compliance
Not compliant device can be time consuming!
Travis Atkinson of Com-Pac Filtration and me have worked together to find out why the HMI of Weintek Labs I-Series, with Ethernet, answered only to request sent by the modpoll program (proprietary software).
After many emails and the help of Wireshark, we have discovered modpoll uses the unit identifier as slave ID for TCP requests, according to the Modbus specs that’s incorrect (cf page 23 of Modbus Messaging Implementation Guide v1.
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