User’s Manual 7M
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APPENDIX B: 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.38.8.400.XXXX.
The M-BUS 7M.38.8.400.XXXX confirms correct receipt by Single Character Acknowledgement (ACK = E5).
If the telegram was not correctly received the 7M.38.8.400.XXXX will not send an acknowledgement.
SELECT M-BUS 7M.38.8.400.XXXX USING SECONDARY ADDRESS (SND_UD)
This Telegram enables to select M-BUS 7M.38.8.400.XXXX. The M-BUS 7M.38.8.400.XXXX confirms the correct receipt by ACK.
If the telegram has not been correctly received the M-BUS 7M.38.8.400.XXXX will not send an Acknowledgement.
After issue of the Single Character Acknowledgement the M-BUS 7M.38.8.400.XXXX 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.38.8.400.XXXX 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.38.8.400.XXXX and to command it to transmit the Read-out Data
parameterized. The M-BUS 7M.38.8.400.XXXX confirms 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.38.8.400.XXXX.
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.38.8.400.XXXX confirms the correct receipt by ACK.
If the telegram was not received correctly the M-BUS 7M.38.8.400.XXXX does not send an Acknowledgement.
The (ACK) is sent by the M-BUS 7M.38.8.400.XXXX 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.38.8.400.XXXX 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.38.8.400.XXXX confirms the correct receipt by ACK.
If the telegram has not been correctly received the M-BUS 7M.38.8.400.XXXX 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.38.8.400.XXXX confirms the correct receipt by ACK.
If the telegram has not been correctly received the M-BUS 7M.38.8.400.XXXX will not send an Acknowledgement.
Secondary Address (UD) consists of:
Identification 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
