pc-dio-96

[Joe_H]

I have A PC-DIO-96 card and my dilema is that when I write all outputs low and then try to read them back The outputs read High. Why is that?

[srm@viewpointusa.com]

If you are reconfiguring your port in order to "read" the port, the port will be truely reconfigured as read inputs with the default state being pulled up.
If you use the same task ID that was generated from the "write" config in the read port function, you will be able to readback the written value.

[Joe_H]

Thanks for all your help. I'm Not that great with IO. It works just like you said. So now all I have to do is create a task then write zero's to it at the beginning of my program. then it should work correctly right.

thanks
Joe

[Jeremy_C]

Stu is correct is his explanation of the behavior. However, if the port is configured for output, you want to make sure you don't drive any of those lines with an external device. Otherwise, you can damage the board. It almost sounds like you are wanting to do a digital input operation with a set power up state. If this is the case, you can define what state your board powers up in. Refer to page 3-9 of the PC-DIO-96 user manual linked below.

PC-DIO-96 User Manual