EPM 2200 POWER METER – INSTRUCTION MANUAL 7–1
EPM 2200 Power Meter
Chapter 7: Com Option B: BACnet
MS/TP with Modbus
TCP/IP
GE
Grid Solutions
Com Opt ion B: BACnet M S/TP wit h Modbus TCP/IP
The Communication Options available for the EPM 2200 are connected and used in
different ways.
• Com Option S: Modbus/KYZ output is explained in Chapter 5 on page 5-1.
• Com Option B: BACnet MS/TP with Modbus TCP/IP Internet is explained in here in
Chapter 7.
7.1 BACnet MS/TP
BACnet is a data communication protocol developed for Building Control applications in
1987. BACnet allows applications to process data from many different kinds of equipment
and manufacturers. Originally it was used for HVAC control systems, but it has been
extended to other building systems, including lighting and energy management. Today
BACnet is one of the two most widely used Building Automation protocols in use. It is an
ASHRAE/ANSI/ISO standard protocol.
The BACnet protocol consists of Objects that contain different kinds of information. Each
Object has properties that contain data related to it. Below is the example of an Object for
Total Watts:
• Object_Name, PWR_ELEC
• Object_Type, Analog Input
• Object_Instance, AI-101018
• Present_Value, watt, tot (value in watts)
BACnet operates in a client-server environment. A client machine sends a service request
(message) to a server machine; once the service is performed the results are reported back
to the client machine. BACnet defines 5 groups (or classes) of 35 message types. For
example, one class contains messages for retrieving and manipulating the object
properties described above. An example of a common service request in this class is
"ReadProperty." When the server machine receives this message from a client machine, it
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