Undefined initial DA value on NI hardware

[MichaelHuth]

After power up on starting the first acquisition the initial DA value on the NI channels is undefined.

In a loopback configuration this can be seen as random amplitudes of the first ADC value.

Also related is that the DA channel voltage is not set to zero after an acquisition, but stays at the last value.

Considering the case of an unassociated DA channel and TP during ITI, the unassociated DA channel is not running during ITI and stays at the last voltage set.

• Initialize the DA channel output voltage on device locking.
• define how DA voltage should behave after a stimset and after an acquisition.