
10.
10 -
5
OTHER FUNCTIONS
10.3 Latch Function
When the PLC power is turned ON, the CPU module is reset using the RUN/STOP key
switch, or a instantaneous power failure lasting longer than the allowable momentary
power interruption time occurs, the all device values in the QnACPU are cleared, and the
default values are set in the devices (Bit devices: OFF, word devices: 0).
The latch function retains the data in the devices when performing these operations.
The operations in the program are the same whether or not the latch function is used.
(1) Application of the latch function
The latch function can be used when continuing the control to retain data such as
production quantities, numbers of defects, addresses, etc., even if a instantaneous
power failure longer than the allowable time occurs.
(2) Devices that can be latched
(a) The following devices can be latched.
1) Latch relay
2) Link relay
3) Annunciator
4) Edge relay
5) Timer
6) Retentive timer
7) Counter
8) Data register
9) Link register
(b) The latch range is set on the "Device" in the parameter mode of GPP function.
In latch range setting, it is possible to set a range within which the latch clear key
is effective (Latch (1) Start) and a range within which the key is not effective
(Latch (2) Start). For details on device latch ranges for each device, refer to the
QnACPU Programming Manual (Fundamentals).
POINT
Even if a latch designation is set for a device, the device will not be latched if a
local device designation or device initial value designation is made.
POINT
The devices data in the latch range are retained by the battery (A6BAT) installed
in the CPU module.
(1) Even if a sequence program is written to a memory card and ROM operation
is performed, the battery is required for the latch function.
(2) If the battery connector is disconnected from the CPU module connector while
the PLC power is OFF, the devices data in the latch range is lost.
Содержание Q2ACPU
Страница 1: ......
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Страница 221: ...12 12 12 OVERVIEW OF PROCESSING PERFORMED BY THE QnACPU ...
Страница 222: ...12 13 12 OVERVIEW OF PROCESSING PERFORMED BY THE QnACPU ...
Страница 237: ...12 28 12 OVERVIEW OF PROCESSING PERFORMED BY THE QnACPU MEMO ...
Страница 269: ...16 11 16 POWER SUPPLY MODULE 2 Names and description of parts of the A62P A62PEU and A65P module ...
Страница 271: ...16 13 16 POWER SUPPLY MODULE 4 Names and description of parts of the A66P ...
Страница 343: ...21 21 13 MAINTENANCE AND INSPECTION 21 4 2 Replacement of the fuse for an output module ...
Страница 357: ...22 12 22 TROUBLESHOOTING ...
Страница 359: ...22 14 22 TROUBLESHOOTING MEMO ...
Страница 417: ...App 20 APPENDICES 3 Shift instructions Classification Symbol Description n bit shift 1 bit shift 1 word shift ...
Страница 429: ...App 32 APPENDICES Trigonometric function Classification Symbol Description ...
Страница 432: ...App 35 APPENDICES 15 Clock instructions Classification Symbol Description Clock data read write ...
Страница 537: ...App 140 APPENDICES REMARK 1 Message 1 An error code is displayed in 2 Alert 1 3 Alert 2 ...
Страница 538: ...App 141 APPENDICES APPENDIX 6 EXTERNAL DIMENSIONS Appendix 6 1 CPU Module 1 Q3ACPU Q4ACPU modules Unit mm inch ...
Страница 539: ...App 142 APPENDICES 2 Q2ACPU Q2ACPU S1 modules Unit mm inch ...
Страница 541: ...App 144 APPENDICES 2 A66P power supply module Unit mm inch ...
Страница 542: ...App 145 APPENDICES Appendix 6 3 Main Base Unit 1 A32B base unit 2 A32B S1 base unit Unit mm inch Unit mm inch ...
Страница 543: ...App 146 APPENDICES 3 A35B base unit 4 A38B A38HB A38HBEU base unit Unit mm inch Unit mm inch ...
Страница 567: ...MEMO ...
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