Modbus/TCP in I/O Controller2 and IP Relay HWg-ER02b

Modbus/TCP settings are found in the MODBUS Setup menu:

Local Settings section

• @M: GPIO control from MODBUS – Activates or deactivates access via Modbus/TCP.
• @P: Port – TCP port where the device listens for Modbus/TCP communication.
• @I: Unit Identifier ("slave address") – Modbus Slave ID.

Active mode

In the Active mode, one device can control up to 8 slave devices (1:n operation). Just specify the IP address of the remote device, the Port where it listens and the Slave ID (Unit Identifier). At the remote device, Modbus/TCP must be activated.

Modbus register map

Box2Box mode over Modbus/TCP

The Box2Box mode can be used in in 1:1 or 1:n operation. In 1:1 operation, the inputs of an I/O Controller (IP Relay) can be mirrored on the other I/O Controller and vice versa; in 1:n operation, the inputs of one device can be mirrored on up to 8 other devices.

Master device

At the master device (that sends the data), GPIO control over ModBus/TCP must be enabled and the connection parameters for the target devices entered. It is necessary to specify the IP Address, Port, and Unit Identifier. In 1:1 operation, the settings are identical at both sides.

Slave side (1:N operation)