Write HIGH(5v)-LOW(0v) to DAQPAD-6020E (DAC0_bit0-bit7)every *Time* configured in a buffer

[brucelee]

I'm working with an Apliction,to control 2 step motors from DAQPAD 6020E...When i run my program i get two Array Subset. One with high and low (1 & 0), and one with different wait times. Such as 1 ms,1,56 ms 6,59 ms...and so forth.That means that i need micro second accurasy.What i use these times to is to wait ex. 1ms, and then write to, two channels (or more), High to the first and low to the second channel.Then again wait the specified time from the array subset ex.1,56 ms and write to the channels when that time has passed.These two Array subset wil be running continuously alwyas starting from index [0] to end of Array.I've tried to use Wait until next ms multible.vi
in a for loop, where i have 1/1000 at the input to the timer,but its not working as the timer is ment for ms.Please help me, i'l appriciate any help or suggestions for my problem, thks. & regards

[RIO-Todd]

Hey Brucelee,

You won't be able to get microsecond resolution with the digital I/O of the 6020E. The digital lines of the 6020E are unstrobed (non-hardware timed) and the wait functions in LabVIEW have a resolution of 1 ms.

I would suggest looking into our high-speed digital devices. The NI 653x devices can perform strobed (hardware timed) digital I/O in the MHz range. Therefore, they could give you the microsecond accuracy you're looking for.

The other option would be to use the two counter/timers on the 6020E to generate the digital signals. These counter/timers use a 20 MHz clock and have microsecond accuracy. The only problem is that you only have two counters. If you are needing more than two channels, a NI 653x device would be perfect. I've
linked to the 653x products below for your reference.

High-Speed Digital I/O Devices
http://sine.ni.com/apps/we/nioc.vp?cid=1103〈=US

Regards,

Todd D.
NI Applications Engineer