Communication with M-Bus
A43/A44 238 2CMC48001M0201
User Manual Revision: C
10.4.2 Readout of Demand Data
Read request A read request is performed by sending the following SND_UD to the meter fol-lowed by a
REQ_UD2 (all values are hexadecimal).
L-field, calculated from C field to last user data
CI-field, data send, LSB first
VIF time point, date, M-Bus data type G
VIF next byte is manufacturer specific
VIF extension of manufacturer specific VIFE's, next
VIFE specifies actual meaning.
VIFE specifies maximum demand
Date (M-Bus data type G, LSB byte sent first)
CS checksum, calculated from C field to last data
Comments The demand data stored for a measured period is sent out in one or more telegrams
depending on the number of channels that are used. The data that is sent out is
interval and subinterval length, demand values for all channels and a date/time
stamp for the end of the measured period. Each demand value is also followed by
the date/time stamp for the end of the interval in which the minimum/maximum
occurred.
The date/time information is sent out in format 6 byte BCD in order second, min-
ute, hour, day, month and year.
The data for the currently pending period will be sent out with storage number
set to 0, the most recent stored historical values will have storage number 1, the
next set of historical values will have storage number 2 etc.
If data have not been generated for a quantity the demand value is set to 0 and
status “data not available” (15 hex) and the date/time is set to 00-01-01 / 00:00:00.
This is the case for the currently pending period before any demand have been
stored, that is while the very first interval in a measurement period is pending. It
will also happen if a particular tariff has not been active in a measurement period.
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