Motorized control valves


Thread Starter


How the motorised control valve works? and can you please provide the wiring diagram so that I can understand the working and How many no. of IO's required for the functioning???
Provide a wiring diagram?

You should know by now that if you are interested in specifics about a instrument that you should go to the supplier or find what you are looking for on the internet. There are a lot of electric control valves on the market and all their wiring diagrams are different so you will have to find the right one for not just your make but also for your model.

They all basically have the same features though and that is that they can be supplied in just about any voltage, from 220VAC to 525VAC as the main supply. This is normally where the confusion sets in, in that the electricians now think this is part of their equipments since it has a supply of 400 or 525VAC. It's not. It is still a final control element in a control loop so it is a instrumentation function.

Electric valves can be used to do PID control or on/off control it all depends on how you wire it and which features you want to use. The possibilities are nearly limitless and I for one love working with them.

The only thing that you should really be worried about with these electric actuators is to maker sure you get the break away torques rating right when you place a order. The supplier will help you with that if you can tell him what the max differential pressure will be over the valve that you want to actuate. The rest is easy to do. You basically just wire it as you need it to work and then you do the limits as per the instruction manual. This in short entails turning the hand wheel to the open limit and save the parameter and then turn the actuator with the hand wheel to the close position and save the parameter and your actuator is ready to go. They look a bit involved when you get to them the first time but trust me they are really easy to work with and once you get to know them you will want to use them on all your control valve applications.
To answer the I/O
As Sam said, you need to look at the manual.

It might be just one 4-20 mA
migtht also require a 4-20 feedback
or it could just operate on discrete pulses with process feedback.
Or any one of a number of other schemes.

I know this didn't help
A major American manufacturer or two cannot provide wiring diagrams without the device's serial number.

I ran into this a year ago on a start-up. I got stuck waiting for the MOV to get wired. It isn't clear what happened to the original wiring diagram, but there was no diagram under the housing cover or in the shipping carton.

The first call to the manufacturer went into a queue. A couple hours later the guy calling back said that he couldn't state which terminals that model's AC power or control signal were on, it varied from unit to unit. I am incredulous.

But the presence or absence of standardized wiring diagrams does lead to difficulties with wiring motorized actuators.
> But the presence or absence of standardized wiring diagrams does lead
> to difficulties with wiring motorized actuators.

Most motorized actuators use a motor with two coils a capacitor with two limit switches, how hard can it be?
It's not a problem if one is clairvoyant, but I'm not.

Some MOV's use 4-20mA input.
Some provide 4-20mA output that follows feedback position.
Some still have slidewire feedback
power? 24Vdc? 24Vac? AC Voltage?
Some have position switches

The one I saw had about 20 terminals. Which were terminals were which?

Who wants to land power across a switch that's closed? Or wire the feedback incorrectly?