Digital I/O
Transition from Legacy DAQ to DAQmx for writing to digital ports
Hello,
I have written code in LabWindows/CVI that controls our devices with static TTL level BCD outputs, and then read the two TTL feedback lines. Up until now, we utilized the NI-6503, 24 line DIO card and the Legacy DAQ “WriteToDigitalPort” and “ReadFromDigitalLine” commands. e.g.:
WriteToDigitalPort (1, "1", 8, 0, 0x01); //Output BCD 0001 to low bits on Port 1
ReadFromDigitalLine (1, "0", 0, 8, 0, &doneFB1); //Read Done feedback line 1 on Port 0
Each device requires four BCD inputs, so I was able to control two devices per port. We utilize two lines of Port 0 for each devices feedback lines. This allows control of four devices per DIO card. We would like to transition to the USB version of the 24 line DIO (NI-USB-6501), which requires the DAQmx driver. I have updated our version of CVI to allow DAQmx commands, but I’m not sure which of the DAQmx Digital I/O functions would be comparable to the legacy “WriteToDigitalPort” and “ReadFromDigitalLine”. In addition, to be completely honest, the whole “DAQmx Task” thing has me a little confused.
Definitely getting a feeling of “this used to be so simple…”.
Any suggestions would be appreciated.
Thanks,
John
