Actuator Limit Switches

Thread Starter


Joined Nov 24, 2020
I am having some issues getting correct wiring for limit switches on a positioner valve.

Perhaps if i explain in reference to the below diagram.

100L+ is a common cable (24VDC+) which is connected the COM on other limit switches (mechanical style). And is meant as the common for these limit switches.

We have OUT connected which at the moment makes the contact between V+ and OUT when the limit switch is made.

The V- is connected to our cable M – this is a 24DVC- cable which is common elsewhere in the panel.

Basically we have connected a 24VDC+ to the V+ and a 24VDC- to V-, when the limit switch is activated/in positiion we want power at OUT (or wherever we need to connect this) onto cables 107/108 which then energies a relay depending on the high or low limit.

The above does not work and both limit switch lamps are permanetly made which is incorrect.

Below is the manufactuer wiring details:

Limit photo.JPG
Any help would be appreciated.


Joined Dec 24, 2019
I am assuming you mean an indicator light built into the limit switches. If so and you disconnect the output wires do the limit switch lights still always stay on? If so it is surely a problem with the switch and not in the connections. Assuming V+ and V- are indeed measured at 24V, and no output connected, the manner in which it is connected is ruled out. At that point it is likely a matter of switch setup, ie. high and low setpoints and LS action.


Joined Jan 23, 2018
I see nothing connected to the limit switches as a load. In addition, there is a limit switch action selector on the panel, is it in the correct position, and finally, are you sure that the switch is actually being activated by whatever it is intended to be sensing?