Surge Protector for Digital Ports of PLC Controller

SUG-IO24/DIN is a surge protector used in industrial automation to protect digital input or output ports in PLC controllers. It can be used wherever the control current does not exceed 300mA (including pulses) and the control voltage does not exceed 24V DC.

In case of the need for surge protection of high-current outputs, for example for controlling contactors, a typical power supply protector should be used, model SUG-24VDC/DIN.

Modern solutions in the form of MOSFET fuses limit the flow of large surge currents through the protector, resulting in increased durability and significant reduction of the surge voltage reaching the protected device. An additional advantage of this solution is the limitation of equalizing currents, which can protect digital ports from potential jumps that lead to overcurrent.

In the case of protecting the input ports of a PLC controller, the product protects one input (signal + ground) and additionally the wire shield. If the output port protection does not require a shield, then the shield terminal can be treated as the power ground and channels 1 and 2 as two independent protective circuits. This way, two output ports can be protected with a common ground.

Built-in additional protective circuit of the cable screen can be indirectly grounded through a gas discharge tube (GDT) or directly to the ground. Connecting terminals 3 and 4 closes the connection of the cable screen to the ground.

The surge protector is designed for mounting on a DIN rail of 35mm. High-quality window terminals with high current load reduce the risk of damage during large surge impulses and temporary current overloads. The device occupies the width of one standard DIN module.

The product is designed for installation at the boundary of LPZ0 and LPZ1 zones or higher. It can be used with a voltage of 24V, including with an alternating component, as it can transmit fast data transmissions.

Simplified internal diagram.

To ensure proper surge protection, it is recommended to use protectors at both ends of the power line and to properly ground them.

Example of surge protection for PLC input with shielded cable.

Example of using surge protection for two PLC outputs
with the use of a shield circuit as a common ground

Technical specifications