Why is there no safe communication protocol (SIL 2/3) for Modbus?


Thread Starter


There is ProfiSAFE for Profinet/bus, Failsafe over Ethercat (FSoE), Opensafety for Powerlink, but nothing tangible in the way of Modbus, although opensafety claims this could work.

I've read somewhere on this forum that Modbus is not suitable for safety application. Any source (books, research etc) on this?

More importantly, are there any workarounds to make modbus capable of SIL 2/3?

>More importantly, are there any workarounds to make modbus
>capable of SIL 2/3?

I could be wrong, it was many years ago working with SIL levels. At the time, IIRC, if the MODBUS communication cable was in the same cabinet you could achieve X SIL level and if the cable had to route between cabinets the cable had to be in conduit, not cable tray, to achieve X SIL level.

But, it could have changed over the years and not possible in 2018.

And it might only apply to complete systems that are tested/certified not out of the box solutions.

Good luck,