04-13-2017 11:05 AM
I hooked up a 4 channel scope to the 4 resistive loads and measured the time delay between each turn on.
04-13-2017 11:25 AM
Here's the scan list command I setup... I actually used 8 channels at the same time in my final solution, not 4.
";ch24->com24&ch25->com25&ch26->com26&ch27->com27&ch28->com28&ch29->com29&ch30->com30&ch31->com31;~ch24->com24&~ch25->com25&~ch26->com26&~ch27->com27&~ch28->com28&~ch29->com29&~ch30->com30&~ch31->com31;"
Then sent a software trigger command to enable this at the card level.
04-13-2017 11:34 AM
So it looks like you turned on 8 relays and then after they have all turned on, you turned them all off.
I wonder if you would have entered your command like this:
";ch24->com24&&ch25->com25&&ch26->com26&&....;~ch24->com24&&~ch25->com25&&~ch26->com26&&....
I bet it would have handled each relay in order. I wonder how much time it would take to wait for the debounce though?
04-13-2017 11:43 AM
Now I may be understanding it wrong, but looking at the spec sheet of the NI PXI-2567 under Dynamic Characteristics, it says that single channel operation time (typical at 25 deg C) is 60us.
And i don't need to open AND close the channels all within 5ms, I just need to open them in order within 5ms.
04-13-2017 12:01 PM
Sorry, I'm remembering this all in pieces. That scan list was setup for two software triggers. We send the first software trigger to turn all 8 channels on, wait 100ms, then send another software trigger command to turn all 8 channels off.
That's why it looks like I turn them all on then all off.
I didn't have to worry about debounce since I was using the card more like a solid state switch instead of a relay coil driver. Debounce spec would be a parameter of the relay you're driving, not the FET driver that's energizing the coil.
04-13-2017 12:05 PM
its okay. So really, you just turned on 8 different channels "at the same time" within 10us, waited, and then turned them all off, correct?