Communication with M-Bus
A43/A44 274 2CMC48001M0201
User Manual Revision: C
10.5 Sending Data to the Meter
General This section describes the telegrams that can be sent to an EQ meter. Some of the
telegrams contain data, others do not. Data sent in the telegram is sometimes
stored in the meter, sometimes used by the meter to perform a certain action.
Telegrams that contains no data usually initiates a certain action in the meter.
Write access
level protection
Some of the commands can be protected by a password. There are 3
different levels of write access level protection:
• Open
• Open by password
• Closed
10.5.1 Set tariff
The write access level can be set either via the buttons directly on the meter or
via communication using the set write access level command.
If the access level is set to Open, the meter will always accept the command as
long as the the meter is properly addressed and the syntax and checksum are
cor-rect.
If the access level is set to Open by password the specific command sent to the
meter must be preceded by a send password command in order for the meter to
accept the command.
If the access level is set to Closed the meter will not accept any command, but will
just return an acknowledge character (E5 hex). To change this access level pro-
tection, the access level has to be set to Open via the buttons directly on the meter.
Note – Commands that are not affected by the write access level protection only require
a correct message with correct address, syntax and checksum to be accepted.
For meters with tariff control the active tariff is set by sending the following
com-mand (all values are hexadecimal). The command is not affected by the
write protection level set.
L-field, calculated from C field to last user data
CI-field, data send, LSB first
VIF next byte is manufacturer specific
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