We currently have a potentiometer that is connected to Allen Bradley 22a-d2p3n104 to regulate speed of a motor (A).

I would like to keep that connection but also need to connect the potentiometer to a PLC which controls an air solenoid that will open or close depending on the speed of motor (A).

That is, if the speed is at 100% then open the solenoid every 3 minutes, at 50% open every 2 minutes, and at 0 don't open the solenoid and so on.

How do I connect the pot? It only has three wires. Do I splice the output and connect one wire to the PLC and one to Allen Bradley VFD?

  • \$\begingroup\$ You can have one master speed control input but multiple motors need separate drivers and tach feedback sensors \$\endgroup\$ Mar 16, 2022 at 3:31
  • \$\begingroup\$ I updated the question to better get an idea of what we are trying to do. We have a Click PLC and need to open an Air Solenoid depending on the speed of the motor (a) \$\endgroup\$
    – Mohamed
    Mar 16, 2022 at 3:40
  • \$\begingroup\$ Thresholds need tolerances but also 2 independent ESC motor controllers \$\endgroup\$ Mar 16, 2022 at 3:43
  • \$\begingroup\$ That isn't enough detail. What about all the other %'s in between. No this won't work, without PLC and AB specs \$\endgroup\$ Mar 16, 2022 at 4:30
  • \$\begingroup\$ Bring the analog signal (potentiometer) into the PLC on an Analog Input, then output via Analog Output the speed to the motor, and via Digital Output to the solenoid? \$\endgroup\$
    – Tyler
    Mar 16, 2022 at 13:58

1 Answer 1


The easiest solution would be to get a ganged potentiometer, this gives you two completely isolated but mechanical connected potentiometers. You can also match the resistance to the PLC and ESC.


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