Power Supply

Introduction to the ControlLogix Power Supply

This power supply unit supplies power to the modules in the chassis.   It does not normally power field devices, such as lights, solenoids, and motor starters.   The power for field devices will typically come from an external source (with some exceptions).    There is a switch on the unit to turn on or off the output.   Be aware, though, that simply shutting off this switch doesn’t mean it’s safe to change the wiring on on the I/O modules.   Always remember they are powered by an external source.Power Supply


These modules can be purchased which are supplied with a typical 24 volts, or 120/240 VAC.    If you use the 120/240 model, be sure the voltage jumper on the back of the power supply is in the proper position for high or low voltage.

Next, look at the the ratings for the unit.  The ratings can be found inside the door.  You can use RSArchitect to calculate the load on your chassis, or you can calculate this manually.  Each module will usually have a sticker that states the current consumption of each voltage tap.    The current draw of the chassis should not exceed the module’s rating.   If the unit shuts down, you will need to shut off power for 15 or 45 seconds, depending on the model of your power supply, then clear the overload condition.  The label on the module will explain how to reset the power supply if it becomes overloaded.


To replace the unit, shu off the power, and remove the supply lines that are coming into the power supply.   Next, locate the two screws on the right side of the module.    Loosen these two screws, and the power supply will pull straight out toward you.    On the left side of the power supply, you will find the model number.   Finally, check the voltage jumper for the proper voltage (if applicable), and place the new module into your chassis.   Connect the wiring, and turn on power to the supply lines.  Be sure the power supply switch is in the up (on) position, and the chassis should then be powered up.

Please check out other ControlLogix posts on the ControlLogix category page!

— Ricky Bryce

Leave a comment

Your email address will not be published. Required fields are marked *

two + six =