As part of a project-based automation of two redundant controllers TSXH57 24 million Unity Pro XLS V7.0 We want to read the status and control of a circuit breaker (third party product) Modbus RTU communicating. The communication between the controller through the Ethernet card and the breaker ETY5103 this fact by a communication gateway TSX ETG 100 (see figure below) via an I / O scanning: - IP address 192.168.1.5 PLC - IP address 192.168.1.34 pasrelle - Slave address: 2 CB control is done well, but we encountered a problem reading the input register (AI): circuit breaker status register which is normally done by the Modbus function 04. The I / O scanning does not support the Modbus function 04.
Indeed it is not possible to read input words% IW from a ETY5103 IoScanner.
The only solution is to use a READ_VAR block with syntax like the example below: