

Page 8: ...its with a facility for display ing the specified accuracy of output current The 4708 speci fications are shown in Section 6 Resistance Resolution and Accuracy By fitting Option 30 in conjunction with Option 10 the instru The maximum resolution is 7 5 digits with a facility for display ment can be used to calibrate resistance in eight decade ranges ing the specified accuracy of any output resistan...

Page 9: ...tional Facilities The available options for the 4708 are as follows Option 10 DCV function Option 20 ACV function Option 30 DC Current AC Current and Resistance functions Option 42 Rear output terminals as a factory fitted alternative to front panel terminals NB The rear output option is not recommended for best performance in calibrating high bandwidth low level instruments Option 90 Rack mountin...

Page 10: ...cision electronic divider derives an adjustable Working reference voltage between OV and 20V whose value depends on digital inputs from front panel keys and calibration memory Precision Electronic Divider In the out guard section the selected output value including calibration corrections is set into a digital comparator as a 25 bit number This is counted out by a crystal controlled binary counter...

Page 11: ...l to the de manded output voltage or current Timing data is output from the source to synchronize the actions of the AC Reference Gen erator and AC AC Comparator Voltage Controlled Amplifier VCA This has variable gain amplifying the output from the Sinewave Source and providing a buffered drive to the output circuits Its gain is determined by the measured difference between the RMS values of the s...

Page 12: ...rom the Hi and Lo terminals to the resistor The arrangement provides a calibrated 2 wire facility with external connection to the Hi and Lo terminals The Zero key shorts the Hi and Lo terminals in this case the resistance between the terminals is displayed and may be recalibrated When Q is selected from any other function the 4708 is forced into Remote Sense but this may be deselected for 2 wire o...

Page 13: ...s to the fuse and voltage selector printed circuit board Power Cable The detachable supply cable comprising two meters of 3 core PVC sheath cable permanently moulded to a fully shrouded 3 pin socket fits in the POWER INPUT plug recess and should be pushed firmly home The supply lead should be connected to a grounded outlet ensuring that the ground lead is connected Connect Black lead to Line White...

Page 14: ...arward extension Fit the two rear rack mounting ears to the rear of the cabinet with tongues facing forward In shallow cabinets it may be necessary to trim the tongue CAUTION Assistance is required to fit the 4708 into the cabinet Lift the 4708 into position in the cabinet locate the tongues in the slides and carefully slide backwards until the front ears butt up against the cabinet front Secure t...

Page 15: ... on 4600 IA_H_D_ L Address Data on AD0 AD4 8 IRD_L Read Strobe Active Low IDIGBUSON H I 5V 5k when 4708 is on 0V_6 Digital Common lADO Bi directional Address Data lADl Lines controlled by IAD2 Strobes and 14 15 IAD3 IAD4 _ IA_H_D_L Rear Output Terminals Option 42 The 4708 is fitted with either six front panel output terminals or six rear output terminals The Rear Output alternative is fitted at th...

Page 16: ...CK when connected to a high voltage source FRONT or REAR terminals carry the Full Input Voltage THIS CAN KILL Guard terminal is sensitive to over voltage It can damage your Instrument Unless you are SUro that it is SSfO to do so DO NOT TOUCH the 1 I Hi or Lo leads and terminals DANGER ...

Page 17: ...urations Front Panel Keys All user commands from front panel keys are executed through main program firmware A Key LED lit signifies that condi tions are valid for the selected operation and not merely that the key has made contact At any time the instrument status is described by the combina tion of LED states display values and display messages Generally if an invalid condition is selected an er...

Page 18: ... terminals The ON key will cause the error buzzer to sound and Error 8 to appear in the MODE FREQUENCY display OUTPUT OFF Trip Fail 5 Message Under certain abnormal conditions which might compromise safety the 4708 output will trip off accompanied by a FAIL 5 message on the MODE display Control is removed from the front panel keys If the FAIL 5 message is present there is noautomatic recovery from...

Page 19: ...the user setting the legend and decimal point on the OUTPUT display to match Full range values for voltage and current are marked above the keys Nominal values of each precision resistor for the O function are marked below the keys Voltage and current ranges are selectable as follows the actual output value being selected by use ofthe OUTPUT display t keys DC Voltage AC Voltage DC Current AC Curre...

Page 20: ...display is supplemented by legends which always indicate the correct units for the Range and Function selected Output and Display Control Each vertical pair of 1 4 keys is assigned to the display digit above it Thus the value registered on the display may be set within the range permitted by the function selected Each momentary press of the t key adds 1 to its digit pressing the 4 key subtracts 1 ...

Page 21: ...pears and the opposite sign appears as stepping continues in the same direction If the OUTPUT is ON during the sequence the change in output polarity is signalled by a change over from one polarity ON LED to the other N B If the 4708 is in Offset Mode with an offset present the display and output zeroes do not coincide It is therefore possible to have a positive sign on the display and the ON LED ...

Page 22: ...dds 1 to its digit and each key subtracts 1 If OUTPUT is ON the output frequency is also changed by the same incre ments as the display subject to the instrument interlocks Keys below decimal points are inactive Generally selection of a new range changes the frequency by a whole number of decades but ranging up from a frequency between 10Hzand30Hz orranging uptothe IMHzrange when the decade freque...

Page 23: ...voltage and frequency cannot be selected The diagram below illustrates the boundaries The lOV Range span is also shown for comparison The 4708 refuses to select any Voltage Frequency combination outside these constraints The temporary message Error 7 is displayed for approximately 1 second before reverting to the original display AC Current and Frequency AC Current is adjustable between 9 iA and 2...

Page 24: ... the five memory locations each time the 4708 is powered up FI 30Hz F2 300Hz F3 3kHz F4 30kHz F5 300kHz Details of storage and retrieval procedures are described in Section 4 SPOT F FREQUENCY MEMORY When in Calibration Mode five user selected Spot calibrated frequencies can be stored in non volatile calibration memory for each of the seven Output Ranges At these frequencies the 4708 output can be ...

Page 25: ...bration Uncertainty Rear Panel CALIBRATION INTERVAL switch While in Spec mode all primary functions of the other MODE keys are cancelled although the selected Guard and Sense connections remain The keys are reassigned to their secon dary functions Iim lim and ppm become active When Spec mode is intiated the magnitude of the specification toler ance itself determines whether ppm or is selected The ...

Page 26: ... Local and Remote Switching These terminals are located on the lower left of the Front Panel 1 and I Terminals The output from the internal power circuits is delivered to the 1 terminal I being its Return Analog Common HI and Lo Terminals These terminals provide a differential input to the amplitude sensing circuitry Remote Sensing The Remote Sense key has toggle action Successive presses alternat...

Page 27: ...le Output Connections Connections to the output terminals may be made either with leads or via a shrouded connector For Voltage outputs in local sense the two leads should be attached to the Hi and Lo terminals Various configurations of4708 load connections are detailed in Section 4 REAR PANEL Shown with alternative Rear Ouqjut terminals i n DATRON INSTRUMENTS I I 1 POWER INPUT The recessed POWER ...

