Specifications

RS-485 Network Congurations
The RS-485 Section can be configured in three ways:
• Pulse Out Only – RS-485-OFF
• Modbus
• BACnet
The following sections explain each in detail.
RS-485 Network Configuration – Pulse Out Only
Figure 28: Pulse Out Only Option
If the Modbus or BACnet communications are not going to be used, the Pulse Out Only setting can be selected. This will
disable the RS-485 Network.
RS-485 Network Configuration – Modbus
Figure 29: Modbus Option
Select Modbus, to access the Modbus pull down menus.
Select the Address, Bit Rate (Baud Rate) and Mode (RTU or ASCII).
The 340 BN/MB Btu Energy Transmitter uses IEEE 754 Float - Data Located in “Holding Registers.”
The 340BN/MB Data Format is “Float 32” where the Data is stored across two “Holding Registers”.
In the case of Temperature 1, the Upper Byte is stored in Register 40002, and the Lower Byte is stored in Register 40001,
sometimes referred to as an ABCD to CDAB format. This is done to permit backwards compatibility with older 16-bit systems.
For example, a temperature of 53.36° F when converted to IEEE 754 is “425570A4.” So in the case of the 340BN/MB,
Register # 40001 = 70A4 Hex and Register # 40002 = 4255 Hex. See the table on the next page for additional information.
Data Industrial® 340 BN/MB BTU Energy Transmitter
Page 20 July 2012