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5-7SectionUsing Protocol Macros
90
The following diagram shows an example in which sequence number 000
(PRESENT VALUE READ) of a Temperature Controller (E5jK Read System) is
executed using the PMCR(––) instruction. If the sequence has been completed
normally, the present value that has been read is transferred to another word.
Protocol Macro
Executing Flag
Protocol Macro
Executing Flag
If input condition IR 00000 is ON and the Protocol
Macro Executing Flag IR 20708 is OFF, then sequence
No. 000 is executed for Serial Communications Board
port 1 and the present value is stored in DM 0201 and
after.
If Protocol Macro Executing Flag IR 20708 turns OFF,
IR 00100 turns ON (and remains ON for one cycle).
Protocol Macro
Executing Flag
Step Error
Processing Flag
If Protocol Macro Executing Flag IR 20708 is OFF and
Step Error Processing Flag IR 20709 is OFF when
IR 00100 turns ON, then the data received in DM 0201 is
moved to DM 0300.
If IR 00100 is ON (sequence end) and Step Error Pro-
cessing Flag IR 20709 is ON, the sequence has ended
abnormally and a FAL(06) instruction (FAILURE ALARM
AND RESET instruction) is executed.
Protocol Macro
Executing Flag
IR 20708
Sequence
executed
Sequence
completed
Sequence
re-executed
One cycle
When sequence ended
normally:
Step Error Processing
Flag IR 20709
When sequence ended
abnormally:
Step Error Processing
Flag IR 20709
DIFD (14) 00100
MOV (21)
DM 0201
DM 0300
FAL (06) 01
Input condition
20708
20708
000100
000000
20708 20709
20709
PMCR
#1000
DM 0100
DM 0200
00100
Step Error
Processing Flag
Present value in DM 0201
moved to DM 0300
FAL instruction executed
Input condition
Precaution on Reception Failures for PMCR(––)
The reception buffer is cleared to all zeros just before the communications se-
quence is executed. If programming is included in the ladder diagram to periodi-
cally read, it should be designed to read the data only when receptions are suc-
cessful, and not when the contents of the buffer has been cleared to all zeros.
The above ladder programming shows one way to achieve this.
Ladder Programming
Example