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2-1

Chapter 2

Theory of Operation

Introduction

The Calibrator’s power supply, electronics, pneumatics, and sensor combine to form a

complete, stand-alone, measure and control instrument. This section of the manual

describes the Calibrator’s component modules and provides a general discussion of each.

The RUSKA 7252 has two pneumatic control and two primary transducer modules.

DIGITAL

CONTROL

BOARD 2

BACKPLANE

BOARD

POWER

SUPPLY

MICROPROCESSOR

BOARD

IEEE

CARD

FRONT

PANEL

POWER

PNEUMATICS

Reference Port
Test Port
Supply Pressure Port
Exhaust Port

Pneumatics Module 1

CASE

TUBE

Photo

Sensor

Primary Transducer Module 1

INNER LOOP

SENSOR

Electronic Module

PNEUMATICS

Reference Port
Test Port
Supply Pressure Port
Exhaust Port

Pneumatics Module 2

SENSOR

BOARD

SENSOR

BOARD

CASE

TUBE

Photo

Sensor

Primary Transducer Module 2

INNER LOOP

SENSOR

DIGITAL

CONTROL

BOARD 1

IEEE-488

RS-232

glb02.eps

Figure 2-1. Calibrator Block Diagram

Summary of Contents for RUSKA 7252

Page 1: ...Corporation All rights reserved Printed in USA Specifications are subject to change without notice All product names are trademarks of their respective companies RUSKA 7252 Dual Channel Digital Pressure Controller Calibrator Users Manual ...

Page 2: ...rvice center to obtain return authorization information then send the product to that service center with a description of the difficulty postage and insurance prepaid FOB Destination Fluke assumes no risk for damage in transit Following warranty repair the product will be returned to Buyer transportation prepaid FOB Destination If Fluke determines that failure was caused by neglect misuse contami...

Page 3: ...7252 Change Language Hold key for 5 seconds enter mode ...

Page 4: ......

Page 5: ...rt Gases 1 2 Warning 1 2 Symbols 1 2 General Information 1 3 Features 1 3 Fused Quartz Bourdon Tube Technology 1 3 Mercury Free 1 3 NIST Traceability 1 3 Universal Power Supply 1 4 Measure While Control 1 4 Friendly Display 1 4 Automatic Zero Adjust 1 4 Automatic Head Correction 1 4 Choice of Medium 1 4 Choice of Display Units 1 4 Adjustable Pressure Display 1 4 Ease of Operation 1 4 Easily Progra...

Page 6: ...Normal Mode 2 8 Fast Mode 2 8 Alignment of Inner Loop with Outer Loop 2 9 PID Control 2 9 Transducer Module 2 10 Quartz Bourdon Tube Sensor Transducer01 2 10 Sensor Board 2 11 Linearization Term 2 11 Auxiliary Sensors 2 11 Case Reference Vacuum Sensor Option 2 12 Software 2 12 Software Safety Controls 2 12 Preventing Operator Errors 2 12 Pneumatic Errors 2 12 Shut Offs 2 12 Oven Control 2 12 Press...

Page 7: ...Menu 4 9 Menu Setup 4 10 Menu Setup Mode 4 10 Menu Setup Limits 4 11 Low Limit 4 11 Auto Vent 4 11 Control Band 4 12 Control 4 12 Slew Rate 4 13 Slew Limit 4 13 Access 4 13 Menu Setup User 4 13 Menu Setup Units 4 15 Menu Setup System 4 18 Menu Calibrate 4 19 Calibration Password 4 19 Zeroing 4 19 Menu Program Storing A Sequence in Memory 4 20 Preparing to Program 4 20 Entering a New Program 4 21 A...

Page 8: ... 7252 5 20 6 Maintenance 6 1 Introduction 6 1 Observing the Software Version Number 6 1 Preventive Maintenance 6 1 Initiating the Calibrator s Self Test 6 1 Removing the Calibrator s Cover 6 2 Moisture Filter 6 2 Particle Filters 6 2 Vacuum Pumps 6 3 Processor Battery 6 3 Calibration 6 3 Calibration Instructions 6 3 Preparation 6 4 Storing the Coefficients 6 6 Vacuum Negative Gauge Calibrations 6 ...

Page 9: ...ing 6 21 7 Preparation for Storage and Shipment 7 1 Introduction 7 1 Disconnecting the Calibrator 7 1 Packing Instructions 7 1 Shipping Instructions 7 3 Appendices A Summary of Specifications A 1 B Summary of Error Messages B 1 ...

Page 10: ...RUSKA 7252 Users Manual vi ...

Page 11: ... 7252 Calibrator Options List 1 5 2 1 Conversion Factors 2 3 2 2 Solenoid Valves States 2 5 3 1 General Specifications and Parameters 3 2 6 1 Electronics Self Test 6 2 6 2 RUSKA 7252 Calibrator Parts List 6 20 6 3 RUSKA 7252 Calibrator Replacement Parts List 6 21 ...

Page 12: ...RUSKA 7252 Users Manual viii ...

Page 13: ...re Main Menu 4 5 4 7 Setting up Step Jog Main Menu 4 6 4 8 Channel A Mode Menu 4 7 4 9 Channel A Main Menu 4 7 4 10 Menu Key Selections 4 9 4 11 Channel A Menu Setup Menu 4 10 4 12 Channel A Menu Setup Limits Menu 4 11 4 13 Channel A Menu Setup User Menu 4 13 4 14 Channel A Menu Setup Units Menu 4 16 4 16 Channel A Menu Setup Remote Menu 4 17 4 17 Channel A Menu Setup System Menu 4 18 4 18 Channel...

