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2-34 Close/Open Switching Module Channels Model 2700 Multimeter/Switch System User’s Manual
Model 7700 switching module
NOTE
Connection and wiring procedures for the Model 7700 are to be performed by
qualified service personnel. This information is provided in
Appendix B
(Model 7700 Connection Guide).
Switching module capabilities
Channels 1 through 20 — The Model 7700 can multiplex one of 20 2-pole signals, or one
of 10 4-pole signals into the input of the Model 2700.
Channels 21 and 22 — The Model 7700 can multiplex one of two 2-pole current signals
into the input of the Model 2700.
CAUTION To prevent damage to the Model 7700 switching module, do not exceed
these maximum signal levels:
Channels 1-20: 300VDC or 300V RMS (425V peak) for AC
waveforms, 1A switched, 60W, 125VA
Channels 21, 22: 60VDC or 30V RMS, 3A switched, 60W, 125VA
NOTE System channel operation — Of the 22 measurement channels, only one
channel (or channel pair) can be closed at the same time. When you close a
channel (or channel pair), all other measurement channels will open. The user
has no control of channels 23, 24, and 25. The open/close state of these channels
are determined by the selected function.
The Model 7700 has six temperature transducers to monitor the cold junction temperature
at the screw terminals. For temperature measurements, this internal reference junction
allows thermocouples to be connected directly to the screw terminals of the module.
When the Model 2700 is on the DCV, ACV,
Ω
2, CONT,
Ω
4, FREQ, PERIOD, or TEMP
function, channels 1 through 20 are available. When on a current function (DCI or ACI),
channels 21 and 22 are the only available channels.
The Model 7700 can accommodate 4-wire measurements by using channel pairs. Primary
channels 1 through 10 become paired to channels 11 through 20. For example, with the
Ω
4
function selected, channel 1 becomes paired to channel 11. For example, when you close
channel 1, channel 11 will also close.