I am having problems setting the gain programatically from Labview 6, using the Hardware Config vi, for a PCI6110E DAQ board.

[Jo]

Changing the "gain" (part of the "alternate input limits" cluster) appears to affect the group settings, but when I pass a signal outside the supposed new voltage range, the signal doesn't clip as I would expect. This doesn't happen when I use MAX (where clipping is clearly visible), but unfortunately that is not an acceptable long-term solution. Any thoughts? I am only using allowable gain settings for the 6110E.

Additionally, I am saving my data in hsdl format, and to get the actual true voltage from the binary numbers (after uncompressing and converting back to standard binary format) I need to multiply the final number by the gain. Shou
ld this be correct? I thought the "scale multiplier" (part of "group settings cluster") compensated for "gain", but it doesn't seem to do so. Is this part of the same problem?

[Spencer S.]

Greetings,

I just tried setting the gain using the "alternate input limits" with my 6110, and I was able to see the clipping with a gain setting of 50.0 and a 2 V peak-to-peak input signal. I did notice that if I used the "input limits" input to Hardware Config.vi, set the input limits back to 0.00 and 0.00 (default), and then set the gain, it was ignored. With regards to the multiplier, that sounds correct to me.

Good luck with your application.

Spencer S.

[Jo]

Thanks Spencer. I do call Hardware Config.vi in several different places, so maybe its the multiple calls that is stuffing things up. I will investigate further.

As for the multiplier, which bit sounds correct? The fact that I have to multiply by the gain, or that it should take this into account automatically and therefore not have to muliply by the gain (which is what the default hsdl code does). What do you do to convert from binary to real?

Thanks for your help,
Jo