Appendix 3.4.3 Device Latch Function - Mitsubishi Electric melsec q00ujcpu User Manual

Appendix 3.4.3
Device latch function
(1) Overview
The device latch function
model QCPU and High performance model QCPU.
This section describes the enhanced device latch function in the Universal model QCPU.
*1: The latch function is used to hold device data even when the CPU module is powered off or reset.
(2) Device data latch methods
Device data of the Universal model QCPU can be latched by:
• using the large-capacity file register (R, ZR),
• writing/reading device data to the standard ROM (with the SP.DEVST and S(P).DEVLD instructions), or
• specifying a latch range of internal user devices.
(3) Details of each latch method
(a) Large-capacity file register (R, ZR)
Data in the file register can be latched by batteries.
File register size is larger and processing speed is higher in the Universal model QCPU, compared to the Basic
model QCPU and High Performance model QCPU.
To latch a lot of data (many device points), use of the file register is effective.
TableApp.37 shows the file register size available for each CPU module.
Q00UCPU,Q01UCPU,Q02UCPU
Q03UDCPU,Q03UDECPU
Q04UDHCPU,Q04UDEHCPU
Q06UDHCPU,Q06UDEHCPU
Q10UDHCPU,Q13UDHCPU,Q10UDEHCPU,Q13UDEHCPU
Q20UDHCPU,Q20UDHCPU,Q26UDEHCPU,Q26UDEHCPU
(b) Writing/reading device data to the standard ROM (SP.DEVST and S(P).DEVLD instructions)
Device data of the Universal model QCPU can be latched using the SP.DEVST and S (P).DEVLD instructions
(instructions for writing/reading data to/from the standard ROM).
Utilizing the standard ROM allows data backup without batteries.
This method is effective for latching data that will be updated less frequently.
*1
for the Universal model QCPU is more enhanced compared to that for the Basic
TableApp.39 File register size available for each CPU module
Model File register (R, ZR) size in the standard RAM
64K points
96K points
128K points
384K points
512K points
640K points
APPENDICES
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APPEN-
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