MCC USB-1808 may show incorrect output DAC values when driven from waveform generator

[sergeys21]

The Analog Output controls (Ao1 and Ao2) are designed to drive DAC, but not read the current output. If Analog Outputs are driven from Waveform generator, Ao1 and Ao2 do not reflect the change and one has no way to read actual current AO. Moreover, after Analog Outputs are driven from Waveform generator, Ao1 and Ao2 value do not show current outputs. One needs either the readback fields ("actual positions") similar to encoder readouts and a "sync actual-to-requested" button.

[MarkRivers]

If Analog Outputs are driven from Waveform generator, Ao1 and Ao2 do not reflect the change and one has no way to read actual current AO.

It is difficult to update the ao records to display the current output voltage during a WaveGen scan. It is impossible in One-shot mode, because as discussed in #34 the current point is not updated during the scan. In principle it might be possible in Continuous mode, using the Current point as the index into the waveform that was sent to the device. That would require updating the value of the ao record with that readback, without processing it.

Moreover, after Analog Outputs are driven from Waveform generator, Ao1 and Ao2 value do not show current outputs.

I have fixed this problem in commit c317107
The current analog output values are now saved at the beginning of the scan, and restored at the end.
This prevents the issue of the ao record values not matching the actual output voltage at the end of the scan.