Kohler MPAC 1000 Transfer Switch Controller Modbus Communications Protocol for Automatic Transfer Switches Protocol Operation Manual (tp6208)

This MPAC 1000 Modbus protocol operation manual is what I reach for when a generator and its automatic transfer switch are sitting in a plant room or data center and need to “talk” cleanly to a building management system. It helps you understand exactly how the controller behaves over Modbus so you can start, stop, and monitor the transfer switch without confusing the logic or stressing the equipment. For example, if the BMS is showing bad status bits or not tracking load transfers correctly, I use this document to trace which registers to poll and how to command the switch without causing nuisance transfers.

Applications & Use Cases

• Set up Modbus polling so the BMS or SCADA reads the right MPAC 1000 status and alarm points.
• Verify remote commands are formatted correctly before you let the system initiate transfers automatically.
• Troubleshoot communication faults when the switch isn’t reporting position, source availability, or alarms as expected.
• Align plant documentation by labeling points and tags to match the controller’s Modbus map.
• Test new integrations after controller replacement or software updates to ensure safe, predictable switching.

FAQ

Q: Can I keep this manual on a tablet in the switch room?

A: Yes, a digital copy works well; you can zoom in on maps and search for specific points while you test communications.

Q: Is it worth printing parts of this manual?

A: I usually print the key Modbus mapping pages and keep them in the ATS cabinet for quick reference during commissioning.

Safety Note

Always disable automatic operation and follow lockout/tagout procedures before changing any control or communication settings.

Kohler MPAC 1000 Transfer Switch Controller Modbus Communications Protocol for Automatic Transfer Switches Protocol Index:

Safety Precautions and Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Modbus Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Related Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Service Assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
Section 1 Controller Connection and Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3 Hardware Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.4 Controller Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4.1 Network Interface Port Display Window . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4.2 Network Interface Port Setup Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Section 2 Modbus Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Modbus Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.3 Modbus Protocol Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.4 Modbus Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.5 Event Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Appendix A Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-17
Appendix B Noise and Wiring Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-20

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