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Keithley 7706, Руководство пользователя

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2

 

Model 7706 module

 

Connection

 

The Model 7706 is a 20-channel differential multiplexer card with the following features:

• 20 channels of analog input with 300V, 1A capacity; 60W, 125VA maximum

• 16 channels of digital output for output control

• One event counter/Totalizer

• Two analog outputs (±12V @ 5mA with 16-bit programmability) 

• 2-wire or 4-wire 

 

Ω

 

 measurement (automatically pairs switches for four wire measurements — 

 

n

 

 + 10)

• Temperature applications (RTD, thermistor, thermocouple)

• Built-in automatic cold junction reference (CJC)

• Screw terminal connections

• Designed specifically for use with Keithley’s Model 2700 Multimeter/Data Acquisition System

 

Card configuration—schematic

 

Figure 1

 shows a simplified schematic diagram of the Model 7706 module. As shown, the Model 7706 has channels that are 

grouped into two banks of ten channels (twenty channels total). Backplane isolation is provided for each bank. Each bank also 
includes separate cold junction reference points. The first bank contains channels 1 through 10 while the second bank contains 
channels 11 through 20. Each channel of the 20-channel multiplexer card is wired with separate inputs for HI/LO providing 
fully isolated inputs.

 

NOTE

 

Although the Model 7706 relays are the latching type (relays hold their state even after power has been
removed), all relay states are set to open a few seconds after either a power cycle or an *RST command is
issued.

Connections to DMM functions are provided through the card backplane connector for the following:

INPUT connections
SENSE (

 

Ω

 

4-Wire) connections

Channels 21–22 (digital output), 23–24 (analog output), and 25 (Totalizer) are controlled either over the bus or from the front 
panel. The grounds for these channels are non-isolated. Detailed information on each channel is contained later in this section.

Channel 26 (2W/4W Configuration), Channel 27 (Sense Isolation), and Channel 28 (Input Isolation) are normally automatically 
configured by the 2700. However, by using the 

 

:ROUT:MULT:

 

 commands (refer to Section 2 of the 2700 User’s Manual), they 

can be manually configured.

Содержание 7706

Страница 1: ...d User s Guide PA 719 Rev C 2 00 A G R E A T E R M E A S U R E O F C O N F I D E N C E The Model 7706 can be used with Keithley Models 2700 2701 and 2750 All references to the Model 2700 also apply to...

Страница 2: ...SEQUENTIAL DAMAGES ARISING OUT OF THE USE OF ITS INSTRUMENTS AND SOFTWARE EVEN IF KEITHLEY INSTRUMENTS INC HAS BEEN ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH DAMAGES SUCH EXCLUDED DAMAGES SHALL IN...

Страница 3: ...s that a shock hazard exists when voltage levels greater than 30V RMS 42 4V peak or 60VDC are present A good safety practice is to expect that hazardous voltage is present in any unknown circuit befor...

Страница 4: ...components in mains circuits including the power transformer test leads and input jacks must be purchased from Keithley Instru ments Standard fuses with applicable national safety approvals may be use...

Страница 5: ...outputs channels 21 22 9 Analog outputs channels 23 24 15 Totalizer 18 Totalizer channel monitor scan example 22 Specifications 24 Connection log 24 Front panel operation Card specific menu 26 Bus co...

Страница 6: ...e cold junction reference points The first bank contains channels 1 through 10 while the second bank contains channels 11 through 20 Each channel of the 20 channel multiplexer card is wired with separ...

Страница 7: ...annel 20 HI LO Channels 12 19 HI LO Sense HI LO Input Channel 26 2 Pole Open 4 Pole Closed see Note To Model 2700 Backplane Channel 28 see Note Backplane isolation Channel 27 see Note Backplane isolat...

Страница 8: ...rocedure unless qualified to do so Figure 2 shows how to access the screw terminals on the Model 7706 Channel designations for the screw terminals are con tained in Figure 3 Figure 2 Screw terminal ac...

Страница 9: ...sulation around the harness for voltages above 42V peak see Figure 4 TE2 TE3 TE1 J3 TE4 TE5 TE6 TE7 J2 H L H L H L H L H L CH11 CH12 CH13 CH14 CH15 H L H L H L H L H L CH16 CH17 CH18 CH19 CH20 CH1 CH2...

Страница 10: ...log Table 1 and affix it to the module cover 6 Close and lock cover WARNING The Model 7706 module provides connections for both high voltage analog measurements as well as dig ital earth based circuit...

Страница 11: ...le connections see Figure 5 2 Wire and thermistor connections see Figure 6 4 Wire and RTD connections see Figure 7 Voltage AC or DC see Figure 8 Figure 5 Thermocouple connections Figure 6 2 Wire and t...

Страница 12: ...e and RTD connections Figure 8 Voltage connections DC or AC Channel 1 HI LO Channel 10 HI LO Channels 2 9 Channel 11 HI LO Channel 20 HI LO Channels 12 19 RTD 4 Wire Channel 1 HI LO Channel 20 HI LO C...

