Agilent Technologies Switch/Measure manual General Purpose Switch Modules, Relays

6General Purpose Switch Modules

General Purpose Switch Modules

Use the general- purpose (GP) switch modules in your 34980A mainframe to route signals or control other system devices.

•The 34937A 32- Channel Form C and Form A GP Switch Module provides independent control of 32 latching relays:

•Twenty- eight Form C relays rated for 1 A at 60 W per channel

•Four Form A relays rated for 5 A at 150 W per channel.

•For power switching applications, the 34938A 21- Channel 5 A Form A Switch Module offers 20 Form A relays rated for 5 A at 150 W per channel.

Both modules contain armature- latching relays, and you can use these switches for device actuation, digital output, or combined with other switch modules to create flexible switching topologies. You can close multiple channels at the same time. These modules do not connect to the analog buses.

A temperature sensor on these modules triggers system interrupts when high- carry current- induced heat on the modules is excessive and sets the HOT annunciator on the front panel. This over- temperature situation generates an SRQ event when the factory- set 70 oC threshold is reached. It is up to the user to determine what, if any, action should be taken.

Reactive loads (those that include significant inductance or capacitance) can cause voltage spikes or current spikes during switching operations. The general purpose modules are designed for switching reactive loads. The optional 34937T and 34938T terminal blocks have solder pads for adding snubber circuits for the 5 A relays to reduce the reactive transients. See the drawings on page 170 and page 173 for the locations of snubber circuit pads and installation information about a snubber circuit.

A hardware jumper on each of the GP modules allows you to define the power- failure states for the modules’ 5 A latching relays. Depending on the position of the jumper, the 5 A relays will either open or maintain state when system power failure occurs. When shipped from the factory, the power- fail jumper is in “MAINTAIN” position (all relays maintain their present state when power fails).

N O TE	The 34937A has five 5 A relays, and the 34938A modules has 20
	5 A relays

WA RN I N G	Before changing the position of the jumper, remove external
	connections from the module. Wait five to ten seconds to allow
	the module’s internal capacitors to discharge.

164 34980A User’s Guide