Can I measure 2 differential channels on a single SCC-SG24?

[jmclean]

I am trying to use a single SCC-SG24 module to excite and measure the output of 2 pressure transducers.  The module is installed in the ACh2 position of an SC-2345 carrier. When I configure the module through 'custom voltage with excitation' in MAX, I can set the terminal configuration of ai2 to differential. However, the other channel of the module, ai10, can only be set to RSE or NRSE; the other options are greyed out. I want both channels to be set to differential. Can I configure the SCC-SG24 to measure 2 differential channels on a single SCC-SG24? Thanks.

[Otis]

Hi,

I did a little looking into the DataSheet for SCC Modules, and I found the following schematic.

As you can see there 2 instrumentation amplifiers that make it to where your measurements are really differential, and then mapped to the NRSE lines in the SC-2345.  If you were to set up the DAQ board for differential it would simply read the difference between one pressure transducer and the next.  Long story short, you set up the DAQ board for NRSE for all of the channels, the SCC-SG24 makes it to where you are really taking a differential measurement.  Everything works quite simply in the end.

Regards,

Message Edited by Otis on 10-11-2005 12:56 PM