TEC Series BACnet® MS/TP Network Temperature and Humidity Controllers Technical Bulletin
10
Troubleshooting
Table 2: Troubleshooting Details
1
1.
For common MS/TP troubleshooting information, refer to the
MS/TP Communications Bus
Technical Bulletin (LIT-12011034).
Symptom
Probable Causes
Multiple Symptoms
Excessive bus errors may be occurring.
A device may have been added or changed with a duplicate address
(may not be the same address as some devices having problems, and
may have happened sometime before the problem was noticed).
Wiring errors or wire problems may exist.
The baud rate may have been changed on some devices on the network
but not all devices.
Max_Master may have been changed incorrectly (may have happened
sometime before the problem was noticed).
A download may be in progress.
There may be a fault at a device.
A repeater may be needed or may be configured incorrectly.
There may be a duplicate device object name or instance.
Poor Performance
See the probable causes listed previously in the
Multiple Symptoms
section of this table.
Excessive bus traffic may exist (bus overload).
The baud rate may be set too low.
There may be too many devices on the network.
There may be unaccounted devices on the network (not mapped to the
NAE).
There may be unusually slow devices on the network or devices that are
slow to respond.
Controller Goes
Offline
See the probable causes listed previously in the
Multiple Symptoms
section of this table.
A power failure or other failure may have occurred at the controller.
Communication may have been disabled at the controller.
Controller Does Not
Come Online
See the probable causes listed previously in the
Multiple Symptoms
section of this table.
A controller may be connected to the wrong bus.
A baud rate may be specified in the new controller that is incompatible
with the running network.
No device on the network is configured to use a specific baud rate
(normally the NAE), but all devices are set to use auto baud. At least one
device, typically the bus supervisor (NAE), must have an assigned baud
rate. Set the baud rate in the bus supervisor and set all other devices to
auto baud.
