Application:-In electrical panel, operate green lamp
with NO contact of relay and operate red lamp with NC contact of relay. Write
PLC program using ladder diagram language.
Diagram:-Basic operation Machine ON lamp and OFF
lamp electrical wiring diagram in the panel.
As shown in figure consider two lamps, red lamp is for
machine OFF and green lamp is for machine ON. Once relay will get 24v dc
machine ON signal, relay will be ON and green lamp will be ON. We have taken
here NO contact for green lamp so supply will pass from C to NO as show in
figure and if relay is OFF, supply will pass from C to NC so red lamp will
be ON.
Components:-24V dc red lamp, 24V dc green lamp, 24V
dc relay, wires, 24V dc source, Programmable Logic Controller
PLC program:-
We can write this logic in PLC also. We can use any PLC
for this logic. For logic purpose consider Memory coils and outputs.
M coil:-
M0.0 (NO) =Green lamp ON
M0.0 (NC) =Red lamp ON
Outputs:-
Q0.0=Machine command
Q0.1=Green Lamp
Q0.2=Red lamp
PLC program:-
We can write this logic in PLC also. We can use any PLC
for this logic. For logic purpose consider Memory coils and outputs.
PLC program explanation:-
In network 1
we have taken NO contact of machine command (Q0.0) so when machine command is
ON, green lamp (Q0.1) will be ON.
In network 2
we have taken NC contact of machine command (Q0.0) so when machine is off, red
lamp (Q0.2) will be ON.