Simple hydraulic positioning

Hello,

A question that does not involve a PLC but I hope someone can help me anyway.

We are to develop a system with a simple hydraulic positioning of a cylinder. The accuracy is not critical.
I have a linear sensor that gives 4-20mA and a proportional valve with on board electronics that uses a +/-10V signal. The setpoint is a 4-20mA or 0-10V signal from an external system. I need no fancy positioning controller. Only a simple PID controller. But I have not found any standard controller that provides a +/10V output signal. Does anyone have any suggestion. The customer will sell this in systems going all over the world and want some of the "big" automation suppliers.

Thanks in advance.

Karsten

Karsten,


Check with Peter Nachtwey (a member here) http://www.deltacompsys.com/products/index.php

Thank you genious,

The Delta products are state of the art motion controllers. I am looking for something simple(cheap). The required accuracy is only +/- 2mm at a 100mm stroke.

The PID needs to be configured for bipolar operation. I use Bosch proportional valves with bipolar PIDs with excellent results.

If you are using an AB PLC search AB.com knowledgebase with the keyword "bipolar" for technotes on how to do it.

We have a much simpler motion controller that we would only sell to high volume OEM applications. It would meet your description except it does have a 4x20 LCD display for setting up limits, scaling and gains. No PC is required for setup unless one needs to change out the firmware. So far we have sold none because no one is willing to commit to 500+ units a year. This would have to be a OEM supported device after initial training.

So far we have found the really serious customer prefer having the support and diagnostics because they can save many times the cost of the controller.

PM me if your customer is really serious.

Peter Nachtwey
President
Delta Computer Systems, Inc.

+/-

I has the same problem about +/- outputs.

Final decision was to use mofset power switches and use stardard transistor outputs.

Just make them double, separate by diods, and you have.

If you need I can send additional information.

Hi Karsten

How about using any of the standard controllers or Smart Relays with a 0-10v output and then put that through a signal converter http://controlsignalconverter.com/ or http://www.axiomatic.com/signal-converter.html
or many others. I think that would allow you to use standard parts from "big automation suppliers" that can be obtained worldwide. The smart relays generally give 1024 steps on their analogue inputs and outputs so check that will give the accuracy you need.

Regards

Bryan

Hello,


Thank you for all good suggestions.

But does no one know of a standalone PID controller that has a +/-10V output?

I still think this is your best option.

http://www.deltacompsys.com/products/motion/rmc70/index.php

You don't have to use all the bells and whistles. You can use just what you need even though it may be over kill for now. The RMC75 can be used as a stand alone controller or just a reference follower.