Keithley 7708 User Manual - Model 7708
PA-744 Rev. C / 8-03
Model 7708
40-Channel Differential Multiplexer with Automatic CJC
User’s Guide
Keithley Instruments, Inc.
28775 Aurora Road
Cleveland, Ohio 44139
(440) 248-0400
Fax: (440) 248-6168
www.keithley.com
Introduction
The Model 7708 is a 40-channel differential multiplexer card with the following features:
• DC and AC voltage measurement
• 2-wire or 4-wire
Ω
measurement (automatically pairs switches for four wire measurements —
n
+ 20)
• Temperature applications (RTD, thermistor, thermocouple)
• Built-in cold junction reference
• Screw terminal connections
• Designed specifically for use with Keithley’s Model 2700, 2701, and 2750 system DMMs.
NOTE
All references to the Model 27xx apply to the Models 2700, 2701, and 2750.
WARNING
Before operating the Model 27xx with an accessory card, verify that the card is properly
installed and the mounting screws are tightly fastened. If the mounting screws are not
properly connected, an electrical shock hazard may be present.
Topic
Page
Introduction
Specifications ........................................................................................................................................................................
2
Operating instructions...........................................................................................................................................................
2
Card configuration
Description............................................................................................................................................................................
3
Card connections...................................................................................................................................................................
4
Wiring procedure ..................................................................................................................................................................
6
Typical connections ..............................................................................................................................................................
7
Connection log ......................................................................................................................................................................
9
Performance verification
Verification test requirements .............................................................................................................................................
10
Test considerations..............................................................................................................................................................
11
Verification limits................................................................................................................................................................
11
Recommended test equipment ............................................................................................................................................
12
Performance verification procedures ..................................................................................................................................
13
Calibration
Recommended test equipment ............................................................................................................................................
23
Extender board connections................................................................................................................................................
23
Model 7708 calibration .......................................................................................................................................................
23
Replaceable parts
Parts list...............................................................................................................................................................................
24
Ordering information ..........................................................................................................................................................
26
Factory service ....................................................................................................................................................................
26
Component layout...............................................................................................................................................................
26