How can I use PWM to control a Solenoid Valve through a PLC?

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kunalv

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I am looking at controlling the flow-rate of one liquid through a Solenoid Valve in a closed loop system, which takes input from another stream of liquid.

Objective is to mix the two liquids at the right concentration downstream.

I was able to source a PWM enabled valve, but how do I send the PWM signals to the valve? I have read about Controllers and Drivers, but don't understand too much as I am not from an Electronics background.

Any guidance would be appreciated. Thanks
 
This is likely not a NEC issue, probably for 2 reasons, your location (India) and PROBABLY the voltage (12VDC or 24VDC with over 90% of the PWM I work with.

The valve manufacturer probably offers a PWM module designed for the valve. That is likely your best option as the PWM drive and dither frequencies will be optimum. But there are "universal" modules available. You need to know the current requirement and want to know the optimum frequency for the PWM. There will also be dither (a low frequency modulation of the PWM) with frequency and amplitude "requirements".

Given that, you need to write the control algorithm for the PLC. The PLC will output an analog voltage, commonly 0-10V or 0-5V, to the PWM module.

Like other computer equipment, PLCs have gotten faster. Some offer the ability to output PWM directly. Depending on your system (the mixed liquids), I've seen even basic PLCs setup to, with no accessories, do 0-100% as no more than 0.1 second to 10.0 second "pulses.

So give us more information of your engineering and needs, and we'll be able to give real help instead of the wishy-washy worthless stuff I've given so far.
 
A typical solenoid valve is not designed for partial flow operation, but apparently the valve you refer to is, given that the manufacturer advertises a PWM module for it. My question would be whether it is a very rapidly acting valve which would be oscillating between full open and full closed or would be, in effect, responding proportionally to the effective value of the applied voltage waveform.
Can you give us a part number or catalog reference?
 
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