Page 14: ...ode Menu Test Self Menu 6 1 6 2 Calibration Screen 6 4 6 3 Vacuum Negative Gauge Calibration 6 7 6 4 Zeroing Menu 6 11 6 5 Zeroing in Progress 6 12 6 6 ZeroSet Menu 6 14 6 7 Mechanical Zeroing Screen 6 14 6 8 Adjustment Bar Screen 6 15 6 9 Photocell Location 6 15 6 10 Menu Menu Test Control Menu 6 16 6 11 Auto Tune Procedure Screen 6 18 6 12 Mode Menu Test Shop1 Menu 6 19 7 1 Packing the Calibrato...

Page 15: ...libration Repair USA 1 888 99 FLUKE 1 888 993 5853 Canada 1 800 36 FLUKE 1 800 363 5853 Europe 31 402 675 200 China 86 400 810 3435 Japan 81 3 3434 0181 Singapore 65 738 5655 Anywhere in the world 1 425 446 5500 Or visit Fluke s website at www fluke com To register your product visit http register fluke com To view print or download the latest manual supplement visit http us fluke com usen support...

Page 16: ...has been damaged or destroyed because electrostatic discharges at levels less than 4 000 volts cannot be seen felt or heard Compressed Gas Use of compressed gas can create an environment of propelled foreign matter Pressure system safety precautions apply to all ranges of pressure Care must be taken during testing to ensure that all pneumatic connections are properly and tightly made prior to appl...

Page 17: ...applications are found in research laboratories wind tunnel testing power plant testing and bubbler tank volume accountancy systems It is also used to monitor barometric pressures vacuum systems and differential pressure devices The RUSKA 7252 has two full scale pressure ranges and two pressure controllers integrated into one instrument Features The following features are available on all RUSKA 72...

Page 18: ...ssure between the Calibrator and the device under test DUT taking into account the density of the test gas e g air or nitrogen Choice of Medium Although the Calibrator is not sensitive to the type of gas used within the system the user can select either instrumentation air or nitrogen allowing the Calibrator to automatically make pressure head corrections Choice of Display Units Standard units inc...

Page 19: ...programmable Communications Interface The Calibrator includes standard RS 232 serial and IEEE 488 interfaces The user s computer communicates with the Calibrator through the Standard Commands for Programmable Instruments SCPI protocol Standard Equipment Options A standard Calibrator includes this manual and a power cord Although the standard Calibrator is fully functional with just these items and...

Page 20: ...RUSKA 7252 Users Manual 1 6 ...

Page 21: ...es DIGITAL CONTROL BOARD 2 BACKPLANE BOARD POWER SUPPLY MICROPROCESSOR BOARD IEEE CARD FRONT PANEL AC POWER PNEUMATICS Reference Port Test Port Supply Pressure Port Exhaust Port Pneumatics Module 1 CASE TUBE Photo Sensor Primary Transducer Module 1 INNER LOOP SENSOR Electronic Module PNEUMATICS Reference Port Test Port Supply Pressure Port Exhaust Port Pneumatics Module 2 SENSOR SENSOR BOARD SENSO...

Page 22: ...version factors that the Calibrator uses to translate the internal pressure unit of measure of kPa into the units selected by the user These factors are given in Table 2 1 Data that is subject to change after the Calibrator leaves the factory are held in electrically erasable programmable read only memory EEPROM This includes the current units of measure the coefficients from the zeroing process t...

Page 23: ...meters of altitude per MIL STD 859A User1 user defined kPa x user defined User2 user defined kPa x user defined Pa user defined Pascals kPa x 1000 0 hPa user defined hectopascals kPa x 10 0 FS percent of full scale Digital Control Board The Digital Control Board plugs directly into the Back plane Board This board reads a high speed silicon strain gauge pressure transducer PDCR connected to the pre...

Page 24: ... The valves filters and transducers that make up the pneumatics module of a Gauge mode or Simulated Absolute Calibrator are shown in Figure 2 2 The Schematics for the Absolute mode Calibrator is shown in Figure 2 3 In the sections that follow the Zero Isolation Apply and Release valves are all 24 volt DC solenoid valves that are either open or closed depending on the Calibrator s operational mode ...

Page 25: ...atics Figures 2 2 and 2 3 summarize the Pneumatics of the Calibrator Reference Port For gauge measurements the Reference Port is normally left open to atmosphere The Reference Port is isolated from the Test Port by a solenoid valve that is closed during the Calibrator s Measure and Control modes When the user commands the Calibrator to perform the zeroing process the solenoid automatically opens a...

Page 26: ...ls to operate in this mode each sensor must have a vacuum sensor installed In gauge mode the reference port is open to atmosphere In the absolute mode a vacuum pump evacuates the reference port of the sensor Once a vacuum level of less than 200 mtorr is achieved the operator can zero the RUSKA 7252 The RUSKA 7252 would zero the RUSKA quartz sensor against an internal vacuum sensor measuring this r...

Page 27: ...or gauge instruments the Calibrator controls pressure at the maximum rate towards zero psig When the primary sensor reads that the pressure is within 1 FS pressure of zero psig the controller is turned off and the reference zeroing solenoid is opened which vents the remaining test port pressure to atmosphere If the Calibrator is at a sub atmospheric pressure then the system will control to zero ps...

Page 28: ...requency response strain gauge sensor as its reference The frequency response of this transducer allows for high speed modulation of the solenoids This sensor is aligned to the high accuracy quartz sensor when the system is Auto tuned The outer loop is a lower frequency response analog digital loop The outer loop uses a calibrated forced balanced sensor This sensor is used to monitor the pressure ...

Page 29: ... the Auto Tune feature See Chapter 6 Maintenance for details on the Auto Tune functions of the RUSKA 7252 PID Control The outer loop pressure controller is a form of PID control executed every 100 milliseconds 10 times per second The pressure is controlled to an exponential decay curve A S dt d d dt A S i A S p V S Set point A Actual V Control Output d i p Control Coefficients Figures 2 4 show a t...

