I’m writing an app in C# for Windows 10 IOT on a Raspberry Pi. I have implemented the API command set. The software connects to an FR8x relay board by TCP using one of two different paths that both exhibit the same problem. One path uses the Lantronix communication module directly, and the other uses the RS-232 communications module connected to a Digi PortServer TS. (We have used the Digi products and NCD relay boards successfully for more than a decade.)
The problem I am seeing is that the board intermittently fails to respond to status queries (DEC 124). The fact that the problem exists on both pathways leads me to believe that either (a) the command is being corrupted enroute, or (b) the board is either not receiving the command correctly or just not responding. TCP error detection would seem to make option (a) unlikely.
Is there a way to troubleshoot the problem further? Have you seen this issue before? The status queries are being sent at 2-second intervals to capture any relay settings that may have been changed by software using the alternate port. Is that interval rate too high? I’ve implemented a work-around, but the issue is consistent and I am curious about its origin.