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PWM / transistor output connections

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Can someone please shed some light on a problem for me?!

I am fairly new to visilogic / unitronics and I am trying to control a proportional valve with a PWM block linked to an output. I am insure if I have the valve connected to the correct terminals of my V570.

I have a V200-18-E3XB snap in board.

I have a 24vdc +ve connected to the common connector of the digital output connector block.

+ve terminal of the valve connected to O6

-ve terminal of valve connected to O0

I'm not sure that this is correct?

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Hi Emil

The valve we are using is a burkert 2865


We do not have the controller for this valve that converts a 4-20 signal to a pnp PWM control, we would like to link the valve directly to the V570 and use the pressure transmitter also linked to the V570 to control the valve.

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Hi Russ,

It seems good idea to use V570 to drive the valve proportionally via PWM.

Some tips:

If you have Snap In module V200-18-E3XB, you must use one of the transistor outputs. It can be in PNP mode. You need ot use DO0 or DO1.


You need to supply first 24V DC for transistor DO - to pins V1 and 0V. Please see chapter "Wiring power supplies" in the beginnning of page 4 of the spec. You can find the spec in our site www.unitronics.com > Support page > Technical Library.

It seems you need to connect +Ve of the valve to O0 or O1 (see "Transistor outputs" chapter in page 5, follow PNP wiring diagram on left).

-Ve of the valve needs to be connectged to 0V of 24V power supply.

You must connect reverse diode to the valve. I recommend you 1N400x or even more powerful (1.5A or more).

Then, in Hardware configuration of your project, you need ot set High Speed Output (HSO). I recommend you to set constant frequency at 400 Hz and to change duty cycle from 0 to 1000. This way you will get the valve opening proportionally 0-100.0%.

Please let me know if you need further help.

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