Schneider Electric iEM3200 Manuale Utente
iEM3100 / iEM3200 / iEM3300 series user manual
Communications via M-Bus
DOCA0005EN-04
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Chapter 7
Communications via M-Bus
What is in this chapter?
This chapter contains the following sections:
M-Bus communications overview
M-Bus is a master / slave communications protocol where the master initiates transactions and the
slave(s) respond with the requested information or action. Data is transferred using hexadecimal
telegrams.
slave(s) respond with the requested information or action. Data is transferred using hexadecimal
telegrams.
Communications via M-Bus protocol is available on the iEM3135, iEM3235 and iEM3335.
The information in this section is intended for users with an advanced understanding of M-Bus
protocol, their communications network and their power system.
protocol, their communications network and their power system.
Configuring basic communications settings
Before communicating with the meter via M-Bus protocol, use the HMI to configure the following
settings:
settings:
Key terms
Setting
Possible values
Baud rate
300
600
1200
2400
4800
9600
600
1200
2400
4800
9600
Primary address
1–250
Term
Definition
C-Field
The control or function field of the telegram. It provides information about the telegram, such as the
direction of data flow (master to slave or slave to master), the status of the data flow and the
function of the message.
direction of data flow (master to slave or slave to master), the status of the data flow and the
function of the message.
CI-Field
The control information field of the telegram. It defines the type and sequence of data to be
transmitted.
transmitted.
Fixed data header
Contains device and manufacturer identification information.
DIF
Data information field. The DIF contains information about the function of the data (for example,
instantaneous versus maximum) and the data format (for example, 16-bit integer).
instantaneous versus maximum) and the data format (for example, 16-bit integer).
DIFE
Data information field extension. A DIFE contain additional information about the data, such as tariff
and subunit.
and subunit.
Master
A device that issues commands and receives responses from slave devices. There can be only one
master per serial network.
master per serial network.
Slave
A device that provides information or performs actions in response to requests from the master.
VIF / VIFE
Value information field and value information field extension. The VIF and VIFE contain information
about the value (for example, whether it is an energy or power value).
The meter uses both primary VIFE (as detailed in the M-Bus protocol documentation) and
manufacturer-specific VIFE.
about the value (for example, whether it is an energy or power value).
The meter uses both primary VIFE (as detailed in the M-Bus protocol documentation) and
manufacturer-specific VIFE.