Following the success of the original tGW-700/tDS-700 modules, ICPDAS has continued to develop new functions for these products in order to provide increased support for a greater number of applications. The tSH-700 module is a serial port sharer that provides a number of functions, including "Baud Rate Conversion", "Modbus RTU/ASCII Conversion" and "Two Masters Share One Slave".
The Baud Rate conversion allows a single master device to communicate with slave devices using different baud rates and data formats. Most query-response protocols (half-duplex), e.g. DCON, are supported in the raw data mode. Full-duplex communication should also work when the data size is smaller than the built-in 512 bytes buffer on each serial port. With the Modbus RTU/ASCII conversion a single Modbus RTU/ASCII master device can communicate with Modbus RTU/ASCII slave devices using different protocols, baud rates and data formats.
The function “Two Masters Share One Slave” allows two master devices connected to different serial ports to share slave devices. Modbus mode can be used to convert the Modbus RTU/ASCII protocols, while raw data mode can be used for DCON or other query-response protocols. Different baud rates and data formats can also be used on the different serial ports. The built-in cache function reduces the loading of serial communication on the slave port by removing duplicated queries when the two master devices are requesting the same information.
