APPENDICES
Appendix 5 Method of replacing High Performance model QCPU with Universal model QCPU
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Appendix 5.4.3 Device Latch Function
(1) Overview
This section explains how to use the latch function *1 of the Universal model QCPU,
which has been enhanced compared with the High Performance model QCPU.
* 1: The latch function is a function that allows device data retention even if power is turned OFF or
the CPU module is reset.
(2) Methods for the latch function
Device data of the Universal model QCPU can be latched by:
• Large-capacity file registers (R, ZR)
• Writing/reading device data to the standard ROM (SP.DEVST/S(P).DEVLD
instructions)
• Specifying internal user devices as latch ranges
(3) Latch function details
(a) Large-capacity file registers (R, ZR)
File registers are the devices whose data can be latched by batteries.
The Universal model QCPU has file registers of larger capacities than the High
Performance model QCPU, offering a high-speed file registers processing. If
many device points are to be set for latching, it is advisable to use the file
registers.
TableApp.78 shows capacities of file registers for each CPU module.
* 1: Use of a memory card can increase the number of points.
(b) Writing/reading device data to the standard ROM (SP.DEVST/S(P).DEVLD
instructions)
Device data of the Universal model QCPU can be latched using the instructions
for writing/reading them to/from the standard ROM (SP.DEVST/S (P).DEVLD).
Utilizing the standard ROM allows data backup without batteries. This method is
effective for latching data that will be updated less frequently.
TableApp.78 Capacities of file registers for each CPU module
Model
Q02UCPU
Q03UDCPU,
Q03UDECPU
Q04UDHCPU,
Q04UDEHCPU
Q06UDHCPU,
Q06UDEHCPU
Q13UDHCPU,
Q13UDEHCPU
Q26UDHCPU,
Q26UDEHCPU
Capacity of file register (R, ZR)
in standard RAM
*1
64k points
96k points
128k points
384k points
512k points
640k points