Page 28: ...put Output The IEEE 488 Input Ouqjut D type socket J27 is a 24 way micro ribbon connector that is directly compatible with the IEEE 488 interface and the lEC defmed system J27 is located at the top of the rear panel outlined with the IEEE 488 address switch The pin layout and designations appear in Sections 2 and 5 IEEE 488 ADDRESS SWITCH 5 4 3 2 1 I 1 1 I I ADD _1 O 1 The 4708 may be addressed fo...

Page 29: ...hen connected to a high voltage source FRONT or REAR terminals carry the Full Input Voltage THIS CAN KILL Guard terminal is sensitive to over voltage It can damage your instrument V Unless you are sure that it is safe to do so DO NOT TOUCH the 1 I Hi or Lo leads and terminals DANGER 3 13 ...

Page 30: ...ISCONNEC TION OF THE PROTECTIVE GROUND TER MINAL MAY MAKE THE APPARATUS DAN GEROUS INTENTIONAL INTERRUPTION IS PROHIBITED THE TERMINALS MARKED WITH THE SYMBOL CARRY THE OUTPUT OF THE 4708 THESE TERMINALS AND ANY OTHER CONNECTIONS TO THE LOADUNDERTEST COULD CARRY LETHAL VOLTAGES UNDER NO CIRCUMSTANCES SHOULD USERS TOUCH ANY OF THE FRONT OR REAR PANEL TERMINALS UNLESS THEY ARE FIRST SATISFIED THAT N...

Page 31: ...as many sources as possible Always keep interconnecting leads as short as possible espe cially unscreened lengths Run leads together as twisted pairs in a common screen to reduce loop pick up area but beware of leakage problems and exces sive capacitance Where both source and load are floating connect I to ground at the source to reduce common mode voltages Lead Impedance Keep all leads as short a...

Page 32: ... leads from low capaci tance coaxial or twin axial cable To avoid mutual coupling Sense and Power leads should not run together in the same screen ii Current Above about IkHz with low output currents high lead capacitance can introduce shunt er rors To reduce these errors the leads should be kept as short as possible and be of low capacitance e DANGER THE 4708 OUTPUT CIRCUITS ARE NOT INTERNALLY CO...

Page 33: ...y noisy External common mode voltages are significant Use for measurements in the following ranges Voltage DCV lO iV ACV 90p V Frequency F IMHz Resistance IkQ R IMQ After selecting Q Remote Sense must be cancelled for 2 wire operation Select Local Sense and Local Guard Keep leads as short as possible not longer than 1 meter On lOOV lOOOV Ranges Ground the Lo line for Safety 4708 Terminals Load Ter...

Page 34: ...e selected automatically Select Local Guard Keep leads as short as possible not longer than 1 meter twisted pair is preferable NOTE Refer also to reactive load specifications in section 6 4708 Terminals Load Terminals Local Guard Local Guard Screened 2 wire Connection Use where Sensitive measurements are being made The E M environment is relatively noisy External common mode is significant Termina...

Page 35: ...mode Output not ON Error 3 Cal mode Incorrect range or function for mode Error 4 Cal mode Correction exceeds store capac ity Error 5 Offset or Requested output would have Error Mode been off scale Error 6 Cal mode Resistance exceeded Error lOOV Selected output exceeds voltage lOOOV frequency constraints Errors Select error The operation requested by the user is not possible in present machine conf...

Page 36: ...y changing RANGE the OUTPUT is switched OFF and the selected RANGE LED flashes User reselects OUTPUT ON 3 sec audible warning 4708 switches OUTPUT ON Audible reminder whilst OUTPUT ON RANGE LED flashing By use of 1 4 keys in lOOV or lOOOV range OUTPUT remains ON at previous voltage OUTPUT display shows selected High Voltage value RANGE and OUTPUT ON LEDs flash User reselects OUTPUT ON 3 sec audibl...

Page 37: ...TPUT is already switched ON in Low Voltage State when an attempt is made to select a voltage in excess of 75V RMS the 4708 safety interlocks prevent the selection Certain deliberate actions detailed below are then required by the operator to effect the selection Transfer from Low into High Voltage State by manual upranging 4708 switches OUTPUT OFF Selected RANGE LED flashes Operator reselects OUTP...

Page 38: ...when compli ance is limited to 2V Changing functions switches OUTPUT OFF Resistance Use the General Sequence At operation 3 Select Q Remote Sense LED lights as 4708 is forced into 4 wire At operation 4 If 2 wire Ohms is required press Remote Sense to deselect At operation 5 4 wire Ohms use 1 and I terminals for energizing current Measure at Hi and Lo terminals 2 wire Ohms use Hi and Lo terminals 1...

Page 39: ... a new OUTPUT RANGE also calls up its five spot frequencies ready for selection The 4708 output can be calibrated at each spot frequency thus achieving ultra high accuracy by eliminating the Flatness component By using non volatile memory these frequencies and their associated calibration constants are retained in store even when the 4708 is powered down In order to change the frequency setting of...

Page 40: ...easurement based on the measured ratio and Compensate each input to the DMM so that the linearity errors may be measured In Error mode once the gain error has been measured the 4708 automatically calculates and applies the compensating deviation to all its outputs on that range and function whilst displaying both the nominal uncompensated value of output and the compensation ratio Only if the DMM ...

Page 41: ...in excess of fuU scale The user is informed by Error 5 message on the MODE display with no change to the OUT PUT display Deselection of Error Mode Deselection clears the MODE display turns the green Error LED OFF and restores the 4708 gain factor to unity Normally the mode is deselected by repressing the Error key but it is also turned off by changing FUNCTION or RANGE Offset Mode DC Functions onl...

Page 42: ...nges 200 xV Other Ranges 2 of Full Range value Deselection of Offset Mode This clears the MODE display turns the red Offset LED OFF and reduces the 4708 offset to zero Normally the mode is de selected by repressing the Offset key but it is also turned off by changing FUNCTION or RANGE Combining Offset and Error Modes DC Functions only By combining Offset and Error modes it is possible to carry out...

Page 43: ...g Test Key again 2 During self test the instrument reset facility is not available either Instrument reading 4 r p inppm 1 1 X Input value L 106 J or r ju in 1 1 X Input value L 100 J Deselect in reverse sequence Test Sequence The Front or Rear panel terminals are not energized during Test sequence Safety and Memory Checks 1 Initial Conditions Ensure that OUTPUT OFF LED is lit Error and Spec LEDs ...

Page 44: ...EDs are not lit spuriously Press Test key Test LED lights All other LEDs unlit Displays cleared momentarily then 2 MODE Display a Initial presentation r are displayed segment by segment N B Commas are presented in the MODEdis play sequence c MODE display cleared 3 OUTPUT display a Initial presentation C OUTPUT III II II ppm Nine segments and legends are presented b Progressively all seven segment ...

Page 45: ...lay overrange digit key b FREQUENCY RANGE MODE OUTPUT RANGE FUNCTION and OUTPUT keys should cause their LEDs to light except i Reset key which is inoperative and ii Test key which aborts the test In these tests the key press operates a latch so that the display or LED remains lit until another key is pressed Only one key press at a time is recognized c To Terminate the Test Sequence Press Zero key...

