DVP-ES2-EX2-SS2-SA2-SX2-Operation Manual

2. Programming Concepts
2.16 Applications of Special M Relays and D Registers
Function Group
Number
PLC Operation Flag
M1000~M1003
Contents:
These relays provide information of PLC operation in RUN status.
M1000:
NO contact for monitoring PLC status. M1000 remains “ON” when PLC is running.
M1000
Y0 PLC is running
Normally ON contact
in PLC RUN status
Keeps being ON
M1001:
NC contact for monitoring PLC status. M1001 remains “OFF” when PLC is running.
M1002:
Enables single positive pulse for the first scan when PLC RUN is activated. Used to initialize
registers, ouptuts, or counters when RUN is executed..
M1003:
Enables single negative pulse for the first scan when PLC RUN is activated. Used to initialize
registers, ouptuts, or counters when RUN is executed.
PLC RUN
M1000
M1001
M1002
M1003
scan time
Function Group
Number
Monitor Timer
D1000
Contents:
1. Monitor timer is used for moitoring PLC scan time. When the scan time exceeds the set value
(SV) in the monitor timer, the red ERROR LED will be ON and all outputs will be “OFF”.
2-55