09-09-2008 07:25 AM
the user manual (6602) talks about pad synchronization. I need six counters to start generating PWM - Signals at the exact same point of time. An external trigger should be used. As pointed out in the user manual, the external trigger is connected to PFI 38, the counters have PFI 38 selected as their gate. I've managed to trigger the PWM Signals, but they are NOT synchronized. In fact I could observe quite a huge time delay between the PWM - Signals. Can you tell me, which bit i need to change on register-level ? Pad Synchronization is not mentioned in the RLPM.
09-17-2008 03:12 AM
first I want to ask you which API you are using, NI-DAQ or NI-DAQmx?
If you use DAQmx, you can enable the "Digital Synchronisation"-Property to enable the synchronisation called
pad synchronisation in the 6601 manual. You can find the details here.
If that is not sufficient, let me know.
Marco Brauner NIG
10-10-2008 04:08 AM
thanks for your reply and sorry for my late answer. I've been bussy I'm neither using NI-DAQ nor DAQm-stuff, I have to use comedi, since I need a HIL - setup using RTAI, matlab .... That's the reason why I'm posing my questions on the DDK board. I need some information on RL. I've tried your link, but unfortunately it is broken. Can you post it again ?
10-10-2008 10:28 AM
ok, I see. Forget about the link I´ve posted. It´s about DAQmx.
I´ll check out if i can help you with RLP on the 6601. We don´t provide register level programming
assistance normally, we only provide the manual which is here.
10-13-2008 05:03 AM
that would be really nice. I allready hat a look at the RLP - manual, but pad-synchronization isn't mentioned. It is mentioned in the NI 660x User Manual, without telling how to enable it.
02-14-2010 12:50 PM
I'm not sure if pad synchronization will address Nico's symptoms. As the manual points out on page 13 (Ch 2, pg 2) , pad synchronization normalizes propagation delays in the board from the I/O pins to the counters' inputs on the TIO ASIC. However, propagation delays are never more than the period of the fastest timebase on the board (otherwise pad synchronization couldn't be called a feature ;-). Since Nico mentioned seeing "quite a huge time delay between the PWM - Signals", I believe he's facing a different kind of synchronization problem.
My question is: do any of you folks observe asynchronicity due to propagation delay? In other words, is the maximum time between one PWM starting and a second PWM starting equal to the period of the clock on the counter's source? You may just need to use the same signal (provided either externally or internally) to arm-start the counters instead .
 660x User Manual
 What are the 3-bit field choices for Hw_Arm_Sel in PCI-6601
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