Page 30: ... its zero position thus a force balance is created As pressure is applied in the helical tube the entire apparatus attempts to rotate This causes the mirror to move the reflected light spot to shine more on one photodiode than the other The Sensor Board see the next section in this Chapter Sensor Board then responds by changing the current to the electromagnetic coils that through interaction with...

Page 31: ...n mechanical characteristics of the helical tube and its supporting structure this pressure current relationship is slightly nonlinear The nonlinear portion of this pressure current relationship closely follows the form of a second order polynomial or 2 c bP aP l where again P is pressure and a b and c are coefficients generated during the calibration procedure as discussed below When the user per...

Page 32: ...ntrol valves and an error message is generated Additionally a vent limit may be set The Calibrator will go to Vent mode when the pressure exceeds this limit Shut Offs Measure mode can be entered at any time by pressing the Measure key on the main keypad with no further acknowledgment required The Calibrator will turn off the controller Oven Control The oven temperature is controlled via a pulse wi...

Page 33: ... the status of the fan it will remain in that condition until the operator changes the setting glb42 bmp Figure 2 7 Menu Menu Display Temp Screen Pressure Reading and Correction The sensor s analog output is processed by an analog to digital circuit that results in an output referred to as counts This output is corrected for the applied effects listed below The counts are linearized and the result...

Page 34: ... 381 975 full scale of current sensor KnH Zero corrected counts for upper limit of range When the zero corrected counts from the A D exceed this value the next higher range will be used if possible 7 381 975 full scale of current range KnL Zero corrected counts for lower limit of range When the zero corrected counts from the A D are below this value the next lower range will be used if possible 7 ...

Page 35: ...libration report user specified instrument options If necessary report any shipping damage to the freight agency Remove all shipping and packing materials including the shipping plugs from all components If possible save the packing materials for future shipping needs Finally install the Calibrator in a location that meets the requirements listed in Table 3 1 Note The Calibrator should be handled ...

Page 36: ...Calibrator s full scale as a pressure supply Pressure supply must be regulated and meet all criteria as stated in Appendix A of this manual Never apply more than 110 of the Calibrator s full scale to the test port Never try to control while a pressure source is connected to the test port W Caution Do not expose the instrument to thermal and mechanical shock or vibration This may affect performance...

Page 37: ... copper tubing is acceptable Exhaust Port The exhaust port may be left open to atmosphere under most conditions A vacuum pump is required in Absolute mode for controlling pressure below atmospheric pressure and will allow lower pressure control in Gauge mode i e to control to 0 psig Supply vacuum lines must have minimum restrictions Tubing should have a minimum I D of 1 4 inch In small rooms the e...

Page 38: ...is indicated in the current unit of measure to the left hand side of the measured pressure valve W Warning The software protects the lower pressure sensor from over pressurization when this mode is activated If this feature is turned on make sure that the test ports are disconnected prior to turning this feature off Reference Port The reference port is open to atmosphere for gauge measurements or ...

Page 39: ...ently absolute systems a vacuum pump capable of producing a vacuum level of 200 mTorr or less at the sensor reference port is required used to zero the sensor See Appendix A for vacuum pump requirements See also Chapter 3 Absolute Mode Requirements section For instruments that have a barometric reference sensor option the barometer is tied to the reference port When operating in the gauge mode the...

Page 40: ...RUSKA 7252 Users Manual 3 6 ...

Page 41: ...een units of measure MODE held down for 5 seconds changes the language It also switches to the single display mode and toggles between the two channels in the single channel display mode MEASURE is used to place both channels into measure mode CLEAR key will clear the numeric entry field The ENTER key accepts the entered number or confirms a command Function Keys These are the six keys that run ve...

Page 42: ...enu Run program m ed test sequences Edit Edit program instruction pressure tolerance dwell etc Nam e Change program nam e Sweep Self Sweep pressures a num ber of cycles between two points Perform self test Test Enter Test m enu Rem ote Display rem ote status Disp Display transducer values Control Tune control valve param eters Cal Enter calibrate m enu Zero Zero Sensor Delete Delete a saved progra...

Page 43: ... confirm the operation The F5 key places the unit either the stop or the jog mode and the rotary knob is then used to set the control set point by the correct step or jog amount To go to one of the menus press the F6 key Dual Control Screen The Calibrator should display a screen similar to the one shown below at power up when the instrument is set up utilizing independent test ports When the syste...

Page 44: ...he two channels Channel A is recognizable by the dark blue background color and channel B has a lighter background color Select Channel A to proceed with the tutorial glb15 bmp Figure 4 4 Selecting Channel A Main Menu This is the Channel A Main Menu The double sized numbers in the top center of the display shows the current measured pressure 0 00 psi diff The upper left corner shows the current mo...

Page 45: ...ll return to the MAIN screen with the current units The second part of this tutorial uses the Calibrator to generate pressure The pressure supply must be connected and the test port must be connected to a closed volume in accordance with Chapter 3 Pneumatic Connections of this manual 4 From the Main Menu use the numeric keypad to enter the starting pressure The pressure is entered in the units set...

Page 46: ... use the step function Using the rotary knob rotate the knob clock wise to increase the set point or counter clock wise to decrease the controller set point The scratchpad will be updated with a new set point The step size defaults to 10 of full scale This step size is user defined and can be changed in the Menu Setup User menu glb19 bmp Figure 4 7 Setting up Step Jog Main Menu 9 Press ENTER to ac...

Page 47: ... Menu displays the measured pressure in double sized numbers Below the pressure reading is the current unit of measure and mode Gauge or Absolute The Main Menu can always be reached by repeatedly pressing Previous The RUSKA 7252 is designed such that all of the commonly used functions are accessible by a direct key on the key pad or from a top level function key Less commonly used set up type func...

