I WANT TO POST THIS IN BOLD TYPE. IF YOU HAVE PLC's THAT CONTROL YOUR EQUIPMENT, YOU NEED TO MAKE SURE THAT YOU CHANGE THE BATTERY AT LEAST EVERY TWO YEARS AND HAVE A BACKUP PROGRAM. Empirical Maintenance Solutions had to go into a clients facility and re-create the program that controlled his process because his battery was dead. The battery in a PLC is what maintains the program when main power is lost. The client did not have a backup program. The cost to re-create this program was $12,000 because a $80 battery was not changed.