Schneider Tricon systems are PLCs intended for use in safeguarding applications. They are triple modular redundant (TMR) and TÜV-certified for SIL 3 applications to international standard IEC61508:2010.

In addition to supporting Modbus, they also have their own proprietary (but published) protocol known as Triconex System Access Application (TSAA). This provides similar functionality to Modbus, but allows reading and writing to tags to be based on tagname rather than an address by exporting an XML file from their Tristation development software and uploading it to the TSAA server.

Their fully published specification can be found on Google by searching for “Triconex Communication Guide”, and referring to the PDF appendix titled TSAA Protocol.

This protocol is supported by MatrikonOPC server, Kepware OPC server, and TOP server OPC.

However, rather than having multiple protocol converting servers between the HMI and PLC, it would be great if this was natively supported within Ignition HMI. This product is heavily used in oil and gas, and nuclear industries.