Unable to write to Tstat8 in Bacnet

Ive moved my Tstat8’s over to Bacnet per recomendations here in another thread. Im able to read from the stats with no issues now.

Stats are all running 8.1 T3000 is Oct 26th. T3-BB is 48.0


If I go to “Advanced Setup” on the main Tstat config screen, I am unable to modify any settings. If I pick say powerup setpoint and change it from the default 68 to 70, it will turn red. I click apply, nothing happens. It stays red. If I click exit and go back to the menu, its still 70 and red. If I click on the stat again, to restablish connection, it will load again, I go into the menu and now its 68 again, but still red. This is just an example, I cannot change any settings.

If I click “Pid Table” and attempt to change the heating stages to “1”, the program freezes for a moment, sometimes longer, and I get a box that says “try again”. I can try again 100 times and it wont work. This happens on any of the five stats.

When I had the stats in Modbus mode I was able to do these things so Im not sure what the cause could be.

I am getting a small ammount of packet errors and timeouts on the RS485 bus these are attached to. Im not sure if this is related or not. Since restarting the counters last night the count is:
Rx 19604872
Tx 6991862
ID col 0
Packet error 26
Timeout 175

I dont know if I should suspect my RS485 wiring or if this is a software issue.

Thanks for the detailed troubleshooting report here, and after consulting with the team our best guess is that the poor communications is at play here. I can confirm that all the settings of the Tstat8 are available over the MSTP connection. The only caveat is that T3000 is using a proprietary block write command to read to the old Modbus register lists, there’s a lot of settings to deal with which don’t all have a native bacnet AV so this is how we’ve handled it for now.

The packet statistics look pretty good, only a few failed packets there. You could isolate the stat, just use one on the desktop as opposed to a long RS485 network with several devices to see if things improve. We use wireshark to see the MSTP traffic, you might get some clues from that. I wrote a blog entry on this site which shows how to caputure MSTP traffic using Wireshark.

Standing by to help.