User manual

33 Chapter 3
Correct Connection
Incorrect Connection
Expanding Analog Inputs
You can expand any or all of the PCL-818HD/HG/L's A/D input channels
using multiplexing daughterboards. Daughterboards without D-type con-
nectors require the PCLD-774 Analog Expansion Board.
The PCLD-789(D) Amplifier and Multiplexer multiplexes 16 differential
inputs to one A/D input channel. You can cascade up to eight PCLD-
789(D)s to the PCL-818HD/HG/L for a total of 128 channels. See the
PCLD-789(D) user's manual for complete operating instructions.
The PCLD-774 Analog Expansion Board accommodates multiple exter-
nal signal-conditioning daughter boards, such as PCLD-779 and PCLD-
789(D). It features five sets of on-board 20-pin header connectors. A spe-
cial star-type architecture lets you cascade multiple signal-conditioning
boards without the signal-attenuation and current-loading problems of
normal cascading.
+
-
HIGH
LOW
+
Vin
-
+
Vs
-
Vcm GND
Vin=Vs
+-
+-
+
Vs
-
Vcm
HIGH
LOW
GND
+
Vin
-Vin=Vs+Vcm
+
-