270
4.30 Buffer Memory Data Backup Function
This function allows buffer memory data to be stored in E
2
PROM and backed up.
The backed-up data is transferred from E
2
PROM to the buffer memory when the power is turned off and on or the CPU
module is reset and the reset is cancelled. Therefore, temperature can be controlled without writing data when the
power is turned off and on or the CPU module is reset and the reset is cancelled.
(1) Applicable buffer memory areas
Refer to the buffer memory assignment list.
Page 59, Section 3.4.1
(2) Data write to E
2
PROM
This function can be used to back up data directly written in the buffer memory using the PID constants set with
the auto tuning function and the programming tool. When data is written to E
2
PROM and the power is turned off
and on or the CPU module is reset and the reset is cancelled, the buffer memory setting value is not required to
be set again.
For the function that allows PID constants to be automatically backed up after auto tuning, refer to Page 178, Section
4.6 (4).
To write data to E
2
PROM, turn off and on E
2
PROM backup instruction (Yn8).
When data write to E
2
PROM is completed, E
2
PROM write completion flag (Xn8) turns on.
If data write to E
2
PROM does not complete, E
2
PROM write failure flag (XnA) turns on.
(a) Setting change
Change the settings for buffer memory areas when E
2
PROM write completion flag (Xn8) is off.
Common
Read
Q64TCN
OS
CPU module
1. E
2
PROM backup
instruction (Yn8): ON
(Write instruction)
3. E
2
PROM write
completion flag (Xn8):
ON (completed)
Buffer memory
data
2. Write
E
2
PROM
When the power is
switched from off to
on or at reset