Keysight DAQ970A Guide D'utilisation page 196

3 Features and Functions
DAQM903A 20-Channel Actuator/General-Purpose Switch Module
This module contains 20 independent, and SPDT (Form C) latching relays. This module can switch 300 V, 1 A (50 W
maximum switch power) to your device under test or to actuate external devices. Screw terminals on the module
provide access to the Normally-Open, Normally-Closed, and Common contacts for each of the 20 switches. This
module does not connect to the internal DMM. Use this module for those applications that require high-integrity
contacts or quality connections of non-multiplexed signals.
A breadboard area is provided near the screw terminals to implement custom circuitry, such as simple filters,
snubbers, and voltage dividers. The breadboard area provides the space necessary to insert your own components
but there are no circuit board traces here. You must add your own circuitry and signal routing.
You can close multiple channels at the same time on this module.
The channel CLOSE and OPEN commands control the state of the Normally Open (NO) to COM connection on
each channel. For example, CLOSE 201 connects the Normally Open contact to COM on channel 01.
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.
196 Keysight DAQ970A/DAQ973A User's Guide