Page 46: ...ry message The operation requested by the user is not possible in present machine con figuration Error 9 Option not fitted Temporary message The requested range or function option is not fitted Error EF External frequency The external frequency is not present machine will perform out of specification Error OL Voltage Ranges The output has bwn current limited by an overload If in lOOV or lOOOV rang...

Page 47: ... arrows Lit Green Store only FREQUENCY RANGE keys are reassigned to select F1 F5 memory stores Warnings with Function DC or AC Selected OUTPUT RANGE lOOV or lOOOV LED flashing A voltage in excess of llOV DC or 75V RMS AC has been selected OUTPUT ON or OFF ON LED flashing while in Low Voltage State with OUTPUT ON An attempt to select output in excess of llOV DC or 75V RMS AC has been prevented Repr...

Page 48: ...when connected to a high voltage source FRONT or REAR terminals carry the Full Input Voltage THIS CAN KILL Guard terminal is sensitive to over voltage It can damage your instrument I Unless you are sure that it is safe to do so DO NOT TOUCH the 1 I Hi or Lo leads and terminals DANGER 4 21 ...

Page 49: ...onnected to the IEEE 488 Interface Bus and set into programmed communication with other bus connected devices under the direction of a system controller Programming Options The instrument can be programmed via the IEEE Interface to 1 Change its operational state Range Function Fre quency Mode Output etc 2 Transmit its own status data to other devices on the bus 3 Request service from the system co...

Page 50: ...nd or Identify 6 DAV Data Valid 7 NRFD Not ready for Data 8 NDAC Not Data Accqpted 9 IFC Interface Clear 10 SRQ Service Request 11 ATN Attention 12 SHIELD Screening on cable connected to Safety Ground 13 DIO 5 Data Input Output Line 5 14 DIO 6 Data Input Output Line 6 15 DIO 7 Data Input Output Line 7 16 DIO 8 Data Input Output Line 8 17 REN Remote Enable 18 GND6 Gnd wire of twisted pair with DAV ...

Page 51: ... the SRQ source and that its OUTPUT is ON 7 It next addresses the DMM as a listener and sends the GET message Group Execute Trigger via the DIO lines to initiate the reading After a short delay for measurement the DMMprepares output data and SRQ s the controller when it is ready for transfer 8 The controller identifies the DMM by a serial poll Finding that the reading is available it sends the DMM...

Page 52: ...ission to the controller as a response to its subsequent serial poll Calibration Enable A Calibration Enable command via the bus is required to set the instrument into its Remote Calibration mode the CALI BRATION ENABLEkeyswitch on the rear panel must already be set at ENABLE Selection of any address 0 30 inhibits manual calibration from the front panel In remote calibration may be initiated with ...

Page 53: ...e string is discarded Device dependent commands To give maximum scope for system programming the bus operation of the 4708 differs in detail from manual operation which is organised for ease of front panel use Some functions of the 4708 firmware are deleted for bus operation as they are easily programmed into the system controller and extra func tions have been made available to take advantage of ...

Page 54: ...ates Q1 SRQ on Overload and Fall only Q2 No SR 2s Output Range RO Autorange R1 loop R2 Im KK2 R3 10m lOOa R4 loom lldl K5 1 10ki2 R6 10 lOOka R7 100 IMO R8 1000 lOMfl R9 100Mi2 Sense SO Local Sense SI Remote sense Spot TO Cancel Spot Frequency Frequencies T1 SFl T2 SF2 T3 SF3 T4 SF4 TS SFS Specification UO 24 hours Tolerance Absolute U1 90 days Output low limit to bus Limits of Uncertainty U2 1 ye...

Page 55: ...oller But see Safety Delay Override command D1 in the text In manual operation the user who is exposed to danger from high voltage also has direct control of the 4708 output but it is not possible to give the same degree of built in protection to exposed users when the instrument is under remote programming so it is ESSENTIAL that WHENEVER THE 4708 IS BEING USED IN A SYSTEM TO GENERATE VOLTAGES IN...

Page 56: ... too high the value is truncated to the correct resolution and the controller is informed by SRQ and RQS Status byte see RQS status byte formats later in this section High Voltage Outputs The change fi om Low to High voltage state is controlled by the same interlocks which govern the manual changeover Refer to Section 4 page 4 7 To effect the changeover the command string M followed by voltage 01 ...

Page 57: ...e formats later in this section Spot Frequency Selection Codes T1 T5 select the spot frequencies stored in SF1 SF5 non volatile memories Sixty unique memory locations exist Thirty five are allocated to the seven AC Voltage output ranges and twenty five to the five AC Current ranges five for each range The value of the frequeney called up by any T command is therefore dependent on the preselected F...

Page 58: ...ypical string such as the 4708 output value Notice that numerical data is reduced to a standard form and scaled by means of an exponent in base 10 All device dependent messages use the ASCII code Figure 5 4 Breakdown of a typical Output String This is a general example two specific 4708 examples appears on page 5 12 1 byte 1 byte Variable length 1 byte 1 byte 2 bytes 0or2 bytes 0or2 bytes ASCII sp...

Page 59: ...ation Tolerance Per unit P codes The P commands give access to Spec mode over the bus also setting the calibration interval P0 24 hour PI 90 day P2 1 year On being commanded by Pcode the 4708 calculates the Output Uncertainty of its current state as a per unit fraction of the output value and generates an output string formatted by K and L codes Legends are transmitted as pu per unit Absolute Limi...

Page 60: ... transmit strings without terminators To accommodate these variations the system programmer uses the K codes K0 No suppression Cr Lfand EOI all pres ent as terminators K1 Suppress EOI Terminator Cr followed byLf K2 Suppress Lf Terminator Cr with EOI K3 Suppress Lf and EOI Terminator Cr K4 Suppress Cr Terminator Lf with EOI K5 Suppress Cr and EOI Terminator Lf K6 Suppress Crand Lf Terminator EOI wi...

Page 61: ...8 and rthe RQS byte repre sents several states as listed in Table 5 5 Example with bit b6 false RQS status byte OKWOOOl represents 0 No option or Syntax error 1 This instrument originated the SRQ 0 The following bits each represent separate states 0 This bit is not used in the 4708 0 No High Voltage warning 0 Auxiliary register not at limit 0 Main register not at limit 1 Output is ON The RQS statu...

Page 62: ...er it is essential that it has been programmed by a P U V or Xcommand Otherwise it will have no data to uansmit Universal commands LLO Local Lockout ignored no capability PPU Parallel Poll Unconfigure ignored no capability for parallel poll SPE Serial Poll Enable sets the 4708 to serial poll state which when addressed responds with the RQS status byte This byte contains the condition of the reques...

Page 63: ... must be already programmed to prepare data DAB Data bytes sent by currently enabled talkers to all currently enabled listeners DAB UNT Disables the talker on receipt of the last character pUNL unlisten LAD listen address of specific device TAD talk address of specific device DAB data bytes Lunt untalk Untalk It is highly desirable that a sequence which causes a device to be addressed as a talker ...

Page 64: ... when connected to a high voltage source FRONT or REAR terminals carry the Full Input Voltage THIS CAN KILL Guard terminal is sensitive to over voltage It can damage your instrument Unless you are SUre that it is safe to do so DO NOT TOUCH the 1 I HI or Lo l6dds and terminals DANGER 5 16 ...