Page 48: ...umeric scratchpad Note The set point can also be changed using either the Step or the Jog function See Chapter 6 Step Jog Entering Exiting Control Mode 1 The Control mode is set from the Main Menu Press PREVIOUS until the Main Menu appears 2 Press Control F2 to enter Control mode ENTER must be pressed to confirm entry into Control mode Note Any entry in the numeric scratchpad will also be taken as...

Page 49: ...d in the Step Jog the F5 key Using the rotary knob rotate the knob clock wise to increase the set point or counter clock wise to decrease the controller set point The scratchpad will be updated to a new set point The step size defaults to 10 of full scale Press ENTER to accept the new set point Setting Step Size From the Main Menu press Menu F6 Setup F2 User F2 Using the rotary knob move the curso...

Page 50: ...t When the absolute mode key is selected the instrument instantly adds the barometric pressure reading to the primary sensor allowing the instrument to operate in the absolute mode The second optional configuration allowing a unit to operate in the absolute mode is the Evacuated Reference Option With this option the reference pressure of the primary differential quartz sensor is evacuated This opt...

Page 51: ...unit will not accept the value and it will generate an error code informing the user that they have entered a set point that is greater than the high pressure limit In control mode if for any reason the pressure exceeds the user defined limit it will change into the measure mode and again display an error message to the operator informing them of the error that occurred This value can be edited us...

Page 52: ...es in the Active control mode Setting a Control On and Off Band places the Calibrator in the Passive control mode The Control On and Off Band provides a tolerance around the pressure set point in the current unit of measurement The Controller will control the pressure to the commanded set point Once the actual pressure is within the user defined Control Off Band tolerance the controller will shut ...

Page 53: ...ceeded If the slew rate is exceeded the Calibrator will change from the control mode to the measure mode and it will generate an error message to the operator Access The test access password allows the user to protect access to Calibrator configuration and programs If the test access password is set to any number other than zero factory default it is required before the user is allowed to change t...

Page 54: ...ce under test and the Calibrator s pressure reference plane Once the user inputs the head height and selects air or nitrogen the Calibrator automatically corrects for head pressure 1 The Pressure Reference Line on the Calibrator is defined as the bottom of the color display where the display and the front panel join This provides the reference plane against which the device under test DUT pressure...

Page 55: ...IOUS until the Main Menu appears press Menu F6 Setup F2 User F2 2 Turn the rotary knob until the label Display digits is highlighted 3 Turn the rotary knob further until the desired number of digits from the default resolution is highlighted 1 0 1 and then press the ENTER key to select Key Click The Calibrator can be configured to emit a clicking sound each time a key is pressed 1 The key click is...

Page 56: ...re defined from the Units Define Menu From the Main Menu press PREVIOUS until the Main Menu appears press Menu F6 Setup F2 Units F3 2 Use the rotary knob to highlight the desired user defined unit and then select the Edit Name F1 function key glb27 bmp Figure 4 15 Channel A Menu Setup Units Edit Name Menu ...

Page 57: ...conversion factor and press ENTER to accept 6 Press PREVIOUS three times to return to the Main Menu The new unit definition may now be selected using the units key Menu Setup Remote The Menu Setup Remote screen is where the remote communication interface is set up glb28 bmp Figure 4 16 Channel A Menu Setup Remote Menu GPIB Address Sets the IEEE 488 interface address Protocol The Protocol defines w...

Page 58: ...u press PREVIOUS until the Main Menu appears press Menu F6 Setup F2 System F5 2 To set the system date turn the rotary knob until Date is highlighted Use the numeric keypad to enter the current four digit year month and day yyyymmdd All digits must be entered Press ENTER to accept 3 To set the system time turn the rotary knob until Time is highlighted Use the numeric keypad to enter the current ho...

Page 59: ...either channel Calibration Password The calibration password allows the user to protect access to Calibrator calibration constants and the calibration procedure If the calibration password is set to any number other than zero it is required before the user is allowed to calibrate the Calibrator or manually change the calibration constants Note It is recommended that the access password be recorded...

Page 60: ... stored in the Calibrator s memory as a program One benefit of storing a sequence in memory is that the user does not have to command each pressure separately every time a multipoint test or calibration routine is performed Another benefit is that the user can specify a tolerance for each set point pressure Once a tolerance is set the dwell timer will start counting down instead of waiting until t...

Page 61: ...lapses the Calibrator will automatically proceed to the next set point in the program even if the current set point has not been achieved Thus the max time selection limits the amount of time that the Calibrator can spend on any one set point Typically the max time should be set to a value greater than the dwell time If the max time is set to zero the Calibrator will attempt to achieve the set poi...

Page 62: ...light new 4 Press Edit F4 Since new was highlighted the Calibrator will create a new program and give a default name of NAMEnn where nn is a two digit number The program editing screen will appear displaying the first step glb31 bmp Figure 4 19 Channel A Menu Program Edit Menu 5 Using the numeric keypad enter the values for Pressure Tolerance Dwell time and Max time pressing ENTER after each value...

Page 63: ...een See Chapter 4 Changing the Name of a Program Automatically Generating a Program For the Calibrator to automatically generate a program the user must input the first set point pressure the last set point pressure and the number of steps in between as well as the dwell time max time and tolerance common to all set points 1 Ensure that the units limits and control parameters are set to their desi...

Page 64: ... Main Menu press Previous until the Main Menu appears press Menu F6 Program F4 In addition to changing the name of an existing program a new program may be initiated by selecting new and performing the same steps as outlined to change the name of a program 2 Use the rotary knob to highlight the current name For a new program name select new 3 Press Edit F4 The program editing screen will appear di...

