Troubleshooting Bacnet Ms/Tp Communication - United Technologies Carrier Unit Vent Open Integration Manual

On the Communication screen, edit the fields as needed:
Click the property box next to BACnet Device Instance, type the new number, and click Done.
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Click the property box next to Max Masters and/or Max Info Frames, type a new value (1-127), and click
8
Done.
Click Save.
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Troubleshooting BACnet MS/TP communication

For detailed troubleshooting and a list of supported objects, get the controller's BACnet PICS from the Carrier
BACnet PICS website http://www.bacnetinternational.net/catalog/index.php?m=28. You must get your BACnet
Object list from the manufacturer.
The most common communication problems are the result of not properly following the configuration steps
outlined in this manual. Review all of the steps and use the following list to check your settings.
Verify accuracy of the following:
Hardware settings for BACnet MS/TP (8 Data bits, No Parity, and 1 Stop bit):

Baud rate DIP switches 1 and 2

BACnet MS/TP protocol DIP switches 3 and 4

Jumper set to EIA-485

Proper connection wiring

Unique rotary address switches 1 – 99. If controllers have duplicate addresses, network communication can
be lost.

Unique BACnet Device Instance numbers. Default is 16101XX, with the rotary address switches defining XX. If
controllers have duplicate device instance numbers, network communication can be lost.
NOTES

The controller recognizes physical changes (DIP switches, rotary switches, and jumpers) upon power up.

If RX LED is solid, then the terminations are incorrect.

If the network has greater than 32 devices or exceeds 2,000 feet, a Repeater should be installed.

If a controller begins or ends a network segment, a terminating resistor may be needed.
Unit Ventilator
Integration Guide
7
Communications wiring
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