What can cause this? Read shows correct values but subscribe is not?
Maybe start with a Wireshark capture.
It would also be useful to see your Modbus Address mapping configuration (though I recommend you don't use that at all if you can avoid it).
Ok, now with both of those tags still subscribed in the Quick Client, start a Wireshark capture, then initiate a read for the single tag. Both requests should be in the capture. Upload it here.
You need to save the PCAP file and upload that. A screenshot does no good.
Analysis.pcapng (2.1 MB)
Here is the file
Modbus device address: 10.175.133.38
I don't see anything strange, but in this capture the single read you did looks to have been for "OPA1" and not "OPA3" like in your screenshot.
Analysis.pcapng (3.3 MB)
I clicked on both tags reads in this
Your device seems to return different data for the same registers depending on how many overall register are being read.
Reading Input Registers 0-7:
Reading Input Registers 2-3:
Note the different values returned for 2 and 3 between the two screenshots...
Seems like you should be talking to the vendor of this device about its buggy implementation.
When you click Read it sends a request for just the 2 registers needed for that tag.
With your subscribed tags, all 8 of the sequential registers needed are bundled into a single request.
I split the definition into multiple address mapping categories and that seemed to work.