Page 65: ...nel A Menu Program Edit Menu 4 The rotary knob can be used to move through the program and highlight the value you wish to edit Use the keyboard to enter a new value This value will show up in the scratch pad located at the bottom of the window Press Enter to accept the edited value 5 To add a step to the program first move to the step after the new step For example to insert a step between steps ...

Page 66: ... Calibrator will be set to the configuration stored with the program glb35 bmp Figure 4 23 Channel A Menu Program Config Menu 5 Press PREVIOUS until the Main Menu appears 6 Press Setup F2 Limits F1 Change the desired parameters using the normal procedures 7 Return to the Main Menu by pressing PREVIOUS three times 8 Press Menu F6 Program F4 9 Use the rotary knob to highlight the name of the program...

Page 67: ...librator stored with the program is restored the pressure set point is set to the pressure value in the first step and the Calibrator is placed in Control mode Run will now be highlighted and the program will proceed through its steps 5 To pause the program press Pause F3 Pause will now be highlighted and the Calibrator will continue controlling to the current set point The Calibrator will maintai...

Page 68: ...ically exercise the elastic sensing element of the device under test prior to performing a calibration For the Calibrator to perform the sweep test input the high and low set point pressures the pressure control tolerance the dwell time at set point and the number of cycles to perform 1 Ensure that the units limits and control parameters are set to their desired values 2 The sweep test is entered ...

Page 69: ...Test Self Test The Calibrator can perform electrical and pneumatic self test to assist in troubleshooting potential problems Refer to Chapter 6 Maintenance for more details Note In order to perform a pneumatic self test the supply port must be connected to a properly set supply pressure and the test port not open to atmosphere For absolute units a vacuum supply must also be connected to the exhaus...

Page 70: ...on from the serial ports glb39 bmp Figure 4 27 Channel A Menu Test Remote GPIB Menu Menu Test Shop1 The Menu Test Shop1 menu of the system is used to display the current status of the various valve positions in the system This menu is primarily used for diagnostics and will be discussed further in Chapter 6 Maintenance glb40 bmp Figure 4 28 Channel A Menu Test Shop1 Menu ...

Page 71: ...ntrol valves are replaced or to perform maintenance on the controller This menu is primarily used for diagnostics and repair and will be discussed further in the Chapter 6 Maintenance glb41 bmp Figure 4 29 Channel A Menu Test Controller Menu Menu Display The Menu Display is used to conveniently monitor most of the sensor output parameters It is primarily used for troubleshooting This display scree...

Page 72: ...RUSKA 7252 Users Manual 4 32 ...

Page 73: ...ommands for Programmable Instruments IEEE 488 The following identification codes define the interface capabilities of the Calibrator Identification codes are described in the IEEE 488 standard SH1 Source Handshake Complete Capability AH1 Acceptor Handshake Complete Capability T5 Talker L3 Listener SR1 Service Request Complete Capability RL1 Remote Local Complete Capability PP0 Parallel Poll No Cap...

Page 74: ...nnected to an interface Most functions that can be performed in Local mode can also be performed remotely Remote mode does not automatically disable local operation The remote interface may be active while local operations are being done In cases where full remote control is required the following methods may be used 1 Issue a Local Lockout LLO interface message via the IEEE 488 interface The Cali...

Page 75: ...suffix If omitted the suffix defaults to 1 Multiple commands may be placed in a single message separated by semicolons Each command starts at the same level of tree where the last command stopped unless the command starts with a colon The first command in a message and any commands starting with a colon start at the root of the command tree IEEE 488 2 commands may occur between SCPI commands witho...

Page 76: ...two channels selecting the lowest pressure range channel within the range of the commanded set point to control thereby optimizing the performance In the standard configuration the test ports are isolated from one another and the communication is performed independent of each channel For instance a command MEAS PRES would be sent to read the channel A pressure To read the channel B pressure the co...

Page 77: ...er number high pressure limit VENT number auto vent limit CALibration MODE calibration edit enabled MODE number request calibration edit PRESsure A Pressure VALue n number Perform calibration point DATA POINts return number of calibration constants VALue n returns label value C0 0 123 VALue n number sets calibration constant CALibration VALue n return nominal calibration point POINts return number...

Page 78: ...TEMPerature A Gas Temperature Same as PRESsure2 above TEMPerature2 A Sensor Temperature Same as PRESsure2 above TEMPerature11 B Gas Temperature Same as PRESsure2 above TEMPerature12 B Sensor Temperature Same as PRESsure2 above DISP ENABle ON OFF 1 0 turns front panel display on off TEXT text display message on front panel PRESsure BGRaph number sets A bar graph maximum PRESsure11 BGRaph number set...

Page 79: ...esolution MODE ABSolute DIFFerential GAUGE TARE RANGE UPPer full scale value in units calibrated LOWer returns low cal point REFerence HEIGht number gas head height MEDium N2 AIR gas head medium SOURCE PRESsure A LEVel IMMediate AMPLitude number pressure control setpoint MODE FIXed LIST set control mode TOLerance number specifies output tolerance SLEW number set slew rate CONTrol number control ba...

Page 80: ...ength Freq ignored DATE year month day system date ERRor returns error descr info or 0 No Error KLOCk ON OFF 1 0 keyboard lock TIME hour minute sec system time VERSion SCPI protocol version returns 1991 0 LANGuage COMP 6000 SCPI set interface emulation PRESet reset pressure control COMMunicate SERial RECeive TRANsmit BAUD number PARITY EVEN ODD NONE BITS 7 8 SBITs 1 2 GPIB ADDRess number TEST ELEC...

Page 81: ...nt and Enable Condition registers always show the current status of the instrument Bits may turn on and back off between reads The status read is the status of instrument at the moment of the read Condition registers include STB Status Byte Register ESR Standard Event Status Register STAT OPER COND Operation Status Condition Register STAT QUES COND Questionable status Condition Register Event regi...