Страница 13: ...mal equivalent of the binary pattern first determine the pattern mapped to the screw terminals on the desired digital output refer to the example contained in Figure 10 Setting a bit to a logic 1 effe...

Страница 14: ...38 this is the NRf value in the command 2 3 7 8 9 10 4 GND 1 Digital output CH21 GND Screw terminal number 27 26 25 24 23 22 21 20 1 0 0 0 1 0 1 0 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 1 0 0 0 1 0...

Страница 15: ...his is the NRf value in the command 2 3 7 8 9 10 4 GND 1 Digital output CH22 GND Screw terminal number 27 26 25 24 23 22 21 20 1 0 0 0 1 0 0 1 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 1 0 0 0 1 0 0 1...

Страница 16: ...mine the pattern mapped to the screw terminals on the desired digital output refer to the example contained in Figure 12 Setting a bit to a logic 1 effectively sets the screw terminal to 5V while sett...

Страница 17: ...215 214 213 212 211 210 29 28 32768 16384 8192 4096 2048 1024 512 256 1 2 4 5 6 7 3 GND 0 Digital output CH21 GND Screw terminal label 27 26 25 24 23 22 21 20 128 64 32 16 8 4 2 1 1 1 0 0 0 0 0 0 1 1...

Страница 18: ...no external power supply Output 5V 42V Maximum Model 7706 Module Digital Output Terminal Digital ground non isolated referenced to chassis User supplied circuitry Output 5V Digital Output Terminal Dig...

Страница 19: ...the analog outputs Figure 15 Analog output In the following examples the Model 7706 module is in slot one of the Model 2700 Sample 1 Set analog output 1 channel 23 to 10 0V To set analog output 1 usi...

Страница 20: ...output 2 over the bus send the following command OUTP VOLT 5 5 124 Note that each output is referenced to the chassis Each output can not float from each other To operate with the analog output in spe...

Страница 21: ...it can be calculated as follows This relationship can be modified to directly compute for percent error Using the above equation to keep loading error within 0 1 the resistance of the Model 7706 syst...

Страница 22: ...us Figure 18 shows a simplified schematic of the Totalizer connected to a function generator NOTE The Totalizer can count exactly up to 4 294 967 295 events 232 1 The count resets sets its value to 0...

Страница 23: ...ble 5 the Totalizer can be configured to read READ or read and reset RRES It can also be configured to which edge of the signal is read rising or falling The type of threshold detected by the Totalize...

Страница 24: ...front panel This opens all relays switches the Model 2700 function to Totalizer TOTALIZE and remembers the previous function In this mode the TOTalize TYPE setting is ignored effectively READ The fron...

Страница 25: ...to zero STEP SCAN DIGITS RATE ENTER Blocked Shifted SAVE SETUP CONFIG TEST GPIB RS 232 Normal operation HALT LSYNC Blocked 3 Range keys and Normal operation AUTO Blocked 4 INPUTs switch Normal operat...

Страница 26: ...ied model of scan operation is contained in Figure 22 The procedure for front panel operation and equivalent program ming commands for this simplified model is contained in Table 1 For this example th...

Страница 27: ...22 Monitor scan example 4 Measurements Measure TOTALIZER Close Monitor Channel 125 No Yes Measure Open Last Chan Close Next Chan Close First Channel Return to Monitor Mode No Yes Scan 100 000 Counts S...

Страница 28: ...ter count to 20 SHIFT TYPE 020 RDGS Enable filter FILTER FUNC VOLT 101 103 VOLT RANG 10 101 103 VOLT AVER COUN 20 101 103 VOLT AVER STAT ON 101 103 b Channel 104 Disable off Channels 104 120 SHIFT CH...

Страница 29: ...SENSE H L CH1 H L CH2 H L CH3 H L CH4 H L CH5 H L CH6 H L CH7 H L CH8 H L CH9 H L CH10 H L CH11 H L CH12 H L CH13 H L CH14 H L CH15 H L CH16 H L CH17 H L CH18 H L CH19 H L CH20 H L CH21 B0 B1 B2 B3 B4...

Страница 30: ...DIGOUT1 255 5 DIGOUT2 255 6 TOT TYPE READ RRES 7 TOT EDGE RISE FALL 8 SWREV A01 Readings mode 9 SLOT2 7702 10 ENTER Resumes normal readings since the Model 7702 does not have card specific features t...

Страница 31: ...hundreds digit is the slot number and the remaining digits denote the channel number on the card see Channel list parameter located at the bottom of Table 4 Table 3 Channel description Channels Descri...

Страница 32: ...Values are rounded to the nearest mV 12VDC 12VDC Table 4 Output subsystem commands Command Description Default OUTPut Set the output of a 7706 channel VOLTage NRf clist Forces the analog output of th...

Страница 33: ...NSe 1 Subsystem Commands to perform Model 7706 specific operations are listed in Table 5 Table 5 Sense1 subsystem commands Command Description Default SENSe 1 Path to the SENSe 1 commands TOTalize Pat...

