App - 53
APPENDICES
(3) System clocks/counters
Table App. 2.4. Special relay
Number Name Meaning Explanation
Set by
(When Set)
Corres-
ponding
ACPU
M9
Corresponding
CPU
SM400 Always ON • Normally is ON
S (Every END
processing)
M9036 QnA
SM401 Always OFF • Normally is OFF
S (Every END
processing)
M9037
QnA
SM402
After RUN, ON for 1
scan only
• After RUN, ON for 1 scan only.
• This connection can be used for scan execution type
programs only.
• When an initial execution type program is used, this
relay turns OFF at the END processing of the scan
execution type program in the first scan after RUN.
S (Every END
processing)
M9038 QnA
SM403
After RUN, OFF for 1
scan only
• After RUN, OFF for 1 scan only.
• This connection can be used for scan execution type
programs only.
• When an initial execution type program is used, this
relay turns OFF at the END processing of the scan
execution type program in the first scan after RUN.
S (Every END
processing)
M9039 QnA
SM404
Low speed execution
type programON for 1
scan only after RUN
• After RUN, ON for 1 scan only.
• This connection can be used for low speed execution
type programs only.
S (Every END
processing)
New QnA
SM405
Low speed execution
type programAfter
RUN, OFF for 1 scan
only
• After RUN, OFF for 1 scan only.
• This connection can be used for low speed execution
type programs only.
S (Every END
processing)
New
QnA
SM410 0.1 second clock
• Repeatedly changes between ON and OFF at each
designated time interval.
• When PLC power supply is turned OFF or a CPU
module reset is performed, goes from OFF to start.
(Note that the ON-OFF status changes when the
designated time has elapsed during the execution of
the program.)
S (Status change)
M9030 QnA
SM411 0.2 second clock M9031
QnA
SM412 1 second clock M9032
QnA
SM413 2 second clock M9033
QnA
SM414 2n second clock
• This relay alternates between ON and OFF at
intervals of the time (unit: s) specified in SD414.
• When PLC power supply is turned OFF or a CPU
module reset is performed, goes from OFF to start.
(Note that the ON-OFF status changes when the
designated time has elapsed during the execution of
the program.)
S (Status change)
M9034form
at change
QnA
SM420 User timing clock No.0
• Relay repeats ON/OFF switching at fixed scan
intervals.
• When PLC power supply is turned ON or a CPU
module reset is performed, goes from OFF to start.
• The ON/OFF intervals are set with the DUTY
instruction
n1: ON scan interval
n2: OFF scan interval
S (Every END
processing)
M9020
QnA
SM421 User timing clock No.1 M9021
SM422 User timing clock No.2 M9022
SM423 User timing clock No.3 M9023
SM424 User timing clock No.4 M9024
SM430 User timing clock No.5
• For use with SM420 to SM424 low speed programs
S (Every END
processing)
New QnA
SM431 User timing clock No.6
SM432 User timing clock No.7
SM433 User timing clock No.8
SM434 User timing clock No.9
ON
OFF
ON
OFF
ON
OFF
1 scan
ON
OFF
1 scan of scan
execution type
program
Initial
execution
type program
ON
OFF
1 scan
ON
OFF
1 scan of scan
execution type
program
Initial
execution
type program
ON
OFF
1 scan
ON
OFF
1 scan
0.05s
0.05s
0.1s
0.1s
0.5s
0.5s
1s
1s
ns
ns
n1 scan
n2 scan n2 scan
DUTY n1 n2 SM420