Page 82: ...ved 0 Standard Event Status Register ESR Standard Event Status Enable Register ESE Bit 7 Power on Set at power up Bit 6 Reserved 0 Bit 5 Command error Error in command syntax Bit 4 Execution error Error in command execution Bit 3 Device dependent error Device error independent of commands Bit 2 Query error Output queue empty when request received Bit 1 Reserved 0 Bit 0 Operation complete Set for O...

Page 83: ...turn hexadecimal 0D or a line feed hexadecimal 0A The responses are always terminated by a carriage return followed by a line feed The serial port also supports XON XOFF When the XOFF hexadecimal 13 command is received the Calibrator will stop transmitting Transmission is restarted when the XON hexadecimal 11 command is received When only one unit is attached the Control C hexadecimal 03 command w...

Page 84: ...RES TOL 0 001 Set control tolerance to 0 001 FS OUTP MODE CONTROL Enter control mode write_7000 UNIT FS PRES 20 0 TOL 0 001 OUTP MODE CONTROL n if check_errors ibonl device 0 return Read pressure status until setpoint is reached MEAS Read pressure STAT OPER COND Read status setpoint while kbhit request_7000 MEAS STAT OPER COND n pressure strtod buffer p status atoi p if check_errors continue if st...

Page 85: ...mmand to the 7250 void write_7000 char s ibwrt device s strlen s request_7000 write a query command and read the response void request_7000 char s ibwrt device s strlen s ibrd device buffer sizeof buffer Sample Program 2 RUSKA 7252 GPIB IEEE 488 Zero Sequence Sample Program 2 RUSKA 7252 GPIB IEEE 488 Zero Sequence include stdio h include stdlib h include string h include conio h include decl h int...

Page 86: ...e 0 Zero perform zero adjust of RUSKA 7252 int zero void int cstat pstat tstat rstat clrscr cprintf Zeroing gotoxy 1 5 cprintf Pressure Reading gotoxy 1 6 cprintf Sensor Temperature gotoxy 1 7 cprintf Reference Pressure Enter Zero Mode CAL ZERO INIT write_7000 CAL ZERO INIT n Wait for calibration values to be within limits CAL ZERO INIT do if kbhit getch break request_7000 CAL ZERO INIT n sscanf b...

Page 87: ... do request_7000 STAT OPER COND n sscanf buffer d status if check_errors return 0 gotoxy 1 9 cprintf Zeroing while status 1 0 gotoxy 1 9 cprintf Zero Complete return 1 check_errors display all GPIB and RUSKA 7252 error messages return TRUE if any errors were found int check_errors void unsigned char status7 int retval Check for GPIB Interface Errors if ibsta ERR cprintf GPIB Status 4X Error d r n ...

Page 88: ...lude time h define TRUE 1 define FALSE 0 define TIMEOUT CLK_TCK 5 5 second timeout define XON 0x11 define XOFF 0x13 define CLEAR 0x03 define DLE 0x10 define QUEUE_SIZE 1024 char buffer QUEUE_SIZE buffer for input output strings double pressure Pressure read from unit int status Status register from unit int address int portbase int intnum volatile int transmit_enabled TRUE char inqueue QUEUE_SIZE ...

Page 89: ...us setpoint while kbhit if request_7000_serial MEAS STAT OPER COND n printf Timeout n continue pressure strtod buffer p status atoi p if check_errors continue if status 0x10 printf Pressure 9 3lf n pressure if status 2 0 break Reset RUSKA 7252 to Measure mode OUTP MODE MEASURE Enter Measure mode write_7000_serial OUTP MODE MEASURE n check_errors Reset Serial Interface serial_close check_errors dis...

Page 90: ...msg 10 int divisor unsigned v portbase 0x3F8 COM1 0x3F8 COM2 0x2F8 intnum 4 COM1 4 COM2 3 outportb portbase 3 0x80 outportb portbase 1 0 outportb portbase 0x0C 9600 Baud outportb portbase 3 3 8 Databits No Parity 1 Stopbit old_vector getvect intnum 8 Save old interrupt vector setvect intnum 8 serial_int Set new interrupt vector v inportb 0x21 Enable interrupt v 1 intnum outportb 0x21 v outportb po...

Page 91: ... Address while s Write string serial_write s request_7000_serial write a commmand and read the response int request_7000_serial char s int i char ch clock_t start current write_7000_serial s Write Command i 0 while i QUEUE_SIZE 1 start clock while inq_in inq_out Wait for a character current clock if current start current CLK_TCK 86400 if current start TIMEOUT Check for timeout buffer i 0 return FA...

Page 92: ...SIC Example for RUSKA 7252 REM INCLUDE C GPIB PC QBDECL BAS DIM READING AS STRING 30 CALL IBDEV 0 4 0 12 1 H40A R7010 CALL IBCLR R7010 CALL IBWRT R7010 MEAS chr H0A CALL IBRD R7010 READING PRINT READING CALL IBONL R7010 0 END Note EOM EOS are linefeed ...

Page 93: ...software version number will appear on the screen 3 Press PREVIOUS to return to the previous screen Preventive Maintenance Although the Calibrator is designed to be nearly maintenance free occasional preventive maintenance is required to keep the Calibrator s performance optimal Initiating the Calibrator s Self Test To test the Calibrator s hardware and software follow the steps below 1 If necessa...

Page 94: ...ould only be opened by qualified electrical mechanical service technicians Lethal voltages are present and exposed in the power supply and display 1 Turn off the Calibrator and disconnect the power cord from the Calibrator 2 Locate and unscrew the four screws that secure the cover to the back panel 3 Place your hands near the middle of the cover and slide the cover towards the Calibrator s back pa...

