Functions And Operation Examples - Mitsubishi Electric MELSEC-Q Structured Programming Manual

FXCPU Structured Programming Manual
[Device & Common]
2.4.2

Functions and operation examples

1. General type
M8002
Start
X000
Lower limit
X001
Clamping
X002
Upper limit
X003
State relays have many normally-open contacts and normally-closed
contacts in the same way as auxiliary relays, and these contacts can
be used arbitrarily in sequence programs.
When state relays (S) are not used for step ladder instructions, they
can be used in general sequences in the same way as auxiliary relays
(M) (as shown in the right figure).
46
SET
EN ENO
d
S2
STL
EN ENO
s
S2
SET
EN ENO
d
S20
STL
EN ENO
s
S20
Moving down
Y000
SET
EN ENO
d
S21
STL
EN ENO
s
S21
Clamping
Y001
SET
EN ENO
d
S22
STL
EN ENO
s
S22
Moving up
Y002
SET
EN ENO
d
In the stepping type process control shown in the
left figure, when the start signal X000 turns ON,
the state relay S20 is set (turned ON) and the
solenoid valve Y000 for moving down is
activated.
When the lower limit switch X001 turns ON, the
state relay S21 is set (turned ON) and the
solenoid valve Y001 for clamping is activated.
S2 process
When the clamp confirmation limit switch X002
turns ON, the state relay S22 is set (turned ON).
When the operation proceeds to the next step,
the state relay in the preceding step is
automatically reset (turned OFF).
When the PLC is turned OFF, all of general type
state relays are turned OFF.
When the ON/OFF status just before power
S20 process
interruption is required for restart, use latched
(backed-up) type state relays.
S21 process
S22 process
2 Devices in Detail
2.4 State Relay [S]
X001
S10
S10
M30
Y005