GFK-0356Q Chapter 6 Memory Backup/Battery Backup 6-7
6
Configuring a Battery-Less System
Here are the basic steps to configure a system to run battery-less. When configured this way, the
contents of PROM memory will be written into RAM memory each time the PLC powers up.
Ŷ Equip your CPU with a PROM device. On some CPUs a PROM device is purchased as an
option; on others, it is a standard feature. For a table that identifies the standard PROM
configuration for each CPU, see “CPU Firmware and PROM Configurations” in chapter 5.
Ŷ There are three CPU configuration parameters involved. Configure them as follows: Pwr Up
Mode: RUN; Logic/Cfg: PROM; Registers: PROM.
Ŷ Store your folder (include Program Logic, Configuration, and Register Data) to the PLC. This
places your entire folder into RAM (working) memory.
Ŷ Write PLC (RAM) memory to the PROM device. Make sure you write all data (Program
Logic, Configuration, and Register Data) to the PROM. Note that the type of PROM device
depends on what model CPU you have and how it is equipped.
Ŷ If you are using a 340 or higher CPU (such as a CPU350, CPU351, etc.), read the next section
for an additional requirement.
Operation Without a Memory Backup Battery Using a 340 or Higher CPU
This information is applicable only to CPU model numbers 340 and higher (such as CPU350,
CPU351, etc.). In systems that do not use a memory backup battery, a standard 0.1” Berg jumper
should be installed across either of the two power supply battery connectors to ensure reliable
restarting of the CPU after a power cycle. This jumper should not be installed if a battery is
plugged into either the power supply or CPU battery connector.
Determining Battery Age Using Battery Date Code
Battery age can be determined from the date code stamped on the battery.
The battery, manufactured by Panasonic, will have a four-digit date code. It will be something like
5615 or 7Y34. Use the following information to determine the date of manufacture.
Ŷ First digit shows the year in a rotating 10-year cycle. For example, 0=1990, 1=1991, 2=1992
... 9=1999, 0=2000, 1=2001, 2=2002, etc. This seeming duplication should not be a problem
because the shelf life of these batteries is 5 years. Batteries in inventory that are older than 4
years old should be discarded according to the manufacturer’s instructions (since they have
less than one year of life remaining we would not recommend using them in a PLC). This will
ensure that outdated batteries are not mistaken for newer batteries.
Ŷ Second digit shows the month. 1=January, 2=February, 3=March, 4=April, 5=May, 6=June,
7=July, 8=August, 9=September, O=October, Y=November, Z=December.
Ŷ Third digit shows the week of the month.
Ŷ Fourth digit shows the day of the week. 1=Monday, 2=Tuesday, 3=Wednesday, 4=Thursday,
5=Friday, 6=Saturday, 7=Sunday.
For example, the code 7612 is interpreted as:
Manufactured on June 3, 1997
To Next Page
Loading...
Need help?
General