Страница 34: ...up for two hours before proceeding Use the following steps to verify the Model 7706 analog output channels 1 Connect CH23 H and L outputs to CH1 H and L input terminals respectively 2 Connect CH24 H a...

Страница 35: ...limits 17 Set analog output 2 to 10V a Open the SHIFT CARD menu press SHIFT CARD b Key in analog output for AOUT2 10 000V 18 Verify analog output reading is within stated limits 19 Open channel 2 pres...

Страница 36: ...uts G and G open gate always 3 Set the threshold jumper to the TTL position J2 closed 4 Close and lock the Model 7706 cover NOTE Make sure the Model 2700 is OFF before installing the Model 7706 5 Inst...

Страница 37: ...3 Verification Figure 25 Verification Totalizer connections 50 Coax Cable Function Generator Function Output TE2 TE3 TE1 J3 TE4 TE5 TE6 TE7 J2 TE3 J2 Gate Gate IN IN Threshold jumper J2 closed 1 2 TTL...

Страница 38: ...that could affect calibra tion accuracy Allow the Model 2700 to warm up for at least two hours 1 Connect the Model 7706 to the 7798 250B Calibration Extender Board 2 With the power off install the Mo...

Страница 39: ...ion temperature measured in step 4 11 Send the following commands to save calibration and lock out calibration CAL PROT CARD1 SAVE CAL PROT CARD1 LOCK Front panel Model 7706 analog output DAC calibrat...

Страница 40: ...OCK 6 Enable calibration by sending the CODE command For example the default command is CAL PROT CODE KI002700 7 Initiate calibration by sending the following command CAL PROT CARD1 INIT 8 Calibrate t...

Страница 41: ...es card had been calibrated RCOunt Reset card calibration count to 0 DATE Request card calibration date SAVE Save cal constants to card EEPROM LOCK Lock out calibration LOCK Request cal lock state 0 l...

Страница 42: ...ocedures over the bus This command must be sent to the unit before sending any other Model 7706 calibration command The default calibration code is KI002700 Example CAL PROT CODE KI002700 Send default...

Страница 43: ...Tected CARD1 INITiate Purpose To initiate Model 7706 calibration procedures Format CAL PROT CARD1 INIT Parameter None Description The INIT command enables Model 7706 calibration when performing these...

Страница 44: ...ck state SAVE CALibration PROTected CARD1 SAVE Purpose To save calibration constants in card EEROM after the calibration procedure Format CAL PROT CARD1 SAVE Parameter None Description The SAVE comman...

Страница 45: ...to cool down After turning on the power during the calibration procedure complete the procedure as quickly as possible to minimize card heating that could affect calibra tion accuracy Example CAL PRO...

Страница 46: ...s the temp parameter during calibration NOTE Before calibrating the temperature on the Model 7706 make sure that power has been removed from the card for at least two hours to allow card circuitry to...

Страница 47: ...ror 408 100k 2 w zero error 463 100 vac full scale error 409 10M 2 w zero error 464 750 vac zero error 410 10M 2 w full scale error 465 750 vac full scale error 411 10M 2 w open error 466 750 vac nois...

Страница 48: ...n step To use OPC to detect the end of each calibration step you must do the following 1 Enable operation complete by sending ESE 1 This command sets the OPC operation complete bit in the standard eve...

Страница 49: ...he back of this manual and include it with the instrument Carefully pack the instrument in the original packing carton Write ATTENTION REPAIR DEPARTMENT and the RMA number on the shipping label Compon...

Страница 50: ...R27 RES 4 99K 1 125mW METAL FILM R 391 4 99K R28 32 34 39 59 63 73 74 76 77 RES 220 5 125MW METAL FILM R 375 220 R29 R86 R87 RES ARRAY 4 4 3K 5 0 125W TF 276 4 3K R31 R38 R40 RES 475 1 100MW THICK FI...

Страница 51: ...EEPROM LSI 212 U33 IC 8 BIT MICROCONTROLLER LSI 242 U4 U5 IC SCHMITT TRIGGER NAND GATE IC 950 U6 U10 IC 3 TO 8 LINE DECODE 74ACT138 IC 654 VR1 VR2 DIODE ZENER 12V MMSZ12T1 DZ 112 Y1 CRYSTAL CERAMIC RE...

Страница 52: ...48 Model 7706 module Figure 26 Component layout Side 04...

Страница 53: ...49 Replaceable parts Figure 27 Component layout Side 01...

Страница 54: ...ce DMM 1 year 5 C 0 15 19mV 90 day 5 C 0 1 19mV 24 hour 1 C 0 04 19mV TEMPERATURE COEFFICIENT 0 015 1mV C WRITE SPEED 50 s TOTALIZE INPUT Channel 25 MAXIMUM COUNT 232 1 TOTALIZE INPUT 100kHz max risin...

Страница 55: ...e 65 82110 Germering 089 84 93 07 40 Fax 089 84 93 07 34 GREAT BRITAIN Unit 2 Commerce Park Brunel Road Theale Berkshire RG7 4AB 0118 929 7500 Fax 0118 929 7519 INDIA Flat 2B Willocrissa 14 Rest House...

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