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Gaby D.
11-08-2009, 06:14 AM
I'm trying to set up one of those for use in a school project.
From what I was told, given a signal of 5V it'll open the valve fully, and at 0V it'll close. So, 2.5 would open it halfway. You can choose thresholds of 0-10V, 0-5V, 5-10V, or 4-20mA.
We're trying to make it so that when the temperature of water raises too high, the actuator will open the valve so cold water can come through, using some IF/THEN statements.

But, how would we tell the actuator to open it more than 0%, but less than 100%?
We figure we'd set up a bunch of pins and assign them to different voltages, but how would we tell the boebot to give out a signal on a certain pin thats less than the 5V it gives out?
I could have sworn there was a command for that, but I'm not finding anything variable other than FREQOUT.
If we can't do that, would setting up different capacitors on the related pins work?
The power supply we are using is rated for both 18/24VAC, and 1000mA (the actuator, DuraDrive M133A01, runs off of VAC with a DC input).
The DC Power supply is 500mA, 12V.

We're all drawing a collective blank in regards to both wiring this thing and getting a program written, anything would help!
Thanks for all of your help,
Gaby D

Post Edited (Gaby D.) : 11/7/2009 10:36:12 PM GMT

W9GFO
11-08-2009, 07:56 AM
If you put two resistors of the same value in series from the output pin to ground, then connect the signal line of the valve to in between the two resistors, you will be supplying half the output voltage to the valve.

Search for "wiki voltage divider".

Also, PWM is often used...

Rich H

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The Simple Servo Tester, a kit from Gadget Gangster. (http://www.gadgetgangster.com/206)

Gaby D.
11-08-2009, 08:45 AM
Thank you, we did something just like that and now it works. :)
But alas, now we have a totally unrelated problem (programming related), so I'll be posting a new thread about that.
Mods feel free to lock this thread, if thats what you do 'round these parts.

Thanks!

Post Edited (Gaby D.) : 11/8/2009 12:57:19 AM GMT

$WMc%
11-08-2009, 10:42 AM
Gaby D.

PMW will do what you need. 0 to 5v. I would use a driver from the I/O pin to the valve positioner input. Something like the 2N7000 Nch. MOSFET or The LM358. Take a look
at Experiment #22 on pg 126 of the StampWorks manuel.

As far as direct control of the valve in a process, take a look at P.I.D. control. I've seen some programs (PID) written for the BS2.

__________Hope this helps________

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