VENTURII

The next thing I needed to correct was that my model of PLC was not known to the library, so it left another variable, plc_mode, set to FINS_MODE_UNKNOWN. This too, caused communication functions to fail to send data, since they did not know what format to use. As a test, I modified the library to try using CV mode on my model of CPU, which it seemed to like as all the functions invoked after that returned much more meaningful return values, and tcpdump got a lot more excited... All of that appears correct to me. So why is libmodbus 3.0.8 and 3.1.6 both complaining that not enough bytes are in the message, and the promptly flushing all the missing bytes? Why can I find nothing online about this error message? Is no one else seeing results like this? Libmodbus is part of every major Linux distribution, so either no one is using it anymore, or it probably works just fine, leaving the problem back in my court. Could this be some OS level thing? Buffering, perhaps, of some kind?... What..