07-27-2007 02:38 PM
The PWM is really the key. Unless you need immediate and/or high-precision adjustments to the PWM duty cycle, the suggestions here about hardware-timed DO will likely be more sensible than the 8-counter idea I posted earlier. (Not to mention the fact I'm not sure my 8-counter method will work).
-Kevin P.
07-27-2007 03:33 PM
07-28-2007 11:07 AM
07-30-2007 09:43 AM
No, the E-series boards only support software-driven timing for digital I/O. Seems awfully unlikely you could achieve sufficient timing reliability that way.
-Kevin P.
07-30-2007 09:57 AM
07-30-2007 10:55 AM
No, the 6601 digital I/O only supports software timing. You might be able to use it to test out the older idea I threw out there though -- using the Pause Trigger feature to support variable PWM. If it works, then you'd have an additional option for moving forward on the project -- another 6601 would provide the additional 4 counters you'd need for a total of 8.
The best choice depends on your overall needs & budget. If you don't need to vary the PWM freq and/or duty cycle on the fly, I'd think an M-series board would be most peoples' best choice because of its versatility. Maybe consider the 6221 or 6251?
-Kevin P.
05-04-2014 07:49 PM
High side switching is standard in a 3 phase H-Bridge
Only two are really active at one time mainly because you need a full path from one Hi and one low. This is typically a grounded phase operation;
The diagram from https://www.basilnetworks.com/article/hybrid/powerbridge.html explains the two out of three phases being used and the third is grounded.
To create a sine wave from pulses follow the PMBM web page https://www.basilnetworks.com/article/motors/brushlessmotors.html and set the the number of pulses from 0 to Pi for three phase points.
Sal Tuzzo
CTO Basil Networks