Correct setup for SC-2040 in MAX

[kenkar]

I have recently acquired the simultaneous track-and-hold accessory SC-2040. I have some questions on how to configure it in MAX. Under the device tab in the configuration for my device PCI-6070E (PCI-MIO-16E-1), there is accessory tab in which I can specify what accessory is connected to the PCI-6070E. Should I select SC-2040 in the accessory tab? Once it has been selected, what effect does it have on the signals being sampled? There are other selections for specifying the gain that is set in SC-2040 for each channel, should I input the correct settings in? I found that if I input the gains in, the values of the virtual channels actually corresponded to the pre-amplified (raw) values. Were these normal? This leads to a further question
on setting the correct range for each virtual channel. Should I specify the range for the raw signal or the amplified signal? From my understanding, the range setting will determine what gain the DAQ card will use. I think it is inefficient if the signal could be amplified in one stage but is done in two stages.

There is a message stating that if SC-2040 is selected, the PCI-6070E is automatically selected to DIFF mode. Does it imply that I also have to select DIFF mode for all my virtual channels?

In general if I want to use NRSE mode, do I need to set both my device, PC-6070E and all my virtual channels to NRSE in order to sample them correctly? What would happen if the device and the virtual channels are set differently, e.g. DIFF in the device and RSE in the virtual channels? Would one setting overrides the others? What is the effect on the accuracy of the acquired data?

[Russell]

I'll try not to miss any of your questions:

Should I select SC-2040 in the accessory tab? Once it has been selected, what effect does it have on the signals being sampled?

Yes, you should select SC-2040 as the accessory. This helps let MAX know what other settings should be made. Often times this isn't much but, still.

There are other selections for specifying the gain that is set in SC-2040 for each channel, should I input the correct settings in? I found that if I input the gains in, the values of the virtual channels actually corresponded to the pre-amplified (raw) values. Were these normal?

Yes, this is correct behavior. Choosing the corresponding gains in MAX compensates for the gain so that you read the raw voltages. Also, the
range you specify in MAX should be the range of the signal that hits the DAQ board, so it should be the value after the SC-2040 module.

So, since you have an SC-2040 you can do all of your amplification in one stage on the module itself if you want. I disagree, sometimes a two stage gain can be useful, but that's besides the point.

Does it imply that I also have to select DIFF mode for all my virtual channels?

Yes. Though I suppose you can change the referencing mode on a per-channel basis, I wouldn't recommend this. In your case you should make them DIFF.

Hope this helps,

--Russell

[kenkar]

A minor question, if I can do all of the amplification in one stage, do you think it is advantagous to set the ranges of all the virtual channel to be the same? I presumed this will then make the DAQ card to use the same gain for all channels and hence minimise the setting time. Am I correct?