Page 65: ...s MECHANICAL OPERATING INDICATIONS Dimensions Height 178mm 7 Width 455mm 17 9 Indication Symbols lit on displays and Depth 564mm 22 2 illuminated keys Weight 36kg 801b Scale Lengths SAFETY The 4708 has been designed to Output Display 7 5 digits maximum meet BSI 4743 lEC 348 and Frequency Display 3 digits plus store location UL 1244 specifications Mode Display 7 5 digits maximum PEAK TERMINAL VOLTA...

Page 66: ...Period pk pk Average Over 1 0 Line Periods pk pk DC 2HZ Typical Null Detector pk pk lOOpV IOOmV 4pV 0 2pV 0 5pV 0 1 pV IV 4pV 2pV 0 5pV 0 5pV 10V lOpV 5pV 2pV 2pV 100V 120pV 50pV 25pV 25pV 1000V 2 5mV 600pV 200pV 150pV Notes 1 For same conditions between 18 C and 28 C 2 FS 2 X Range 3 For lOkHz wide band multiply 2 5kHz figures by 2 For RMS divide pk to pk figures by 6 Other Specifications Output ...

Page 67: ...CK when connected to a high voltage source FRONT or REAR terminals carry the Full Input Voltage THIS CAN KILL Guard terminal is sensitive to over voltage It can damage your instrument Unless you are SUrG that it is safG to do so DO NOT TOUCH the 1 I Hi or Lo leads and terminals DANGER ...

Page 68: ...0k 20 2 70 10 90 10 100 10 10k 33k 30 2 110 10 130 10 140 10 750V Max 30k 100k 50 10 500 20 750 20 1000 20 Notes 1 For same conditions between 18 C and 28 C 2 FS 2 X Nominal Range 3 Estimated not fully traceable 4 Figures Indicate pure THD only excluding noise which is included in the main specifications THD is predominantly second harmonic negligible error on mean sensing equipment 5 For Frequenc...

Page 69: ...1000 20 3 0 1 Typically 80 20 3 0 04 0 002 FS 30 20 3 0 04 to 33kHz 120mA 30 20 3 0 04 increasing to 40 50 5 0 2 0 02 FS at 100kHz 2 60 200 3 20 0 3 200 30 5 0 2 Typically 3 3kHz 15mA 130 30 5 0 1 0 002 FS 2 3 0kHz 65mA 90 50 5 0 1 120 50 7 0 5 200 Other Specifications Scale Length Voltage Sensing Guarding Common Mode Rejection Settling Time 5 Frequency Accuracy Maximum Load Capacitance 9 to 200 o...

Page 70: ......

Page 71: ...Capacitive Loading Constraints volt Hertz Power Limit versus Capacitance Load 1 kV Range Volt Hertz 3 X 10 100 200 300 400 600 800 1000 Total Load Capacitance Including Leads pF ...

Page 72: ...0 00000mA 3 4 5 5 20 5 40 5 9 6 200Mn 3V 100 0000mA 3 4 5 5 20 5 40 5 9 6 20MQ 3V 1 000000A 3 7 10 10 10 50 10 100 10 21 15 1MQ 3V Noise Range 2 5kHz RMS Average Over 1 Line Period pk to pk Average Over 10 Line Periods pk to pk lOOjiA 5nA 6nA 2nA 1mA 5nA 6nA 2nA 10mA 50nA 30nA 20nA 100mA IjiA 500nA 400nA 1A 25pA 30pA 20pA Notes 1 For same conditions between 18 C and 28 C 2 FS 2 X Range 3 Typical a...

Page 73: ...CK when connected to a high voltage source FRONT or REAR terminals carry the Full Input Voltage THIS CAN KILL Guard terminal is sensitive to over voltage It can damage your instrument Unless you are SUfG that it is SafG to do so DO NOT TOUCH the 1 I Hi or Lo iGGds and tGrminals DANGER ...

Page 74: ... transfer up or down between the undermentioned frequencies must be regarded as a frequency range change Settling Time should be allowed as for Other Specifications 31 32 Hz 300 301 Hz 3 00 3 01Hz For settling to lOppm of Step Size multiply all times by 1 5 6 Assumes similar load time constant to that at calibration 7 Specifications valid for compliance 0 5Vrms For 0 5Vrms add the following lOOpA ...

Page 75: ... 10 0 2 300kn 3Vrms 100 10 0 2 100 20 0 2 30kn 3Vrms 100 25 1 0 Typical effective output capacitance 200pF Typical effective output capacitance O Sj F Negligible on other ranges Other Specifications Scale Length Settling Time 5 Frequency Accuracy Maximum Load Capacitance Maximum Load Inductance Sense 9 to 200 of range all ranges To lOOppm of step size double for range changes 10 32Hz 10s 32 330Hz ...

Page 76: ...X 10 F lO OOOOOOk 1 1 5 3 9 4 2 lOOpA 2 5mA 8 5 X 10 F 100 00000k 1 1 5 3 10 6 2 lOOpA 1mA 8 5 X 10 F 1 0000000M 2 4 10 25 12 6 lOpA lOOpA lOx 10 F 10 000000M 2 10 25 50 17 10 IpA lOpA 15x 10 P 100 00000M 3 15 30 70 50 20 IpA lOpA 15x 10 F For 2 Wire Sensing 24 hours stability 24 hours accuracy 90 days accuracy add 0 1 Q 1 years accuracy add 0 2Q Notes 1 Range figures are nominal actual calibrated...

Page 77: ...CK when connected to a high voltage source FRONT or REAR terminals carry the Full Input Voltage THIS CAN KILL Guard terminal is sensitive to over voltage It can damage your instrument Unless you are sure that it is safe to do so DO NOT TOUCH the 1 I Hi or Lo leads and terminals DANGER ...

Page 78: ...ty is verified at IV lOV and 19V on the lOV range at LF using the same method 4 AC Millivolt Ranges ImV to lOOmV Full Range values are verified as follows a At LF Commercially available Inductive Voltage Divider and standardized DVM transfer Such IVD s are normally only suitable for LF verification up to about 5kHz b At HF A 100 to 10 of Range Transfer method after verifying lOV range HF linearity...

Page 79: ... and basic and are mainly intended to show connec tions to the 4708 It is recognized that they may need to be adapted to meet an individual user s requirements It is assumed that users will possess knowledge of the operation and use ofstandards equipment such as that mentioned above Equipment Requirements A Standard DC Voltage Source of suitable accuracy Example Series bank of 10 standard cells an...

Page 80: ...RNING THE TERMINALS MARKED WITH THE SYMBOL CARRY THE OUTPUT OF THE 4708 THESE TERMINALS AND ANY OTHER CONNECTIONS TO THE LOAD UNDER TEST COULD CARRY LETHAL VOLTAGES UNDER NO CIRCUMSTANCES SHOULD USERS TOUCH ANY OF THE FRONT OR REAR PANEL TERMINALS UNLESS THEY ARE FIRST SATISFIED THAT NO DANGER OUS VOLTAGE IS PRESENT 7 3 ...

