BACnet System Integration troubleshooting guide - Metasys - LIT-1201531 - System Integration - BACnet Controller Integration - 10.1

BACnet Controller Integration Technical Bulletin

Product name
BACnet Controller Integration
Document type
Technical Bulletin
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Use the information in Table 1 to assist in diagnosing and solving possible BACnet System Integration problems.

Table 1. BACnet System Integration Troubleshooting Guide




Field devices appear to periodically cycle online and offline to the network engine as reported on the Site Management Portal UI. However, the field devices may actually be online the entire time

The network engine is too busy with some other tasks, misses a token pass, and is dropped from the token loop. By the time the engine rejoins the token loop, the engine has already flagged its field devices as offline.

Refer to the section Adjusting NAE network sensitivity in the NAE Commissioning Guide (LIT-1201519).

Auto discovery fails to find all devices.

Verify that the supervisory controller's Network Address and BACnet IP Port match that of the integrating IP-based BACnet devices. In the Device object Focus view, select Advanced to view the BACnet IP Port address.

If the BACnet device is on the MS/TP Field Bus, verify that the Network Address defined under the Hardware tab of the MS/TP Field Bus is correct.

Verify that no network devices have duplicated Object Identifiers. In accordance with the BACnet specification, the BACnet Object Identifier for each device on the entire network must be unique. After performing a Relearn, view the Duplicate Device Identifiers attribute of the BACnet Integration object (Diagnostic view). Any duplicates found on the network are listed.
Note: Duplicates of VMA1930 and FAC4911 devices will be included in list of discovered devices.

Verify that the BACnet Object Identifier of the supervisory controller itself does not conflict with that of the BACnet devices being integrated. The BACnet Object Identifier appears in the Focus view after selecting Advanced.

When Dynamic Broadcast Managment is enabled at the Site Director:

If the BACnet device is on a different IP network segment from any supervisory controller, specify a BACnet Broadcast Management Device (BBMD) for its segment. Add the device IP of a BBMD device in that segment to the third-party BBMD attribute of the Site object.

When Dynamic Broadcast Management is disabled at the Site Director:

Add all of the specified BBMD devices to the BBMD list of each JCI supervisory, field controller, or third party BBMD device. With Release 11.0 Metasys supervisory devices, you can enter either an IP address or a host name.

Verify that the BACnet device supports the Who-Is BACnet service. Auto discovery requires the support of this service.

COVs stop sending from a 3rd party device.

If the 3rd party device does not support the Restart Notification Recipients attribute and a reset occurs without being detected by the engine, the engine does not detect that this device went offline and does not resubscribe for change of values for up to 1 hour. The offline detection time from the engine is controlled by way of the Internode Delay.

Reduce the resubscription time to 300 seconds by updating the Resubscription Time attribute in the Subscription Client object. This is an internal object requiring SMP UI expert view.

A BACnet device goes offline and fails to come back online.

A change of the BACnet device IP address.

At startup of the supervisory controller, the BACnet Integration binds with the BACnet Object Identifier (OID) and uses the IP address from that bind. If you move a device to a different subnet, or change the IP address of the device, you must restart the NxE to bind the OID with the new IP address.

BACnet Trend Logs cannot be discovered.

The third-party Trend Log object does not support BACnet Logging Type (property 197) and returns an Unknown_ Property error when read.

Manually add the third-party Trend Log object to show the trend log attributes, and display the views and log data graph properly. See Adding a Trend Extension.

Attempts to write string attributes (such as Description) or if alarm acknowledgments from the SMP UI are not seen at the BACnet device.

Encoding type may be incorrect.

Verify that the BACnet Encoding Type specified in the Site matches the encoding that the BACnet devices are using: ANSI X3.4 (US-ASCII), ISO 10646 (UTF-8), ISO 10646 (UCS-2), or Microsoft DBCS Code Page 932.

Note: The UTF-8 BACnet Encoding Type is also compatible with ASCII as long as extended characters (for example, Ç, ä, ╣, and ß) are not used with ASCII devices.
Time sync or UTC time sync messages are not accepted.

The network engine accepts BACnet time sync messages only if no Simple Network Time Protocol (SNTP) server is defined for that network engine. If the device is a Site Director, do not enable (leave blank) the Site Time Servers attribute of the Site object.


If the device is not a Site Director, do not enable (leave blank) the Device Time Servers attribute of the Site object.


If the Time sync or UTC time sync message does not contain a specific time as required by BACnet (for example, message has wild card values), it is not accepted.