6110e: threshold control of STARTSCAN input signal

[kopperek]

I'm using the 6110e DAQ card in the external clock mode. The external clock (TTL) is connected to the PFI7 pin (and the trigger to the PFI0 - so this is typical configuration). I need to control the threshold level of the startscan signal and set it to lets say 3 Volts (low to high edge). Does anybody know how to do this using Labview (version 6.0)? I cannot find any information about controlling this parameter in the 6110e manual. It lools like it is possible to control the threshold for trigger signal (analog triggering), but how to do this for clock???

[Bharatinder Sandhu]

Hi:

You cannot control the threshold level of the clock. The external signal has to be TTL type and has to follow those specifications.

You can build an external circuit which generates a TTL pulse every time it recieves a the signal that goes beyond 3V and use this output signal as the external clock.

You can also, wire the external clock to PFI 0 or one of the analog input channels and use analog triggering to generate a trigger every time the signal goes above 3V from low to high. You can then use the Route Signal VI to route the analog trigger circuit output to the scanclock.

Regards,
Bharat Sandhu
Applications Engineer
National Instruments

[kopperek]

I understand. I cannot say I feel happy with that, I think I will try the external re-clocking circuit.

Thanks anyway.