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Instruction Leaflet IL158011EN

Effective February 2022

Instructions for replacing ACX controller 

with CX Plus controller (AutoVAR 600)

Overview

Replacing an ACX controller with the communicating  

CX Plus controller involves the following steps:

1. 

Remove the ACX controller and physically install  

the CX Plus controller.

2. 

Install the provided DIN rail mounted terminal  

block beside the location of the existing controller.

3. 

The new controller is prewired. Connect the  

wiring from the old controller to the terminal  

block provided.

4. 

Add the Modbus

T

 wiring terminal block beside the TB1.

5. 

The new controller is preprogrammed. Field verify and 

adjust as needed.

Existing controller removal

1. 

If the capacitor bank is energized, turn the controller  

into Manual Mode and switch off all stages one by one.

2. 

Turn the capacitor bank off by means of the  

ON/OFF switch.

3. 

Ensure the upstream feeder breaker feeding to the 

capacitor bank is turned OFF. Lock it out.

4. 

Follow all facility lock-out/tag-out procedures. Follow  

all safety warnings and signs.

5. 

Ensure no indicating lights are lit on the capacitor bank.

6. 

Wait 5 minutes before opening the door of the capacitor 

bank cabinet.

7. 

Wear appropriate PPE suitable for the arc flash approach 

boundary. Verify there is no voltage on the capacitor  

bank bus.

8. 

Locate terminal block TB1 terminals 1 and 2 on the control 

panel. The field wiring is from a current transformer (CT) 

located at the main service entrance. Use the provided 

shorting jumper and short these two terminals. 

 

Figure 1. Terminal  block TB1

9. 

Mount the provided DIN rail mountable terminal strip on 

the right side of the controller with the provided hardware.  

The DIN rail should be located toward the hinged end of 

the enclosure away from the door latch.

10. 

Label each wire at the back end of the existing controller. 

Labels should identify the name of the terminal on which 

they were connected. Once labeled, loosen the set 

screws and disconnect all wires. 

11. 

Terminate all wires 1 through 14 from the old controller  

on to the new installed terminal strip labeled 1 through 14. 

ote: 

N

 The new controller will only have wires 1 through 12. 

Match the wires 1 through 14 onto the terminals 1 through 14. 

The other end of the terminal strip is already prewired to  

the controller.

12. 

The controller is held in place by two tabs—one on the  

top and one on the bottom of the controller. Slide the tabs 

to slide the controller out of its cutout opening. 

New controller installation

1. 

Position the new controller in place of the old controller. 

2. 

Use the mounting tabs to secure the new controller in 

place by simply pushing the tabs forward and verify the 

controller is properly mounted. 

3. 

Pull the tabs back to release the controller if necessary. 

4. 

If the controller is loosely fitted, then add a gradual 

amount of sealant. 

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