Slave Status Area Mapping; Data Exchange Method - Omron C200HW-PRM21 Operation Manuals

Unit Settings

5-1-2 Slave Status Area Mapping

5-1-3 Data Exchange Method

DM m+14 and DM m+15 define the PLC data area where the 16 words of
slave status information are to be mapped. By default (i.e. both settings are 0)
the Unit uses IR200 ~ IR215, an IR area originally reserved for SYSMAC BUS
slaves. Therefore, if the Unit is used in combination with a SYSMAC BUS
remote master unit, the default mode should not be used.
DM word Value
m+14 Slave status data mapping mode
0001
other
m+15 Start address in user-defined mapping mode
(Area size = 16 words)
0000 ~ 4080
0000 ~ 5984
A000 ~ A220
A300 ~ A496
B000 ~ B084
C000 ~ C048
other
The user is to verify that the assigned area is not yet allocated to other Units.
DM m+16 defines the data exchange procedure between the Unit and the
PLC. The two possible exchange methods are:
1. Asynchronous: the fieldbus cycles are triggered independently of the PLC
cycle and therefore the fieldbus cycles run asynchronous with the PLC
cycle. This method provides optimal I/O response time when the PLC
cycle time is at least twice the fieldbus cycle time.
2. Synchronous: The fieldbus cycles are triggered at the end of an I/O refresh
and therefore the fieldbus cycle is synchronised with the PLC cycle. If the
fieldbus cycle time is greater than the PLC program execution time, the
next fieldbus cycle will not be triggered until the completion of the next I/O
refresh. This method ensures synchronisation between PLC cycle and
fieldbus cycle.
These exchange methods are described in more detail in section 3-2.
DM word Value
m+16 Data exchange procedure
0000
other
Note In synchronous mode, with the slave watchdog enabled (configurable), the
PLC cycle time should be less than the set watchdog time (configurable)
otherwise the watchdog of the slave will expire. If the PLC cycle time can not
be reduced, the watchdog time of the slave must be set to a larger value, or
the asynchronous mode must be used.
Meaning
User defined mapping defined by DM m+15
Default mapping to IR200 ~ IR215
DM0000 ~ DM4080 (C200HE-CPU11)
DM0000 ~ DM5984 (all other CPUs)
IR000 ~ IR220
IR300 ~ IR496
HR00 ~ HR84
LR00 ~ LR48
Default mapping to IR200 ~ IR215
Meaning
Default, fieldbus cycle asynchronous with PLC cycle
Fieldbus cycle synchronous with PLC cycle
Section 5-1
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