51
CPU Unit Operation
Section 2-4
2-4
CPU Unit Operation
2-4-1
General Flow
The following flowchart shows the overall operation of the CPU Unit. First the
user program is executed and then I/O is refreshed and peripheral servicing is
performed. These processes are then repeated in cyclic fashion.
Startup
initialization
I/O refreshing
(even in
PROGRAM
mode)
Peripheral
servicing
Cycle time
Initialize hardware
memory and system work
area.
Detect I/O.
Automatically transfer data
from Memory Cassette.
Clear I/O memory.
Check user memory.
Clear forced status, etc.
Check the Battery.
Read DIP switch settings.
Check I/O bus.
Check user program
memory.
Overseeing
processing
Program
execution
Operation processing: Execute the user program.
Error processing: Turn OFF outputs. (Reset Units
for bus errors.)
After error: Clear I/O memory if an error occurs
(unless a FALS(007) instruction created the error).
Refresh data for the following Units.
CP-series Expansion Units and Expansion I/O Units
Perform the following servicing if any events have occurred.
Ethernet port servicing
Serial port servicing
Communications port servicing
Built-in flash memory access servicing
Memory Cassette access servicing
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Summary of Contents for CP1L-EL20DR-D
Page 3: ...CP1L EL20D CP1L EM30D CP1L EM40D CP1L EL EM CPU Unit Operation Manual Produced July 2017...
Page 4: ...iv...
Page 10: ...x...
Page 22: ...xxii...
Page 34: ...xxxiv Software Licenses and Copyrights 7...
Page 192: ...158 Trial Operation and Debugging Section 5 3...
Page 250: ...216 Automatic Clock Adjustment and Specifying Servers by Host Name Section 6 7...
Page 666: ...632 Trouble Shooting Section 11 7...
Page 696: ...662 Standard Models Appendix A...
Page 805: ...771 Connections to Serial Communications Option Boards Appendix F Connecting to Unit...
Page 806: ...772 Connections to Serial Communications Option Boards Appendix F...
Page 836: ...802 PLC Setup Appendix G...
Page 838: ...804 TCP Status Transitions Appendix H...
Page 840: ...806 Ethernet Network Parameters Appendix I...
Page 842: ...808 Buffer Configuration CP1L EL EM Appendix J...
Page 844: ...810 Ethernet Specifications Appendix K...
Page 851: ...Index 817 work words 118 write protection 447...
Page 852: ...818 Index...
Page 854: ...820 Revision History...
Page 855: ......