Constant Scan Mode [M8039 And D8039] (Fixed Scan Time); State Control In Program By Stl Instruction [M8040] - Mitsubishi Electric MELSEC-Q Structured Programming Manual

FXCPU Structured Programming Manual
[Device & Common]
4. RUN/STOP command from a programming tool
1) When using the programming software for personal computer
The programming software has the remote RUN/STOP function for the PLC.
Use the programming software to set the PLC to the RUN or STOP mode using a command sent from the
personal computer.
2) When using any other programming tool
The PLC enters the RUN mode when M8035 (forced RUN mode) and M8036 (forced RUN input) are set
to ON by the forced ON/OFF operation.
Set M8037 (forced STOP input) to ON in this status to let the PLC enter the STOP mode.
3) When the RUN/STOP switch built in the PLC is set to "RUN"
The remote STOP input from a programming tool and M8037 (forced STOP input) are enabled.

4.2.16 Constant scan mode [M8039 and D8039] (Fixed scan time)

When the special auxiliary relay M8039 is set to ON and desired scan time (in units of ms) is written to the
special data register D8039, the scan time in the PLC does not become shorter than the value stored in
D8039.
If the operation is finished earlier, the PLC pauses for the remaining time, and then returns to the step No. 0.
1. Program example
M8000
RUN monitor
2. Cautions
1) When using an instruction which is executed in synchronization with a scan
a) When using the RAMP, HKY, SEGL, ARWS or PR instruction
It is recommended to use the constant scan mode or turn ON the scan with a constant time interval
using timer interrupts.
b) When using the HKY instruction
It is necessary to set the scan time to 20 ms or more because of the response relay caused by the key
input filter.
2) Scan time display (D8010 to D8012)
In FX /FX
1S 1N
included in the scan time display stored in D8010 to D8012.
In FX /FX /FX
0S 0
in D8010 to D8012.

4.2.17 State control in program by STL instruction [M8040]

When M8040 is set to ON, the state relay ON status is not transferred even if the transfer condition is
satisfied.
Outputs in the stopped state relay continue operation.
→ For resetting outputs in state relays, refer to the FX Structured Programming Manual [Basic &
4.2 Supplement of Special Devices (M8000 and later and D8000 and later)
M8039 Constant scan mode
MOVP
EN ENO
s d
K20 D8039
/FX /FX /FX /FX /FX
1NC 2N 2NC 3S
/FX /FX PLCs, the constant scan time is not included in the scan time display stored
0N U 2C
4 Operations of Special Devices (M8000 and later, D8000 and later)
The constant scan time
is set to "20 ms".
/FX /FX /FX PLCs, the constant scan time is
3G 3GC 3U 3UC
Applied Instruction].
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