Programmable controllers ___ contain a battery backup.

Programmable controllers ___ contain a battery backup.

• A. do
• B. do not
• C. sometimes
• D. never

Answer: (A)

Programmable controllers typically keep the program and data in RAM, which loses its contents when power is removed. A battery backup provides power to that memory for a short time during outages, so the controller can retain critical information, preserve the real-time clock, and avoid losing the program or causing unintended changes. This backup allows a quicker, safer restart after power returns. Some newer controllers use non-volatile memory and may not need a battery backup, but in many designs a battery-backed RAM is standard, so the statement that programmable controllers contain a battery backup is correct.

Programmable controllers typically keep the program and data in RAM, which loses its contents when power is removed. A battery backup provides power to that memory for a short time during outages, so the controller can retain critical information, preserve the real-time clock, and avoid losing the program or causing unintended changes. This backup allows a quicker, safer restart after power returns. Some newer controllers use non-volatile memory and may not need a battery backup, but in many designs a battery-backed RAM is standard, so the statement that programmable controllers contain a battery backup is correct.