Page 81: ...give an off null reading j DC Voltage Standard Adjust output voltage to give a null on the Null Detector k Repeat h and j until the null lies between two consecutive values of DC Voltage Standard Output at the same resolution as the 4708 OUTPUT display l DC Voltage Standard Record output voltage on RSI m Repeat e to 1 for all 4708 outputs on RSI Table 1 a n DC Voltage Standard Set OUTPUT OFF p 470...

Page 82: ...R REAR PANEL TERMINALS UNLESS THEY ARE FIRST SATISFIED THAT NO DAN GEROUS VOLTAGE IS PRESENT Note On the diagram the terminals of the Precision Divider are marked PHI PLO SHI and SLO These are terms which apply to the Datron 4902 and 4902S referring to their Power Hi Lo inputs and Sense Hi Lo pickoffs for true 4 wire connections described in their User s Handbook For other dividers it is important...

Page 83: ...e see page 4 7 iii Press the correct polarity OUTPUT ON key g DC Voltage Standard Set OUTPUT ON h Null Detector Increase sensitivity to give an off null reading j DC Voltage Standard Adjust output voltage to give a null on the Null Detector k Repeat h and j until the null lies between two consecutive values of DC Voltage Standard output at the same resolution as the 4708 OUTPUT display l DC Voltag...

Page 84: ...ents A DC Voltage Source calibrated to suitable accuracy at IV and lOOmV Example The verified DC Voltage ranges of the instrument under test A set of Calibrated Current Shunts of suitable accuracy A DMM of sufficient resolution and stability to measure the voltage across the set of shunts Example A Datron 1281 1081 1071 or 1061 A used as a transfer measurement device N B To allow the same value to...

Page 85: ...been recently calibrated or that its zero offsets have been removed and its polarity turnover at IV lOOmV is verified as accurate Standardize the DMM before verifying the ranges in the sequence of RS 1 Table 2 a 4708 Set OUTPUT OFF FUNCTION to DC OUTPUT RANGE to 1 100m Sense and Guard to Remote OUTPUT Display to 1 0000000 V 100 00000mV b Connect the DMM to read the 4708 output for standardization ...

Page 86: ...rdization of the DMM items a to g but at lOOmV m Repeat h and j but for 4708 1A Full Range output using the O IQ transfer shunt n Sum the Verification setup uncertainties and record in the Us column as current deviations Refer to Appendix 2 Validity Tolerance Limit Calculations Refer to Appendix 1 page7 Al l p Calculate the Lower and Upper Validity Tolerance Limits Use Calculation A if the 4708 wa...

Page 87: ... when connected to a high voltage source r FRONT or REAR terminals carry the Full Input Voltage THIS CAN KILL Guard terminal is sensitive to over voltage It can damage your instrument I Unless you are sure that it is safe to do so DO NOT TOUCH the 1 I Hi or Lo leads and terminals DANGER ...

Page 88: ...pted to meet an individual user s requirements It is assumed that users will possess knowledge of the operation and use ofstandards equipment such as that mentioned above Equipment Requirements An adjustable DC Voltage Source of suitable accuracy Example Datron 4000 or 4000A Autocal Standard An AC DC Thermal Transfer Standard capable of operating over the range IV to 1 lOOV RMS Preparation Before ...

Page 89: ...TAGES UNDER NO CIRCUMSTANCES SHOULD USERS TOUCH ANY OF THE FRONT OR REAR PANEL TERMINALS UNLESS THEY ARE FIRST SATISFIED THAT NO DAN GEROUS VOLTAGE IS PRESENT Note For the arrangement shown in the diagram the coaxial T connector provides true 4 wire connection to the AC coaxial input of the Thermal Transfer For Thermal Transfers with other AC terminations it is important that true 4 wire connectio...

Page 90: ...r Record its output voltage on RSI h Repeat c to g for all 4708 outputs on RS 1 Tables 1 a and 1 b j Sum the Verification setup uncertainties and record in the Us column as voltage deviations Refer to Appendix 2 For Validity Tolerance Limit Calculations Refer to Appendix 1 page 7 Al l para 1 k Calculate the Lower and Upper Validity Tolerance Limits Use Calculation A if the 4708 was last calibrated...

Page 91: ... for the procedure Interconnections Interconnection instructions in this section arc necessarily simple and basic and are mainly intended to show connec tions to the 4708 It is recognized that they may need to be adapted to meet an individual user s requirements It is assumed that users will possess knowledge of the operation and use ofstandards equipment such as lhatmentioned above Equipment Requ...

Page 92: ...0mV at 1kHz r AC DVM mV RANGES A 4708 AC IV RANGE s Ouar Kct 05 DANGER HIGH VOLTAGE 19 5mm shorting link Fig 1 Standardization of DMM a With OUTPUT OFF connect the 4708 IVD and DMM for Standardization Fig 1 Set the IVD ratio to 1 10 the AC DMM to measure lOOmV b Set 4708 to IV Range IkHz and adjust 4708 output to value measured in RS 1 table 3 a c Set 4708 OUTPUT ON and note the DMM reading as vr ...

Page 93: ...d IV Full Range output at step b Record the results on RSI Table 4 a j Sum the Verification setup uncertainties and record in the Us column as voltage deviations Refer to Appendix 2 Validity Tolerance Limit Calculations Refer to Appendix 1 page 7 Al l para 1 k Calculate the Lower and Upper Validity Tolerance Limits Use Calculation A if the 4708 was last calibrated by Datron Use Calculation B if th...

Page 94: ...arity error at IV on the lOV Range From the linearity measurement a T0 of Range Linearity and Scaling Factor C is derived This factor is subsequently used to correct the 4708 output setting at 10 of range to standardize a DVM for verification of the next range down Interconnections FIG 1 10V and IV Ranges 4708 All outputs 1MH2 Rsmots Sons and Local Gkjard FIG 2 lOOmV to ImV Ranges 4708 DMM lOOmV R...

Page 95: ...measure AC on its IV Range d On 4708 select the IV Range and Remote Sense Set FREQUENCY to IMHz OUTPUT Display reading to V3 OUTPUT ON and note the DVM reading as Vf OUTPUT OFF e On 4708 select the lOV Range Remote Sense Set 4708 OUTPUT Display reading to IV Set OUTPUT ON Adjust the OUTPUT Display for a DVM reading of Vt f Note the 4708 OUTPUT Display reading as V4 Set OUTPUT OFF g From the values...

Page 96: ...V lOOm Record this setting in the last column of RSI table 4 b Calculate in 6 5 digits resolution V3xC V lOOt is a transfer value V lOOt Record in 6 5 digits resolution V lOOm Stage 3 To Verify the lOmV Range Full Range Output a Ensure that the DMM is still connected to the 4708 terminals as shown in Fig 2 b Ensure that the 4708 is set to the 100mV Range Calculate the value V lOOm x C Set the OUTP...

Page 97: ...5 Verification Against Limits For Validity Tolerance Limit Calculations Refer to Appendix 1 page 7 Al l para 1 a Sum the Verification setup uncertainties and record in the Us column of RSI table 2 b as voltage deviations Refer to Appendix 2 b Calculate the Lower and Upper Validity Tolerance Limits Use Calculation A if the 4708 was last calibrated by Datron Use Calculation B if the 4708 was last ca...

