I am referring to the aftermath of the great electric short circuit, which destroyed an RS-232 to RS-485 converter. After going over all of the physical stuff, and swapping out the Modicon PLC (node 11, slots 3, 4, & 5), it seems we are having intermittent Modbus communication failures.
The two Optomux-clone nodes, which are on the same RS-485 network, are working fine. But on occasion, the DR3 driver returns a CRC error - saying the calculated CRC of the reply message from the PLC, does not match the actual CRC included in the same reply message.
Now, I had seen this before, during SPOCS 2.2 development, and thought I had fixed it. Looks like I need to look more closely at DR3, or maybe the interaction between DR3 and driver DR1.
I looked at the SPOCS page over on SourceForge today. 360 downloads, and now we are picking up references in tweets, and "likes" on Facebook! Thanks to everyone who "liked" SPOCS!