Digital output pulse for Strobe light

Leonardo Castro

Posted on 26.02.2017 02:58

Hi, I've been trying to command a strobe light base in the frequency speed of a fan (DI).

I use the counters, without any issue to acquire the speed, but once I try to command my digital output base in the frequency, I have random issues, sometime the command was skipped, I've been trying different setting in the setup of my DO channel, sample rates, frequency dividers from a math channel. But still have a longer or small pulse from what I expected.

I think this issue is related to a synchronization trigger, but even is I use the DI and sent it to DO, is there any way to solve this kind of issues.

Notes: Dewesoft X2 SP6. SIRIUSi-CD

The max speed will be over 4000 RPM with 2 blades (133.33 Hz).

DEWESoft Support
Technical support
Posted on 07.03.2017 07:38


I believe that you're already working with the US support guys regarding the issue, but I'll just post a short overview on the topic.

DEWESoft is currently unable to do "real time control" to the full extent. This is something that's planned for the future, but is only usable to a certain degree in its current state. You can send out some pulses or waves but they will all come with drawback in the form of a delay or a poor form. Since you're only trying to send out pulses, then your best bet is to use A/D out, as you've already discovered. I've made a quick test using the sync port and rerouting my output to an AI channel, and I can reduce the delay to about 13 ms, which gives you a "frequency" of 77 Hz, so about half the speed that you would like to get. I think that this response time is the best that we can currently do.

The performance is dependent on the sample rate (the higher the better), the application process priority and the acquisition update rate (if your DO channels are related to other inputs). I've attached a picture of the "maximum" performance oriented settings. I would strongly recommend to revert the acquisition update rate back to the default 50 Hz for all other applications.

Attached files:
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