finder 7M Series - M-Bus

7M User’s Manual 30
5.2 M-Bus
The M-Bus interface fully complies with M-Bus European standard EN13757-2. The entire communication is ensured with 8
Data Bits, Even Parity, 1 Stop Bit and a Baud Rate from 300 to 9600 Bauds.
Communication settings
Default communication settings are: 2400, 8, E, 1 primary address 0 and secondary address is set to serial number of device.
Initialize M-Bus (SNK_NKE)
This Short Telegram initializes the M-Bus 7M.24. The M-Bus 7M.24 conrms correct receipt by Single Character
Acknowledgement (ACK = E5). If the telegram was not correctly received the 7M.24 will not send an acknowledgement.
Select 7M.24 M-BUS using Secondary Address (SND_UD)
This Telegram enables to select the 7M.24 M-Bus. The 7M.24 conrms the correct receipt by ACK. If the telegram has not been
correctly received the 7M.24 M-Bus will not send an Acknowledgement. After issue of the Single Character Acknowledgement
the 7M.24 M-Bus is ready to transmit the entire Read-out Data within 3 seconds from receiving the Telegram „Transmit Read-
out Data“. At the end of 3 seconds the M-Bus 7M.24 will switch back to normal mode.
Transmit Read-out Data via Primary/Secondary Address (REQ_UD2)
This Short Telegram enables to select the M-Bus 7M.24 and to command it to transmit the Read-out Data parameterized.
The M-Bus 7M.24 conrms correct receipt by transmitting of the Read-out Data. If the Short Telegram has not been received
correctly; no Data will be transmitted by the M-Bus 7M.24. The Read-out Data are sent within 35 ms – 75 ms from receipt of the
Short Telegram by the M-Bus Meter (fom more infomations see section M-Bus telegrams).
Set Baud Rate via Primary/Secondary Address (SND_UD)
This telegram enables to set the desired Baud Rate. The M-Bus 7M.24 conrms the correct receipt by ACK. If the telegram was
not received correctly the M-Bus 7M.24 does not send an Acknowledgement. The (ACK) is sent by the M-Bus 7M.24 in the
Old Baud Rate. As soon as ACK is transmitted the M-Bus Meter switches to the baud rate newly parameterized. If the 7M.24
now does not receive a new Telegram under the new baud rate within a period of 30 seconds – 40 seconds, it automatically
switches back to the old baud rate. This is apt to prevent that a faulty setting of the baud rate may interrupt communication.
Set Primary Address via Primary/Secondary Address (SND_UD)
This Telegram enables to set a new Primary Address. The M-Bus 7M.24 conrms the correct receipt by ACK. If the telegram has
not been correctly received the M-Bus 7M.24 will not send an Acknowledgement.
Set Secondary Address via Primary/Secondary Address (SND_UD)
This Telegram enables to set a new Secondary Address. The M-Bus 7M.24(M) conrms the correct receipt by ACK. If the
telegram has not been correctly received the M-Bus 7M.24 will not send an Acknowledgement.
Secondary Address (UD) consists of:
Identication Number: 00000000 – 99999999 8-digit Secondary Address number
Manufacturer’s Code: 73 26 2 Byte Company Constant (ISS = “73 26”)
Version Number: 01 – FF 1 Byte
Medium: 02 1 Byte Constant Electricit
Reset, Restart 7M.24 M-Bus via Primary/Secondary Address (SND_UD)
This Telegram reset/restarts the 7M.24 M-Bus. The 7M.24 M-Bus conrms correct receipt by ACK. If the telegram was not
correctly received the 7M.24 will not send an Acknowledgement.