Need More PWM's

[RJE]

I built a water cooling system for my gaming rig that is controlled by several programs. I would like to get this all under DaqFactory with Labjack hardware.

I've decided to use PWM to control linear voltage regulators to control fan/pump speeds and the voltage my Tecs get. This seems to be the best as it keeps the tach signal alive than using straight PWM. I bench tested it and it works well.

I need at least 8 PWM signals at 100 Hz and I'm not sure the best method to achieve this along with being cost effective. I have a spare U3 not being used so I could get another 3 for the built in PWM timers or can I get 100 Hz PWM out of a standard output?

Thanks for any ideas.

Randy

[AzeoTech]

You can probably get 100hz out of the output, especially since, truthfully, you aren't setting the output 100 times a second, but rather on 2 times a second, you just might be turning it on then 1/100 of second later, turning it off for 99/100's of a second. The easiest thing to do is just try it.

[RJE]

That's true and I will give it a try.

But I can't seem to find the way to script 'turn output on/off', I don't want to use a channel for these outputs.

It's there somewhere in the manuals but I can't find it or realize it, probably right in front of me!

[AzeoTech]

Why wouldn't you use a channel? Then you can just do:

mychannel = 0

or

mychannel = 1

and it will take care of the rest. You can set History to 1, and not log it. Timing will be 0 on outputs.

As for scripting it, you'd have to call the UD directly using the various functions as described in the DAQFactory-LabJack application guide. If you don't use channels, then you have to use device specific commands.

[RJE]

I've found all the commands in the LabJack app guide and have tested them and the test scripts perform well. This is called reading the manual real good!

As for the PWM, you have to run at a higher frequency than 2 per second so it won't be noticeable. Like turning a LED on/off twice per second, you would see it. Do it 30 times per second and you wouldn't see it.

The goal here is to use LabJack I/O and DaqFactory channels wisely. I have 10 temp sensors, 1 humidity sensor, 4 flow meters, 4 pump tach signals, 8 fan tach signals and 2 liquid level sensors for inputs. Outputs I need PWM's for fans, pumps and 4 banks of 3 tecs in serial.

If I was rich I'd just use a nice industrial controller or 6 or 7 U3's and a DaqFactory license with unlimited channels. But alas I'm not.

Now only if this was for the government.

[AzeoTech]

Sorry, but I can't exactly give you support on ways to get around DAQFactory licensing limitations! However, you should be able to use low level LabJack UD commands to control the LabJack without channels. It will be a bit more painful and ugly than channels.