Page 98: ... 1 i I 1 1 J 7 23 ...

Page 99: ...an individual user s requirements It is assumed that users will possess knowledge of the operation and use ofstandards equipment such as that mentioned above Equipment Requirements A DC Current Source of suitable accuracy and an AC DC Thermal Transfer together with a set of Calibrated Thermal Transfer Current Shunts of suitable accuracy For the alternative method at Appendix 5 a set of calibrated ...

Page 100: ...the Transfer switch to DC f Set the DC Standard OUTPUT ON and adjust its output current to null the Thermal Transfer Set its OUTPUT OFF Record its output current on RSI Table 5 a g Set 4708 Frequency to 5kHz and repeat c to f h Repeat a to g but for 4708 100mA and lA Full Range outputs j If the Thermal Transfer has been adequately calibrated for 1mA transfers repeat a to g for 4708 1mA Full Range ...

Page 101: ...n instructions in this section are necessarily simple and basic and are mainly intended to show connec tions to the 4708 It is recognized that they may need to be adapted to meet an individual user s requirements It is assumed that users will possess knowledge of the operation and use ofstandards equipment such as ihatmentioned above Equipment Requirements A DMM of sufficient accuracy used to meas...

Page 102: ...b Connect the DMM as shown in the above diagram for direct 4 wire measurement of the value of the internal resistor only c 4707 i Press the designated resistor RANGE key The previously calibrated value appears on the OUTPUT display i i Record on Table 6 a as OUTPUT Display Reading Rd e DMM i Measure the value of the internal resistor i i Record on Table 6 a as Measured Value Qm f 4708 Set OUTPUT O...

Page 103: ...the above diagram for a 4 wire measurement of the internal resistance between the Hi and Lo terminals c 4708 i Press required resistor RANGE key ii Press OUTPUT ON d DMM i Measure the value of the resistance between the Hi and Lo terminals i i Record on RS 1 Table 6 b as 2 Wire Value Om 2 i Enter the 4 Wire Measured Values Om from Table 6 a into their respective columns of Table 6 b as 4 Wire Valu...

Page 104: ...7 29 ...

Page 105: ... continuous trace of all the uncertain ties from the instrument terminals via Absolute Accuracy to the measuring equipment connections to those terminals The validity tolerance of the trace is obtained by adding together all the intervening uncertainties at the time the measurement is made The specification sets out the worst case allowances relative tolerances for the instru ment performance For ...

Page 106: ...Ud Abs Us Abs Upper Limit Ur Ud Abs Us Abs Performed on 10V Range 4708 Relative Accuracy Datron User s Validity Tolerance Limits User s POLARITY Tolerance Limits Cal Std Cal Std DC Standard NOMINAL Uncerfy Uncerfy value for VALUE Lower Lr Upper Ur Ud Abs Us Abs Lower Upper Null OV 0 000003V 0 000003V OOOOOOV OV 0 000003V 0 000003V OOOOOOV IV 0 999996V 1 000004V 000002V IV 1 000004V 0 999996V 00000...

Page 107: ...oltage Relative Toleranc Accuracy e Limits Datron Cal Std Uncerfy User s Cal Std Uncert y Calculat Toleranc ed Total e Limits OUTPUT Display Reading tOOpA 99 9930 100 0070 0 0009 iA IOOmA 100 0070 99 9930 0 0009uA 1mA 999970 1 000030 000009mA 1mA 1 000030 999970 000009mA 10mA 9 99970 10 00030 0 00009mA 10mA 10 00030 9 99970 H 100mA 99 9970 100 0030 0 0009mA 100 0030 99 9970 4 1A 999930 1 000070 00...

Page 108: ...50 0 050V b Linearity Performed on 10V Range 10V 1kHz 1 00000V 0 99987 1 00013 0 00002V 10V 1kHz 10 00000V 9 99960 10 00040 0 00020V 10V 1kHz 19 00000V 18 00933 19 00067 0 00038V 4 AC MILUVOLTS ImV to 100mV Ranges 4708 4708 Wideband Datron User s Validity Tolerance Limits 4708 OUTPUT Nominal RelativeAccuracy Cal Std Cal Std OUTPUT RANGE OUTPUT Tolerance Limits Uncert y Uncert y Display FREQUENCY V...

Page 109: ... Us Abs must include the relative uncertainties of the DC Voltage Source Transfer Shunt and Thermal Transfer a 10mA to 1A Ranges Using Thermal Transfer Current Shunts and DC Current Standard 10mA 300Hz 9 99870 10 00130 0 00100mA 10mA 5kHz 9 99820 10 00180 0 00100mA 100mA 300Hz 99 9870 100 0130 0 0100mA 1 00mA 5kHz 99 9820 100 0180 0 0100mA 1A 300Hz 999690 1 000310 000100A 1A 5kHz 999520 1 000480 0...

Page 110: ...y Ut ppm Validity Tolerar Lower Limit ce Upper Limit Measured Value lOOMa 30 50 10MQ 25 17 1M 1 10 12 looka 3 6 lokn 3 4 IkQ 3 5 looa 3 5 IQ 30 b 2 Wire Local Connection The additional resistance of the internal 2 wire connections should not exceed the following 10Q to 1MI2 Ranges 1 999a At Zero on the lOa to 1 Ma Ranges 0 900a Thus the measured 2 wire resistance values should lie between Rd and t...

Page 111: ...uency selection calcu late the Validity Tolerance Limits as follows Lower Limit Lr Us Upper Limit Ur Us Enter the results as Lower and Upper Validity Tolerance Limits respectively 2 Post Calibration Verification Calculation using the instrument Spec Mode ppm or Readout This calculation can be used to verify the instrument after calibration with the CALIBRATION INTERVAL switch on the rear panel set...

Page 112: ...s The 4707 is verified by comparing its output with the Validity Total Tolerance Limits These are calculated by summing the appropriate uncertainties from the traceability chain and expressing the result in upper and lower absolute deviations from the chosen verification value The 4708 checks out if its measured output is between the limits Where possible the 4708 specification and Datron calibra ...

Page 113: ...FR Linearity DC Voltage DC Current DCVto ACV Thermal Transfer Standard 4708 DC Current Cal 0 1mA 1A Rarrges ZeroA FR DC CurrerH DC Current 4708 AC Voltage Cal IV 1000V Ranges FR A Linearity AC Voltage AC Volt e Ratios Therrrtal Transfer Current Shunts DCFACI Transfer Calibration Inductive Divider AC Millivolts Calibration Standardization of DVM AC IV AC Current Conversion Calibration Starvjardizat...

Page 114: ... source without first switching the 4708 OUTPUT OFF Care must be taken to ensure that the correct polarity ON key is pressed to avoid excessive voltages being connected across the null detector particularly when checking the 4708 directly against a standard cell 4 Most Null Detectors are equipped with a Self zero or Zero check facility For maximum accuracy the Null Detector range zero should be ch...

