What is a PLC Battery?

What is a PLC?

Programmable Logic Controllers or PLC’s are digital computers designed to control the automation of electromechanical processes, such as automated assembly line machinery, packaging equipment, lighting systems and material handling systems. The PLC was invented for the American automotive industry, to allow for software revision to make the changes to production when models changed.

Before PLC’s a production change required re-wiring banks of hard wired relays and switches. The programs to control the machinery or manufacturing processes are usually stored in battery-backed-up or non-volatile memory.

Common Types of PLC Batteries

The most common type of PLC battery used for PLC back-up are Lithium-Thionyl Chloride batteries. Lithium-Thionyl Chloride batteries are ideal for low current applications where long PLC battery life is desired. The 2 most common voltages for these batteries are 3 volt and 3.6 volt variants, though higher voltages can be achieved through attaching multiple batteries in series.

PLC Battery Purpose

The purpose of these PLC back-up batteries in PLC’s is to provide the power necessary to retain the contents of non-volatile memory if power is removed from the PLC. These PLC batteries should be maintained regularly to make sure that in the event of power outage or the machine being disconnected from a power source , for moving or maintenance , that the programmed software logic is not lost.

Handling PLC Batteries

There are some precautions to be observed when handling lithium PLC Batteries:

• Do not attempt to charge Lithium PLC Batteries. Overheating and explosion may occur.
• Do not puncture or crush PLC Batteries. The battery could explode or leak toxic, corrosive chemicals.
• Do not incinerate PLC Batteries or expose to high temperatures.
• Do not solder directly to PLC Batteries.
• Do not ship PLC Batteries while connected to equipment.
• Do not short the positive and negative terminals together on a PLC Battery.