Keysight DAQ970A Guide D'utilisation page 193

DAQM900A 20-Channel FET Multiplexer Module
This module is divided into two banks of 10 two-wire channels each. All 20 channels switch both HI and LO inputs,
thus providing fully isolated inputs to the internal DMM or an external instrument. During 4-wire resistance
measurements, channels from Bank A (channel n) are automatically paired with channels from Bank B (channel
n+10) to provide the source and sense connections. The module has a built-in thermocouple reference junction to
minimize errors due to thermal gradients when measuring thermocouples.
TO PREVENT ELECTRICAL SHOCK
To prevent electrical shock, use only wire that is rated for the highest voltage to any channel. Before removing
a module cover, turn off all power to external devices connected to the module.
CAUTION WITH MULTIPLE SIGNALS
To avoid the possibility of multiple signal sources becoming connected together, we recommend when
multiplexing two or more sources they should be connected on separate modules or on separate banks of the
same module.
CAUTION WITH HAZARDOUS VOLTAGES
When any channel is connected to a hazardous voltage source, all channels in the module should be treated as
hazardous and all channel wiring in the module should be rated for the maximum voltage applied. Ther-
mocouples attached to any other channel on the module should have insulation rated for the maximum
voltage, or have additional insulation added rated for the maximum voltage and should be isolated from
conductive parts using a thermal compound or tape rated for the maximum voltage applied. Do not mount,
move, or remove any thermocouples when the device under test is connected to a supply source.
ENVIRONMENTAL HEALTH AND SAFETY
When any channel is connected to a hazardous voltage source, the instrument and the device under test
should be supervised, following local EHS practices to restrict access.
Keysight DAQ970A/DAQ973A User's Guide
3 Features and Functions
193