about "change detection" example

[zy9]

the change detection example VI in LV7.1, one VI "DIO start" can accept handshake "change detection" source, when check it's help, saying this mode only for 6534, but I have PCI 6518, the spec PDF saying it has "change detection", so how can I use the 6518 change detection ? is this the software "change detection" and the 6534 with HW "change detection" ? 6518 is much cheaper than 6534, if 6518 can do it, i would like to use it and I don't want the change detection takes more cpu.

[Abhinav T]

Hi zy9,

The 6518 supports hardware change detection. If you look at the Read Dig Chan-Change Detection.VI, this VI is meant for the 6518. Did you get any specific errors when running this example?

[zy9]

ok, no error, just wondering if I can use the "change detection" mode to implement a counter ? that will save us buying a counter board, if any change detected, just increas the counter +1 ?

we like to use 6518 implement 2 "HW change detection and 1 HW counter", because all of them HW, so cost very little CPU ? the main application running on the same PC.

[Nick_F1]

There is no counter on the 6518 so you can not implement a hardware counter unless you purchase a counter/timer board, but if all you have to do is keep track of the number of change detections detected, it is simple and does not take up much CPU.  Basically you have a wire that holds the value and every time a hardware change is detected, increment the value.