What is a PLC battery?
A PLC battery is an important part of the Programmable Logic Controllers (PLCs) that is used to store data in the controller’s RAM when power is lost or when the PLC is disconnected for service or moved to another location. This memory stores configuration settings, process set points, logic programs, and real-time clock data. In the absence of the battery, this information is erased and would require reprogramming if the system fails to operate.
Lithium Thionyl chloride battery is the common type of battery used in PLC that has long life span and is suitable for low current usage. Such batteries normally have an output voltage of 3V or 3.6V, but higher voltage is possible by joining the cells in series. Lithium batteries can last up to 5 years, while capacitor-based assemblies can provide backup for shorter time of 72 hours.
It is important that the batteries of PLCs are well managed and maintained. They should never be charged, punctured, ignited or short-circuited. It helps in ensuring that the voltage is kept within the recommended ranges in order to prevent data loss. The PLC battery is very useful in ensuring that programmed logic and system configurations are protected, and the system is able to run efficiently in the event of power failure.