127
Overview of I/O Memory Area
Section 4-1
4-1-3
Clearing and Holding I/O Memory
Note
1.
Mode changed from PROGRAM to RUN/MONITOR or vice-versa.
2.
The PLC Setup’s
IOM Hold Bit Status at Startup
setting determines wheth-
er the IOM Hold Bit’s status is held or cleared when the PLC is turned ON.
4-1-4
Hot Start/Hot Stop Functions
Operating Mode Changes
Hot Start
Turn ON the IOM Hold Bit to retain all data* in I/O memory when the CPU Unit
is switched from PROGRAM mode to RUN/MONITOR mode to start program
execution.
Hot Stop
When the IOM Hold Bit is ON, all data* in I/O memory will also be retained
when the CPU Unit is switched from RUN or MONITOR mode to PROGRAM
mode to stop program execution.
Note
*The following areas of I/O memory will be cleared during mode changes
(between PROGRAM and RUN/MONITOR) unless the IOM Hold Bit is ON:
the CIO Area (I/O Area, Data Link Area, CPU Bus Unit Area, Special I/O Unit
Area, DeviceNet (CompoBus/D) Area, and Internal I/O Areas), Work Area,
Timer Completion Flags, and Timer PVs.
Area
Mode changed
1
Fatal error generated
PLC power turned ON
Execution of FALS
Other fatal errors
PLC Setup set to
clear IOM Hold Bit
status
2
PLC Setup set to
hold IOM Hold Bit
status
2
IOM Hold
Bit OFF
IOM Hold
Bit ON
IOM Hold
Bit OFF
IOM Hold
Bit ON
IOM Hold
Bit OFF
IOM Hold
Bit ON
IOM Hold
Bit OFF
IOM Hold
Bit ON
IOM Hold
Bit OFF
IOM Hold
Bit ON
CIO
Area
I/O Area
Cleared
Retained
Retained
Retained
Cleared
Retained
Cleared
Cleared
Cleared
Retained
Serial PC Link Area
Internal I/O Area
Work Area (W)
Cleared
Retained
Retained
Retained
Cleared
Retained
Cleared
Cleared
Cleared
Retained
Holding Area (H)
Retained
Retained
Retained
Retained
Retained
Retained
Retained
Retained
Retained
Retained
Auxiliary Area (A)
Status treatment depends on address.
Data Memory Area (D)
Retained
Retained
Retained
Retained
Retained
Retained
Retained
Retained
Retained
Retained
Timer Completion Flags (T)
Cleared
Retained
Retained
Retained
Cleared
Retained
Cleared
Cleared
Cleared
Retained
Timer PVs (T)
Cleared
Retained
Retained
Retained
Cleared
Retained
Cleared
Cleared
Cleared
Retained
Counter Completion Flags (C)
Retained
Retained
Retained
Retained
Retained
Retained
Retained
Retained
Retained
Retained
Counter PVs (C)
Retained
Retained
Retained
Retained
Retained
Retained
Retained
Retained
Retained
Retained
Task Flags (TK)
Cleared
Cleared
Retained
Retained
Cleared
Cleared
Cleared
Cleared
Cleared
Cleared
Index Registers (IR)
Cleared
Retained
Retained
Retained
Cleared
Retained
Cleared
Cleared
Cleared
Retained
Data Registers (DR)
Cleared
Retained
Retained
Retained
Cleared
Retained
Cleared
Cleared
Cleared
Retained
PROGRAM
Retain
I/O memory
CIO and
other areas
MONITOR or RUN
PROGRAM
Retain
MONITOR or RUN
I/O memory
CIO and
other areas
Summary of Contents for CP1L-L14D Series
Page 2: ...CP1L L14D CP1L L20D CP1L M30D CP1L M40D CP1L CPU Unit Operation Manual Revised June 2007...
Page 3: ...iv...
Page 9: ...x...
Page 13: ...xiv TABLE OF CONTENTS...
Page 21: ...xxii...
Page 33: ...xxxiv Conformance to EC Directives 6...
Page 65: ...32 Function Blocks Section 1 5...
Page 153: ...120 CP CPM1A series Expansion I O Unit Wiring Section 3 6...
Page 523: ...490 Troubleshooting Unit Errors Section 9 4...
Page 531: ...498 Replacing User serviceable Parts Section 10 2...
Page 563: ...530 Auxiliary Area Allocations by Function Appendix C...
Page 611: ...578 Auxiliary Area Allocations by Address Appendix D...
Page 638: ...605 Connections to Serial Communications Option Boards Appendix F Connecting to Unit...
Page 639: ...606 Connections to Serial Communications Option Boards Appendix F...
Page 669: ...636 Index...
Page 671: ...638 Revision History...