One would think one should be able to daisy chain some devices, no? Certainly in our deployments we have daisy chained RS485 modbus devices and not encountered this. I don't dispute that your description sure does sound like it would eliminate any possibility of getting the issue, but it doesn't seem like it should be necessary. I do agree that it'll be the fastest, easiest path to resolution, though, since no more investigation would be called for.
I edited out Ed's email address. Partially because I don't know what Ed would like an Email about, and partially because I don't know Ed would like emails from anyone who wanders by.
I wonder if you're seeing two registers on the same slave ID cross, two slaves cross in the same register, or two different registers from two different slaves cross?
Judging from your configuration alone, nothing seems too unusual. My first question is if your serial data source reset logic would fire three times for this data source should the data source stop polling (I think it would, to hopefully no effect, but quite interesting). I may also try things like
lowering retries to 1, lowering max read registers to 1 (for 2 byte data types, 2 for 4, 4 for 8) and unchecking contiguous batches Enabling data source alarms at a higher level than None, such that you notice if there's an ongoing error in polling. (For the version of Mango you're on, likely the only place you could see None level events is by directly querying the database's events table)I may try to reference times your reset script had fired against moments of crossed data, also, because that script seems unusual to me.