PowerPoint® Presentation

Chapter 9PLC and System Maintenance

Chapter 9PLC and System Maintenance

PLC System Maintenance • PLC Hardware Maintenance • Visual Inspections • Energized PLC

Maintenance • Battery Maintenance • PLC Software Maintenance • Equipment and Documentation

Verification • Software and Program Verification

Chapter 9 — PLC and System Maintenance

The maintenance of a PLC must be carefully documented for future reference.

Chapter 9 — PLC and System Maintenance

PLC maintenance is performed after the application is stopped and a lockout/tagout is applied.

Chapter 9 — PLC and System Maintenance

PLC hardware maintenance is work performed by a technician that consists of a visual inspection of a PLC, energized maintenance procedures, and battery maintenance.

Chapter 9 — PLC and System Maintenance

A visual inspection of a PLC and PLC-related components is part of PLC hardware maintenance.

Chapter 9 — PLC and System Maintenance

Proper personal protective equipment (PPE) must be used when performing energized maintenance on a PLC.

Chapter 9 — PLC and System Maintenance

Backup batteries for the CPU of a PLC can be behind the hinged door or cover of the CPU or mounted on the processor card.

Chapter 9 — PLC and System Maintenance

A PC, an interface cable, and sometimes an interface card are required to connect a PC to a PLC and use the PLC programming software.

Chapter 9 — PLC and System Maintenance

A documented program contains address descriptions, instruction comments, rung comments, and page titles.

Chapter 9 — PLC and System Maintenance

When connecting a PC to a PLC, the technician must be aware of certain technical issues and follow a series of steps.

Chapter 9 — PLC and System Maintenance

PLCs have electrically erasable programmable read-only memory (EEPROM) chips to provide a backup to RAM memory.

Chapter 9 — PLC and System Maintenance

After the machine or process is started, the PLC program must be copied to a separate medium and stored in a safe location.