How do I get a digital output (+5V) from a PXI-6704 if it is connected to a SCB-68?

[HokieTodd]

I would like to be able to use the Digital output to send TTL signals to a controller to overide any analog inputs it is receiving.

[JeremyB]

Assuming you are using LabVIEW, it is possible to update the state of the individual digital lines (8 in total DIO0-7) on the PXI-6704 using the Write To Digital Line VI. With this VI you simply specify the line number (0-7) and the state (T/F).

Alternatively if you wish to update all 8 lines at the same time, you can use Write To Digital Port. In this instance the number you pass to the VI will determine to state of all 8 bits. For example, pass the value 141 (decimal) = 8D (hex) = 10001101 (binary) will set lines DIO0,2,3,7 HIGH and the rest LOW.

You can also create virtual channels for individual lines or the complete 8-bit port using the Measurement & Automation Explorer.

Jeremy

[JeremyB]

Forgot to mention that the DIO lines can be found on pins 2-9 of the SCB-68 with reference to DGND (several available including pin 35). The PXI-6704 User Manual has more information about signal connections and considerations for hooking these lines up to external equipment.

Jeremy