Page 95: ...in a new battery part number 4 725 5 Reinstall the processor card the bracket that locks the display cable in place and the screw Replace the instrument cover 6 The time and date may have to be re entered See Chapter 4 Menu Setup Remote Calibration To keep the Calibrator operating within its specified precision the calibration procedure described below should be performed once every year If a high...

Page 96: ...n screen select MENU MENU CALIBRATION glb44 bmp Figure 6 2 Calibration Screen 8 When you first enter the Calibration menu the top left hand side of the display will indicate which sensor is being the viewed The sensors coefficients are then shown below the sensor label On the RUSKA 7252 there are two primary sensors The first sensor that is shown is the primary measuring sensor A This is indicated...

Page 97: ...dard This is used as a troubleshooting tool If one point has a significantly higher adjustment required than other points in the calibration this may indicate that there was an error in that specific calibration point The operator can re check this pressure point prior to completing and accepting the full calibration 2 The Step 1 actual value will be highlight This is your first pressure point in ...

Page 98: ...if one point has a significantly higher adjustment required than other points in the calibration This may indicate that there was an error in that specific calibration point The operator can re check this pressure point prior to completing and accepting the full calibration To re enter a point use the rotary knob and move the highlighted curser to the actual pressure values in the step in question...

Page 99: ...connected to the bell jar with a cutoff valve to isolate it from the DUT 4 Additionally there must be a cutoff valve located between the Vacuum pump and the bell jar 5 Close the Cut off valve to isolate the DUT test port from the bell jar 6 Open the Vacuum Pump Valve to pull a hard vacuum on the bell jar to seal the bell jar and to float the masses 7 Once the masses have risen in response to evacu...

Page 100: ...st calibration screen will appear 7 You will use the calibration standard to apply the various pressures that will be requested by the RUSKA 7252 The screen will display a table noting the following information a Step The pressure step in the calibration sequence b Apply The pressure that the standard is to generate to the Calibrator c Actual The actual pressure value that was generated by the sta...

Page 101: ...ibration process press CALIBRATE If the calibration access code is enabled enter it at the prompt The first calibration screen will appear You will use the calibration standard to apply the two vacuum points on the vacuum sensor The Actual value will be highlighted This is your first pressure point in the calibration procedure This calibration requires the generation of two pressures within the ra...

Page 102: ...ptional Barometric Reference sensor this is labeled Atmospheric Sensor 4 To edit the calibration coefficients press the CALIBRATE button If the calibration access code is enabled enter it at the prompt The first calibration screen will appear Note To exit the calibration procedure before the calibration coefficients have been changed press Cancel any time during the procedure Canceling restores al...

Page 103: ...f the pressure sensor Stability and Temperature If any of the above are unstable then the system will delay until stability is achieved Pressing OK F6 will bypass this wait period Note Bypassing this wait period can have a negative effect on the zeroing procedure Gauge and Vacuum Negative Gauge Instruments 1 Verify that the Reference Port is open to atmosphere 2 Enter the Calibration screen by sel...

Page 104: ...t of measure for the Vacuum sensor press the Unit key and then the Vacuum F2 key 2 Enter the Calibration screen by selecting MODE MENU CALIBRATE 3 Select Zero F1 Do not press the Calibrate button When initiating the zeroing command in the Calibrator it will cycle the internal valves allowing the external vacuum pump to pull a hard vacuum on the RUSKA sensor It is recommended that the sensor be pul...

Page 105: ... pressure Press ENTER Sensor Photocell Zeroing If the error message Mechanical Zeroing Needed is displayed the sensor photocell must be zeroed The following steps describe this process Press the MODE key to select the desired channel WX Warning The Calibrator should only be opened by qualified electrical mechanical service technicians Lethal voltages are present and exposed in the power supply and...

Page 106: ...cells by placing the tool in the hole in the back of the sensor and turning the tool slightly The screen will show a number of horizontal lines The top yellow bar represents the current zero setting The bottom portion of the bar has a green bar in the center and two red bars on either end If the top yellow bar is over the red bar then mechanical zeroing is required If the yellow bar is over the gr...

Page 107: ...ening the Allen screw and now offset it in the opposite direction by this same width 10 Again tighten the Allen screw Now the width of the yellow line should be minimized 11 Tap on the bracket with a screwdriver handle to relieve mechanical stress Continue to tap on the bracket until the counts stop changing 12 If the zero moved significantly as a result from tapping the bracket repeat this proced...

Page 108: ...ol optimally it is recommended to first assure that the system is free of leaks and is operating within the external volume specifications see Appendix A 1 You should verify that the instrument is fitted with the proper sized pressure lines to minimize flow restrictions see Chapter 3 Pneumatic Connections 2 Verify that the control band is set as intended see Chapter 4 Control Band For active contr...

Page 109: ...ond the recommended settings Note Prior to performing any Auto Tune functions in an effort to improve the controller performance confirm that the system is a leak free system and the volume attached to the test port is within the recommended range see Appendix A Additionally assure that the system has adequate pressure and vacuum supply when required To perform these Auto Tune functions the instru...

Page 110: ... of the oven temperature control The temperature of the sensor should be controlled to 50 ºC The Duty cycle indicates the percentage of time that the oven control is turned on in order to maintain the oven at the proper set point of 50 ºC A unit that is operating properly after it has fully warmed up should indicate a sensor temperature of 50 ºC and a duty cycle between 10 to 90 If operating the i...

Page 111: ...ons port and the image file 5 When the upgrade is finished Update7 running on the PC and the 7XXX should both display Complete RUSKA 7252 Controller Software Upgrade In addition to the main code the RUSKA 7252 includes code for the pressure controller The controller software version can be viewed by pressing the MENU TEST REMOTE SERIAL2 keys The controller software version is displayed next to Ctr...

