0-10V control logic for motor CW, CCW and OFF

[Wesley Weaver]

I have a 24vdc, dc motor controlled, linear actuator.

I have a constant 24vdc power supply.

I have a controls system that uses a 0-10vdc control signal.

I also know JUST enough about electronics to be dangerous.

I need to figure a way to move the actuator in (motor CW), out(motor CCW), and hold ( motor off) using the varying voltage control signal.

I know I can use a FET H-bridge to control the bidirectional movement, but with only that it will always be moving either in or out (CW or CCW) not off.

I need to build logic that will check for a voltage above 0 (for on versus off) and combine that with a high signal or low signal (to apply the 24vdc to move it CCW or CW).

Is there some sort of IC that will generate a HI with anything above 1volt for instance that I can gate off the power supply to the H-Bridge with a PNP FET?

I'm just sort of lost.

I hope I gave enough info.

 

[KMoffett]

Logic to an H-bridge will allow CW, CCW, and OFF.

Is the intent to have the 0-10V signal drive the position of the actuator?

Does your actuator have an internal potentiometer that feeds back the position? Maybe a link to it's datasheet.

Ken

 

[Wesley Weaver]

(Logic to an H-bridge will allow CW, CCW, and OFF.)

I'm confused how you'd have OFF with the H-Bridge alone... wouldn't a high signal route current one direction and the low (or 0vdc) signal route it the other? So no matter what it would be going in or out? What signal would result in off?

I was thinking maybe a transistor/FET that could close contact at >= like 1v to gate the 24vdc supply voltage to the bridge all together, then if the voltage was 1 the bridge would read low and if the voltage was 10 it would read high and open/close appropriately. That way if we had the control signal at 0vdc the supply voltage would never even make it to the bridge?

Does that make sense? Or is there an easier way?


(Is the intent to have the 0-10V signal drive the position of the actuator?)

No just in, out, and off.



(Does your actuator have an internal potentiometer that feeds back the position? Maybe a link to it's datasheet.)

Yes it has an internal pot feedback but that gets read directly by the controls system and we use software programming to figure position from the resistance, no questions there.


Ohh and we don't have a good data sheet for the actuator :/ Frustrating... it seems to be unavailable.

 

[KMoffett]

An integrated H-bridge has two inputs. There are four possible states. Go down to "H-bridge with 2 Relays": http://www.talkingelectronics.com/projects/H-Bridge/H-Bridge-1.html for the concept.
This can be solid state as well as electromechanical. The OFF (Brake) has both inputs high or low at the same time.
So is the "never 0V condition" a safety idea?
What is the maximum current draw of the actuator?
Is the controller a PLC?

Ken