Multiple AI channel reads with differant input limits

[Paul R]

I want to aquire two high frequency AI channel signals from my SCB-68 at the same time. The signal is coming from two seperate pressure transducers. One needs to be sampled at 2000Hz with a voltage range of -10V to 10V and the other sampled at 200000Hz with a voltage range of 0V to .12V. I have been using the AI Waveform Scan.vi to aquire the two channels. But that requires two seperate case structues and activating them in sequence.

[johnsold]

SCB-68 is just a connector block so it has nothing to do with your acquisition challenge. Some DAQ devices can be set up for different gains per channel, but others cannot. If your device cannot have different gains per channel, then you either need to do all the acquisition at +/-10 V and give up resolution on the other channel or use an external amplifier on the low voltage channel.

Similarly, most DAQ devices cannot sample two channels at different rates. Acquire both channels at 200 kHz and use decimation or other processing to reduce the data to the equivalent of 2 kHz for the slow channel.

Another option would be to use two DAQ boards and set the gains and sampling rates differently on each. The acquisitions could use a common trigger and with a sepa
rate frequency divider could have synchroized clocks if that is important.

Lynn