HRW HPE-BNMBUS V401 Manual 180307 E. & O. E. / Subject to change without notice
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Operation Overview
The gateway comprises two sections; the BACnet MS/TP device and the M-Bus network reading data
base.
BACnet Device
The gateway is BTL listed, conforming to the BACnet standard’s requirements for device & object
discovery and network communication initiations and responses.
During commissioning the following should be configured:
Node # (local network unique number)
Device Instance (system-wide unique number)
MS/TP network baud rate
Maximum Master (MM), set to the highest node number existing on the network, for limiting
network traffic to only those devices that exist on the network
250 AV objects relating to the M-Bus network devices’ data points being read, AV4…AV253
M-Bus Network Gateway
250 device data points may be configured, from up to 40 M-Bus devices. Each data point constitutes a
BACnet object (AV).
It is important to have the M-Bus device manufacturer’s manual available to assist with M-Bus point
address settings although the gateway’s Diagnostic function means the available data points can be
identified without the manufacturer’s manual if need be. Each required data point should be configured
in the order that it appears in the manufacturer’s point table (or in the order that they appear in the
Diagnostic response).
The gateway data base consists of:
1. One data point, the ‘DVIF’, which should be the first M-Bus user-required data point as it
appears in the data sequence. The data returned according to the DVIF point address may be
assigned to any AV that is configured as a meter addressing point
2. Starting with gateway point 4 (AV4) the first meter Primary or Secondary address point
3. Starting with point 5 (AV5) a sequential selection of required M-Bus data points related to the
preceding meter address point
4. Repeat step 2 & 3 for each subsequent M-Bus device
BACnet Priority Array
The BACnet protocol utilises a Priority Array for each object to enable various network devices to take
control of a device’s object based on the level of need. The priorities are in the range 1 (high priority) to
16 (Auto operation).
In respect of this device:
The point database objects are NULL priority, signified by ‘17’ when viewing the points in
engineering Terminal mode
Manually overriding a point value via terminal mode invokes priority level 9
Release of a manual results in an object reverting to NULL or next lowest and still valid priority
level if it has been commanded from another device in the system (such as the BMS)
For normal reading of the M-Bus network points should always be at NULL priority