Page 115: ...terminals Such voltages may be present during the time that the 4708 is ramping from zero to 1 lOOV Full Scale after setting OUTPUT ON Notes on the 4708 1 Local Remote Sense Remote Sense is available as follows IV lOV lOOV lOOOV Local Remote Sense ImV lOmV lOOmV Local Sense only All Current Ranges not applicable Local Remote Sense LED OFF 2 Wire Sense Remote Remote Sense LED ON 4 Wire Sense OUTPUT...

Page 116: ...Spec Mode To obtain the value entered when a resistor was calibrated in 4 wire it is necessary for the key LED to be lit but for 2 wire it must be unlit When values are entered during calibration the 2 wire figures are the results of 4 Wire measurements at the Hi and Lo terminals NOT the 1 and I terminals Verification check figures are therefore only valid if they are obtained from measurements un...

Page 117: ...ions The 24 hour stability specifications are relative to user s reference standards In all cases validity depends on using the same standard as reference under the same condi tions including temperature Also verification is valid only within 24 hours ofcalibration or within 24 hours ofa previous verification In the latter case the specifications are relative to the figures obtained at the earlier...

Page 118: ...ainly intended to show connec tions to the 4708 It is recognized that they may need to be adapted to meet an individual user s requirements It is assumed that users will possess knowledge of the operation and use ofstandards equipment such as that mentioned above Preparation Before attempting any verification ensure that the follow ing steps have been carried out 1 Turn on the instrument to be che...

Page 119: ...Range Checks 1mV 100mV LF 1kHz and HF 100kHz WIDEBAND INDUCTIVE VOLTAGE DIVIDER 4708 AC 1V RANGE a With OUTPUT OFF connect the 4708 WIVD and DMM for Standardization Fig 1 Set the WIVD ratio to 1 1000 the AC DMM to measure ImV b Set 4708 to IV Range IkHz and adjust for corrected 1 0000 X V output c Set 4708 OUTPUT ON Note the DMM reading as VI d Set 4708 OUTPUT OFF 7 A4 2 ...

Page 120: ...lOOmV Full Range outputs still using the corrected IV Full Range output in b Record the results on RS2 k Sum the Verification setup uncertainties and record in the Us column as voltage deviations Refer to Appendix 2 Total Tolerance Limit Calculations Refer to Appendix 1 page 7 Al l para 1 l Calculate the Lower and Upper Total Tolerance Limits Use Calculation A if the 4708 was last calibrated by Da...

Page 121: ...e Lower Limit Lr Ud Abs Us Abs Upper Limit Ur Ud Abs Us Abs 4708 4708 Wideband Datron User s Validity Tolerance Limits 4708 OUTPUT Nominal RelativeAccuracy Cal Std Cal Std OUTPUT RANGE OUTPUT Tolerance Limits Unceify Unceify Display FREQUENCY Voltage Lower Lr Upper Ur Ud Abs Us Abs Lower Upper Setting 1mV 1kHz I OOOOmV 9950 1 0050 0 00 lOmV ImV 100kHz I OOOOmV 9947 1 0053 0 0013mV lOmV 1kHz 1 0 00...

Page 122: ... to be adapted to meet an individual user s requirements It is assumed that users will possess knowledge of the operation and use ofstandards equipment such as that mentioned above Equipment Requirements A set of calibrated AC Current Shunts of suitable value and accuracy A buffer with unity gain verified at 300Hz and 5kHz A DMM of suitable accuracy Example Datron 1281 or 1081 in Compute Mode Prep...

Page 123: ... Standardization of DMM 1V Range a Set the 4708 Frequency to 300Hz b With OUTPUT OFF connect the 4708 and DMM for Standardization Select IV Range on the AC DMM c Set the 4708 to its IV Range and adjust for corrected l OOOOOOV output as verified d Set 4708 OUTPUT ON and note the DMM reading as VI e Set 4708 OUTPUT OFF Set its OUTPUT RANGE to 100 xA and adjust the OUTPUT Display to lOO OOOOttA 7 A5 ...

Page 124: ...Repeat a to I for the four other 4708 Current Ranges on RS3 using appropriate shunts n Sum the Verification setup uncertainties and record in the Us column of RS3 as current deviations Refer to Appendix 2 Validity Tolerance Limit Calculations Refer to Appendix 1 page 7 Al l Para 1 p Calculate the Lower and Upper Validity Tolerance Limits Use Calculation A if the 4708 was last calibrated by Datron ...

Page 125: ...ge Checks Validity Tolerance Lower Limit Lr Ud Abs Us Abs Upper Limit Ur Ud Abs Us Abs Us Abs must include the uncertainties of the DMM Buffer and Transfer Shunt 4708 OUTPUT RANGE FREQUENCY Measured Shunt Voltage Widet Relative Toleranc Lower Lr and curacy e Limits Upper Ur Datron Cal Std Unceity Ud Abs User s Cal Std Uncerfy Us Abs Validity T Lift Lower olerance its Upper Calculated Current lOOpA...

Page 126: ...n particularly at low fundamental levels where the harmonic envelope rapidly descends into the noise floor Measurement of true harmonic distortion only in any signal can be a lalxMious process To measure the value of each single frequency htumonic as would be required to verify the 4708 THD specification any wideband noise must be filtered ouL Very selective bandpass notch filtering is re quired t...

Page 127: ...CK when connected to a high voltage source FRONT or REAR terminals carry the Full Input Voltage THIS CAN KILL Guard terminal is sensitive to over voltage It can damage your instrument Unless you are sure that it is safe to do so DO NOT TOUCH the 1 I Hi or Lo leads and terminals DANGER ...

Page 128: ...the updated factors are continuously applied to correct the 4708 output amplitude Special keys are used in the Autocal mode They are illustrated below h m lim ppm HHI Guard Sense Spec Error Offset Test STD SET 0 CAL The threee keys labelled STD SET and 0 preselect alternative calibration modes To finally implement any calibration the CAL key must be pressed STD SET and 0 have press on off action T...

Page 129: ... key The 0 key is used to align the ON h and ON zeros of all voltage and current ranges by a 2 part calibration on the lOV range The 0 Alignment Routine on Page 8 6 is necessary only when the ON and ON zeros on the lOV range do not co incide at the same null CAL Key The CAL key executes the preselected Autocal facility as described in SET above Alterna tively it can be used without first pressing ...

Page 130: ...alue to be set on the DC Voltage source for each range the shunts may be of five decade values Then the same Null Detector sensitivity can be used on each range CAUTION When choosing a set ofcurrent shunts ensure that their power dissipation ratings are sufficient to avoid permanent degradation from the self heat ing effects of the current being checked This applies particularly to the 1 Amp shunL...

Page 131: ...n Source voltage is set to zero and that the inter connecting circuit has thermally stabilized 3 CALIBRATION ENABLE key switch Insert Calibration Key and turn to ENABLE CALIBRATION ENABLE RUN These actions activate the four calibration modes labeled in red and present the caT legend on the MODE display 4 Ensure that OUTPUT OFF LED is lit Return to use When any calibration is completed re turn the ...

Page 132: ... and value Select correct FUNCTION and RANGE Use Full Range Zero or OUT PUT 1 4 keys to set the required polarity and value on OUTPUT display N B Operation 0 must be carried out before operation g f 4708 Press the correct polarity ON key 0 Alignment Routing Alignment of lOV Range positive and negative zeros if neces sary at step 3 of Table 8 2 a Null Detector Set to low sensitivity b 4708 Ensure O...

