Omron SYSMAC C Series User Manual

Application examples
Ladder diagram
0000
0500
0002
)
0001
DIFD 1000
1000
0501
0003
Coding chart
Instruction
In response to the input signals sent from these switches, the C20 issues
control outputs that drive the motor of the door for opening and closing.
The C20 also receives inputs from two additional switches: one detects
the upper limit of the door movement and the other detects the lower limit.
The following is part of a ladder diagram that might be used to perform
these coordinated tasks.
1/0 assignment
Ultrasonic switch
Photoelectric switch
Switch detecting upper limit of door movement
Switch detecting lower limit of door movement
Output
To raise door
To lower door
Operation
As we see in the ladder diagram, the input signal from the ultrasonic
switch (input 0000) is ANDed with a limit switch (input 0002) that detects
the upper limit of the door movement. This switch is normally closed.
When input 0000 turns on, the C20 outputs a signal (output 0500) that
starts the motor to open the door. When the door moves to its upper limit,
input 0002 turns on. This stops the output 0500 signal, and that stops the
motor.
At the same time, the input signal from the photoelectric switch (input
0001) is connected to a differentiation-down circuit. (This circuit is
programmed by the DIFD instruction, described in Appendix B, Instruc-
tion words.) This connection causes Interna! Auxiliary Relay 1000
assigned to the DIFD instruction to turn on for only one program scan time
at the falling edge of input 0001. Internal Auxiliary Relay 1000 is ANDed
with a second limit switch that detects the lower limit of the door
movement. Consequently, when Internal Auxiliary Relay 1000 turns on the
AND condition is satisfied for one scan time. During this period, output
501 turns on. This then turns on the motor which lowers the door.

Omron SYSMAC C Series Specifications

General

Brand	Omron
Model	SYSMAC C Series
Category	Controller
Language	English