Proface AGP3500 - 10.4 DIO HMI" - Manual (Page 188)

Chapter 8 Installation and Wiring
8-17
„Interlock Circuit 2
If there is a possibility that the abnormal operation of the GP may lead to an accident, design a fail-safe
measure to configure an interlock circuit with external hardware devices.
For a system which requires the running motor to stop before all other processes when the travel limit switch
is activated, never design a system in which the signals from the travel limit switch are input to the input
terminals of the GP and then processed using software.
Configure a circuit that reliably stops the running motor using hardware as shown below.
• After executing an internal program, the GP outputs ON/OFF information to the output devices
at the same time. For example, the electromagnetic switches for forward and reverse rotation of
a motor are turned on and off at the same time.
Consequently, a situation may arise in which both of the main contacts of the motor circuits for
the electromagnetic switches for forward and reverse rotation may turn on, causing a short-cir-
cuit of the R and T phases. To avoid this situation, you need to provide the interlock circuit
shown above or use an electromagnetic switch equipped with a mechanical interlock for a for-
ward/reverse circuit.
GP
Running motor control signal
Travel limit switch
Running motor
control circuit
Emergency
stop switch Travel limit
switch
Direct input to the emer-
gency stop circuit of the
control unit