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Chapter 7 Plug-in Modules
44470D 20-Channel MUX Module
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7
44470D 20-Channel MUX Module
The Agilent 44470D Relay MUX Module provides 20 2-wire channels
(latching relays) to switch both High (H) and Low (L) input signals to a
common bus. The individual relays on this module are rated at a
maximum voltage of 250 volts with a maximum current of 2 amps dc or
ac rms.
The module exhibits low thermal offset characteristics, making it ideal
for precision low-level measurements. However, since no thermocouple
compensation is included, temperature measurement errors may occur if
you use this module to switch thermocouples.
The 44470D can be operated in one of two modes: single channel break-
before-make (BBM) or multiple channels closed at the same time.
Specifications for the 44470D are given on page 331.
44470D Simplified Schematic
A simplified schematic is shown below. The 44470D consists of 20 2-wire
relays connected to a common bus. Channels on the 44470D are
numbered as 00 through 19 (CH00 through CH19).
L
H CH19
L
H CH18
L
H CH11
L
H CH09
L
H CH10
L
H CH08
L
H CH01
L
H CH00
L
H Common Bus
L
H CH19
L
H CH18
L
H CH10
L
H CH11
L
H CH00
L
H CH01
L
H CH09
L
H CH08
Common Bus
44470D Relay MUX Terminal Block