Page 133: ... 1 b Calibration Precision Stop Calibration Operation 4708 Range Source Divider 708 Output Sotting AUTOCAL Key Voltage Select Nominal Value Used 100V Range gain 100 1000V Range Zero 1000 1000V Range gain LETHAL VOLTAGE 1000 ON SET for 100 00000V non nominal ON O OOOOV ON 1000 0000V SET for 100 Enter High Voltage state using Interlock procedure User s Handbook Sect 4 non nominal NOTES 1 It is expec...

Page 134: ... Routing at each step Table 8 3 STEPS In DC CURRENT CALIBRATION step Calibration Operation Shunt Value Calibration Source Voltage 4708 Output Current AUTOCAL K y Us d Range 1 OUTPUT Setting 1 lOO iA Range zero 10kU OOOOOOOV 00 l O OOOO A 2 lOOnA Range gain 10W1 1 0000000V lOOn 100 0000 A SET for non nomina 3 1mA Range zero IkO OOOOOOOV 1m OOOOOOmA 4 1mA Range gain ikn 1 OOOOOOOV 1m 1 OOOOOOmA SET ...

Page 135: ...e adjustment of the resistor is not neces sary During calibration the actual value is measured and stored in the calibration memory to be displayed whenever that range is selected Separate memory stores exist for Remote Sense 4 wire Local Sense 2 wire and Local Sense zero 2 4 Wire Calibration Limits The value measured in 4 wire Remote Sense does not include the resistance of internal or external w...

Page 136: ... for connections in Remote Sense Fig 8 3 a only the value of the internal Standard Resistor is measured In Local Sense Fig 8 3 b a 4 wire method is used to exclude the resistance ofthe external leads from the measured value 7 Calibration Routine Measurement and Storage of the values of an internal resistor a Remote Sense Internal 4 wire connected as Fig 8 3 a Full Range values Routine for Table 8 ...

Page 137: ... digits AC Calibration Wideband Calibration When CALis pressed withoutpreselecting SET 0 or STD the 4708 makes the assumption that each OUTPUT Range is to be calibrated at the exact Full Range value at either LF or HF or both This allows two correction values to be stored for each output range From their difference the microprocessor calculates a compensation factor which affects the corrections a...

Page 138: ...cluded as there are several different models each with its own methods of connection and proce dures Instead it is assumed that users will be able to operate their own equipment correctly according to the manufacturer s instruc tions The procedures which follow therefore concentrate on the operation of the 4708 during calibration accepting that the required thermal transfer will be set up to a DC ...

Page 139: ...ularly if the initial errors are large or the calibration takes longer than required by the Transfer System in use Repeat procedure as required 1000V Range Calibration Sequence LF calibration must be completed first However HF1 HF2 bands may if the user requires be calibrated in reverse order SET mode must be used for 700V HF2 SPOT Memory Erasure To prevent unwanted calibrations at obsolete spot f...

Page 140: ...Nominal Full Range merely press the Full Range key Set 4708 OUTPUT ON and if NOT at Nominal Full Range Select SET f Use the OUTPUT t keys to adjust the OUTPUT Display reading to obtain a null on the Thermal Trans fer g Execute the calibration by pressing the CAL key Nominal Cal Points for IV to lOOOV Ranges DC Standard OUTPUT Voltage 4708 OUTPUT RANGE FREQUENCY 4708 Nominal OUTPUT Voltage Freq Ban...

Page 141: ... Use OUTPUT 4 1 keys to display the required IVD input voltage if at Nominal Full range merely press the Full range key e Set OUTPUT ON note DVM reading as VI f Set OUTPUT OFF and reconnect the circuit for Calibration g Select the required Millivolt OUTPUT RANGE h Use OUTPUT 4 1 keys to display the Cal Voltage on the OUTPUT Display if at Nominal Full range merely press the Full range key j Set 470...

Page 142: ...required HF calibration points It is also assumed that the Millivolt LF Calibration has been completed Interconnections FIG 1 10V and IV Ranges FIG 2 lOOmV to ImV Ranges Stage 1 Derive the Linearity and Scaling Factor C as follows C is a number of value close to 0 1 a Ensure that the Millivolts LF Calibration has been completed Ensure that the 4708 has been calibrated and verified at AC lOV and IV...

Page 143: ...CAL pushbutton and observe the DVM reading h Repeat operation g until the post CAL DVMreading is within l iVofV 100t Ifcalibrating a Spot Frequency re press the SPOT key to deselect Stage 3 To Calibrate the AC 10mV Range Full Range Output a Ensure that the DVM is still connected to the 4708 terminals as shown in Fig 2 Reselect the Spot Fre quency if required b Ensure that the 4708 is set to the AC...

Page 144: ... c Set the DVM to measure ImV d Allow the ou ut to settle Note the DVM reading as V lt e Set 4708 to its ImV range f Adjust the 4708 Output to give a settled DVMreading of V lt Press the CAL pushbutton and observe the DVM reading g Repeat operation 0 until the post CAL DVMreading is within IpV of V lt Calculate in 5 5 digits resolution lOmV X C V lt is a transfer value V lt Stage 5 Calibration Dis...

Page 145: ...rminals across the Shunt b On ACI FUNCTION select the required OUTPUT RANGE c Select the required FREQUENCY RANGE d Use FREQUENCY 4 1 keys to display the required Cal Frequency e Use OUTPUT 4 1 keys to display the required Cal Current if at Nominal Full Range press the Full Range key f Set 4708 OUTPUT ON and if NOT at Nominal Full Range Select SET g Use the OUTPUT 4 1 keys to adjust the OUTPUT dis...

Page 146: ...t for Calibration using the correct shunt for the range to be calibrated d On ACI Function select the required OUTPUT RANGE e Select the required FREQUENCY RANGE f Use FREQUENCY keys to display the required Cal Frequency g Use OUTPUT t keys to display the required Cal Current if at Nominal Full Range press the Full Range key h Set 4708 OUTPUT ON and if NOT AT Nominal Full Range Select SET j Use th...

Page 147: ...BRAZIL Comercial Goncalves Rua Deocleciana 77 Cep 01106 Ponte Pequena Sao Paulo SP 11 2294044 22104 34272 CHINA Tianjin Zhong Huan Scientific Instruments Corp No 59 2 ao Jia Chang Street Tianjin Hong Qiao Section Tianjin 251941 DENMARK Instrutek A S Christiansholmsgade 8700 Horsens 5 611100 61656 5 615 658 EASTERN EUROPE Amtest Associates Ltd Amtest House 75 79 Guildford Street Chertsey Surrey KT1...

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Page 150: ...Bypass Indianapolis Indiana 46203 317 787 3915 TWX 810 341 3226 317 788 5999 Wavetek Northeast Area Sales 1 Executive Blvd Suite 206 SuffemNew York 10901 914 357 5544 914 357 5609 Wavetek Western Area Sales 9045 Balboa Avenue San Diego California 92123 619 565 9234 TWX 910 335 2007 619 565 9558 For customers In countries not listed please contact DATRON INSTRUMENTS In the United Kingdom Datron Ins...

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