Page 112: ...plete Finally the main software only reads the software versions on power up So following the controller code upgrade pressing the MENU TEST REMOTE SERIAL2 keys will only show the new revision level of the controller code after power is cycled on the RUSKA 7252 Replacement Parts The following is a list of the common replacement parts used in the RUSKA 7252 Calibrator Table 6 2 RUSKA 7252 Calibrato...

Page 113: ...9 Battery 3911212 IEEE Board 3879645 CPU Board 3876760 Sensor LED Lamp Assembly 3908093 Sensor Photocell 3878975 Photocell Adjustment Tool 3879554 Power Supply 3962098 Fan Assembly 3878927 Rotary Encoder 3878543 Front Panel Keyboard Electronic Card Cleaning When necessary clean externally using a damp lint free cloth and mild liquid detergent ...

Page 114: ...RUSKA 7252 Users Manual 6 22 ...

Page 115: ...s To prevent shipping and handling damage to the instrument adhere to and strictly follow the instructions below The governing discipline in ensuring a damage free shipment is to ensure that the possibility of handling shocks to the Calibrator is minimized and or prevented during transit Fluke accomplishes this task by cradling the Calibrator within two foam cradles that are encapsulated within a ...

Page 116: ...acting Fluke the part number the serial number the purchase order number the billing and ship to address and the buyer s name and telephone number This information plus the RMA number must be attached to the unit when it is shipped to Fluke Calibration There will be a minimal charge for inspection and or evaluation of returned goods 2 Enclose the Calibrator in plastic or any good water barrier mat...

Page 117: ...rkings are preprinted on the carton glb53 bmp Figure 7 1 Packing the Calibrator Shipping Instructions Fluke recommends using air freight for transportation Surface transportation subjects the shipment to more frequent handling and much more intense shock In most cases if surface transportation is the mode of transport employed handling damage is likely Again it is essential that the procedures men...

Page 118: ...RUSKA 7252 Users Manual 7 4 ...

Page 119: ...e transfer standard There often is considerable confusion with the performance specification because different manufacturers use different terms to describe the performance characteristics of their instruments The two most common terms used are Accuracy and Precision In both cases as a minimum the manufacturers define these terms to be the combined effects of linearity hysteresis and repeatability...

Page 120: ...nded uncertainty of the calibration standard and include all sources of uncertainty that would influence the calibration standard including the uncertainty from the National Standards Laboratory that the standard is traceable It should also be noted that when the instrument is re calibrated the uncertainty of the device is influenced by the uncertainty of the calibration standard that will be used...

Page 121: ...ncertainty at different confidence level and therefore you would need to be able to convert from one to the other in order to compare the two devices For instance if a manufacturer states that they have an uncertainty of 0 005 FS and that the uncertainty is expressed at the 1 sigma level then it would be doubled to express it at the 2 sigma level i e it would be an 0 01 FS device at a 2 sigma or 9...

Page 122: ...nty RSS 0 009 of Reading per year The following two tables are uncertainty analysis examples for a single range RUSKA 7252 based on a three month and a yearly calibration Table A 3 Uncertainty Analysis for RUSKA 7252 Three Month Analysis Uncertainty Analysis 3 Month Calibration Interval RUSKA 7252 Uncertainty 2 sigma A Performance Linearity Hysteresis Repeatability and Temperature 0 003 of Full Sc...

Page 123: ...sensor Evacuated Reference Option The two sigma expanded uncertainty of the vacuum sensor used to monitor the reference pressure is estimated to be less than or equal to 10 mtorr 1 33 Pa per year This uncertainty component should be combined RSS with the primary sensor uncertainty when operating in the absolute mode with an evacuated reference vacuum sensor Specifications General Specifications Pr...

Page 124: ...03 FS 0 003 FS 0 01 FS Stability Over 3 Months Over 1 Year 0 0019 RDG 3 months 0 0075 RDG year 0 01 FS Zero Drift 3 0 004 FS 24hrs 0 004 FS 24hrs 0 004 FS 24hrs 0 004 FS 24hrs Control Stability 0 001 FS 0 001 FS 0 001 FS 0 001 FS Control Low Limits 3 0 psig 0 15 psia 0 psig 0 15 psia 0 15 psia 0 psig 0 15 psia Slew Rate 4 20 Seconds 20 Seconds 20 Seconds 60 Seconds Test Port Isolation Standard non...

Page 125: ...e used to obtain 0 psig 3 Zero drift typically improves with sensor age 4 Defined as 10 FS increments into a 15 cubic inch volume Table A 7 Performance Specifications for RUSKA 7250LP Pressure Range 10 30 20 60 35 100 inH2O 25 75 50 150 85 250 mbar Mode Gauge Precision 1 From 10 to 100 Max FS 0 005 of Reading Below 10 Max FS 0 005 of 10 Max FS Stability Over 3 Months Over 1 Year 0 0019 RDG 3 month...

Page 126: ...ze Contamination 50 microns Pressure Source Max Moisture Content 50 C dew point Pressure Source Max Hydrocarbon Content 30 ppm Vacuum Requirements Supply Vacuum 50 liters per minute minimum with auto vent feature absolute units only Bypass Supply Vacuum Valve for High Pressure Gauge work Industrial grade nitrogen 99 5 pure ...

Page 127: ...nge 221 Settings Conflict The command could not be executed due to the current state of the Calibrator Some commands cannot be executed while a program self test or calibration is in progress 222 Out of Range The value is not within the valid range For pressures check high and low limits 281 Cannot create program Program memory is full 282 Illegal Program Name The name specified is not valid or do...

Page 128: ...r malfunction requesting service if necessary 533 Case Pressure Overrange Select OK then reduce the pressure at the case reference port to 30 psia or lower 540 Mechanical Zeroing Needed The zero point of the quartz Bourdon sensor is beyond the range of the compensation circuit The zero is adjusted by the software but should be manually adjusted for complete accuracy 542 Oven Control Failure The te...

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