FX2N outputs.

Hi.

Im straight out of uni where i touched on automation and control. I am finding the world outside my pre-wired plc training systems to be much more involved.
Can someone tell me why i cannot see any output voltage from an actuated relay output on my FX2N plc when i try to measure with a multimeter?
From the manual i gather that the power to the outputs are being supplied by the plc->item 6 being power supply for loads.

Thanks in advance.

For relay outputs you will see there are two connections, i.e Y0 and Y0, further along you will see something like COM, Y5,Y6.

Where there are two connections you must put the supply in and you will get a supply out if the output is on, with the COM put the supply to the COM which is common to the two or four outputs

you can of course switch negative if you wish, watch the ratings of the contacts for both voltage and current.


Chris

Thanks for the quick reply Chris...

Ah i see. So im creating a complete circuit including dc supply, and when the relay is set it closes the circuit.
My model doesnt have a COM terminal, just yo to y7.

I feel dumb for trying to measure the voltage at the output.

digi said:

My model doesnt have a COM terminal.....

Click to expand...

It will have a common terminal somewhere, it can't work without it...

Read the manual.....

When a PLC has what is called an isolated output it may or may not be labeled with a COM and Y0 terminal. The two terminals associated with that output may be labeled Y0 and Y0 just as your pictures show.
Here is the procedure if you simply want to see if the relay output is functional. With no wires connected to either of the Y0 terminals, connect the red lead of the multitester to one Y0 terminal. With no wires connected to either of the Y0 terminals, connect the black lead of the multitester to the other Y0 terminal. Switch the multitester to read ohms or continuity. Activate the output to the "ON" state with your PLC program. At this point you should read a low value of resistance. When you De-activate the output you should read a very high resistance value or infinity.

Thanks for the explanations, i have a much better understanding now.

Using this, i am trying the control of a linear actuator. I have written a simple program that sets y1 for 5 seconds (retracting) after y0 has been set for 5 seconds (extending).
Can i get a hint as to how to wire this using one power supply? I cant think of a way that doesnt short out the actuator during the retract.
Thanks.

digi said:

Thanks for the explanations, i have a much better understanding now.

Using this, i am trying the control of a linear actuator. I have written a simple program that sets y1 for 5 seconds (retracting) after y0 has been set for 5 seconds (extending).
Can i get a hint as to how to wire this using one power supply? I cant think of a way that doesnt short out the actuator during the retract.
Thanks.

Click to expand...

Eh, really ?

Turn on Y1 for 5 seconds, turn off Y1, turn on Y0 for 5 seconds, what are you going to short doing that ?

I perform the extend by sending current into the positive terminal of the actuator and out the neg, and i perform the retract by doing the opposite.
I'm not sure how to wire it to my plc outputs that doesnt go around the actuator straight back to the power supply when y0 is open and y1 closed.

Know it must be frustrating for you dealing with such a noob but thanks for your help..

digi said:

.
Can i get a hint as to how to wire this using one power supply? I cant think of a way that doesnt short out the actuator during the retract.
Thanks.

Click to expand...

I believe what you want is called an "H" bridge
http://en.wikipedia.org/wiki/H_bridge

Thanks Milldrone!