A/D board problem

Discussion in 'General Electronics Chat' started by samik, Jun 28, 2011.

  1. samik

    Thread Starter Member

    Nov 9, 2009
    Hi all,
    This is regarding UEI daq board PD2-MFS-8-800/14DG ( see pd2-mfs.pdf). This board has 8 input channels which can be used in differential mode. I was using 5 channels in differential mode ( AIn 1 to Ain 5 )and it was working fine. But later while using all the 8 channels in differential mode ( AIn 0 to Ain 7 ) it gave problem ( all the channels are showing 0.2 or 0.1 v instead of 1.2 or 1.3 V as they should ). After checking with a function generator I found that the problem can be solved by putting a 50 ohm terminator on the Ain8 channel of the PD-BNC-16 ( the bnc connector board which is connected to A/D board (see pd-bnc.pdf)) . Now I do not know why this is happening. So any help in this regard will be deeply appreciated.
    One important point about the PD2-MFS-8-800/14DG board ( can be found in pd2mf_manual.pdf) is that,it is capable of simultaneous sampling and uses sample and hold amplifiers for this purpose.