×
Skip to main content Link Search Menu Expand Document (external link) Right Arrow

Contents

M-Bus

Meter-Bus (“M-Bus”) is an EN 13757-2/3 standard that is primarily intended for handling telemetry data from meters, i.e., for the measurement of water, gas, and electricity consumption. It is developed and maintained by the Cologne-based OMS-Group e. V.. While detailed documentation exists for the standard, it is currently outdated; applicable European Standards should be used for reference instead.

Being one of the most common standards in metering applications, a basic implementation of M-Bus comes bundled with the Edge server and can be used in the Cloud; note, however, that Wireless M-Bus, an extension of the protocol for data transmission over the air, is currently not supported.

Device Parameters

For device parameters not covered herein, see Device-Based Tags.

The Edge server may not communicate with M-bus devices directly and instead relies on an M-bus master device that carries a network of M-bus meters commonly referred to as “slaves”. An M-bus master often also functions as a level converter and may use secondary level converters to extend the M-bus network beyond its distance or device number capacity.

EnergyMachines™ can provide M-bus setup and configuration services on request; contact our support.

Connection Settings

Determine how the Edge server should connect to the target M-bus device. Two methods are available under Connection Type:

  • Serial
    Uses an RS232 / RS422 / RS485 port. The following parameters are used to establish a serial connection:
    • Port Name
      Port carrying the M-bus master.

    • Baud Rate
      Data transfer rate, in symbols per second (baud). Pursuant to the M-Bus specification, the Cloud supports baud rates of $ 300\times2^{0,1,2…7} $. The most commonly used baud rate is 2400, which is also the default value for M-bus devices in the Cloud.

      Selected baud rate must be supported by all the devices on the network.

    • Parity
      Sends a parity bit with each byte, which provides an error detection mechanism:
      • Odd. Each byte must contain an odd number of bits equal to 1, including the parity bit.
      • Even. Each byte must contain an even number of bits equal to 1, including the parity bit. This is the default option for most M-bus applications.
      • None. Parity bit is not sent; effectively disables error detection.
  • TCP
    Uses TCP/IP stack to connect to the M-bus master over the Ethernet:
    • Host Name
      TCP/IP host name or address of the target device/level converter on the local network. Defaults to localhost.
    • TCP port
      TCP/IP port of the M-bus master on the local network; defaults to 2000 if not specified.
    • TimeoutTime limit for establishing a connection to the M-bus master; defaults to 10 seconds if not specified. Connection attempt will terminate and issue a server alert if timed out.

Address settings

While connection setting concern the M-bus master as gateway to the M-bus network, the address identifies a particular slave device. Two address types are available:

  • Primary
    Single-byte address in range [1; 250] for networks of up to 250 meters; configurable per slave device and commonly allocated during device or network setup.

  • Secondary
    An eight-byte address that uniquely identifies a specific M-bus device worldwide. Secondary address is allocated by the device manufacturer and normally will not change during the device’s lifetime; it is commonly used in large M-bus networks where the primary address space is not sufficient to uniquely identify each slave device.

    Secondary address consists of an 8-digit Identification number, which matches the device’s serial number, and three two-digit segments: Manufacturer ID, Version, and Type, also referred to as “Medium”, in that order. Secondary address can be found in the device’s specification or data sheet.

Tag Parameters

For tag parameters not covered herein, see Tag Editor.

Index — M-Bus ID of the required data endpoint. Most meters only have one but allow setting it manually; consult the device’s user manual for details. Default value is 0.

For M-bus tags, there are no configuration parameters that would intrinsically determine the data type. Therefore, the external data type must be used to specify whether the data endpoint is expected to return a scalar or an array. An array data type must be selected to unlock the number of elements.

M-bus tags do not support writability.