9207 com port

[m3rv89]

Hi, i am new to NI products. Recently I am worknig with NI 9207 Analog 16 Channel Input Module.

I encountered some problems.

1. There are four COM ports - PIN9, 10, 28, 29. I would like to know whethere are they all connected to the same ground? 

2. The input circuitry displayed two amplifier diagrams. One is of instrumentation amplifier and the other is  of amplifier. What is the difference?

[RavensFan]

1.  Yes.  Of course.  Why wouldn't they be?

2.  The first 8 channels are going into the "instrumentation amplifier".  They are the 8 channels set for differential mode in voltage.  The second 8 channels are going into the "amplifier" are set for current readings.