Model 7702 - Connections And Wiring; Connection Information - Keithley 7702 User Manual

Model 7702 – connections and wiring
The Model 7702 is a 40-channel differential multiplexer module with the following features:
• 2-wire or 4-wire Ω measurement (automatically pairs switches for four wire measurements — n + 20)
• Two protected channels for current measurements (external shunts not required)
• Temperature applications (RTD, thermistor, thermocouple)
• Latching type relays (relays hold their position after power is removed)
• Screw terminal connections
• Designed specifically for use with Keithley's Models 2700, 2701, 2750 or 2790 Systems.

Connection information

WARNING The information in this section is intended for qualified service personnel. Do not
attempt to perform this procedure unless qualified to do so.
Do not exceed the maximum specifications for the Model 7702.
Connections to DMM functions are provided through the card backplane connector.
• Current provided for through two protected channels (Channels 41 and 42).
• INPUT connections.
• SENSE (Ω4 Wire) connections.
• AMP and LO common connections to the DMM are also provided.
Wiring procedure
WARNING The information in this section is intended for qualified service personnel. Do not
attempt to perform this procedure unless qualified to do so.
Use the following procedure to wire the Model 7702 module. Make all connections using correct wire size (up to 20 AWG).
Also, make sure to add supplementary insulation around the harness for voltages above 42V peak (see Figure 5).
WARNING All wiring must be rated for the maximum voltage in the system. For example, if 1000V
is applied to the front terminals of the Models 2700, 2701, 2750, or 2790, the plug-in
module wiring must be rated for 1000V.
1. Make sure all power is discharged from the Model 7702 module.
2. Access the screw terminals (see "Screw terminal access" located at the front of this document).
3. Using a small flat-blade screwdriver, loosen terminal screws and install wires as desired. (Figure 5 shows connections to
the Input and Sense).
4. Route wire along wire-path and secure with cable ties as shown.
5. Fill in a copy of the connection log and affix it to the module cover.
6. Close and lock the cover.
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