ABB A43

Communication with M-Bus
A43/A44 186 2CMC48001M0201
User Manual Revision: C
Data records
The data, together with information regarding coding, length and the type of data
is transmitted in data records. The maximum total length of the data records is 240
bytes.
The following table shows the structure of the data record (transmitted left to
right):
Data Record Header
Data
Data Information Block (DIB)
Value Information Block (VIB)
DIF
DIFE
VIF
VIFE
1 byte
0-10 bytes
1 byte
0-10 bytes
0-n bytes
Data information
block (DIB)
Each Data record consists of a data record header (DRH) and the actual data.
The DRH in turn consists of the data information block (DIB) to describe the
length, type and coding of the data, and the value information block (VIB) to
give the value of the unit and the multiplier.
The DIB contains at least one byte (Data Information Field, DIF), and is in some
cases expanded with, a maximum of 10, DIFE's (Data Information Field Exten-
sion).
The following table shows the structure of the Data Information Field (DIF):
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Extension bit
LSB
1
of storage No.
Function Field
Data Field
1. Least significant bit.
The following list explains the content of the DIF:
• The Extension Bit is set when the next byte is a DIFE.
• The LSB of storage No. is normally set to 0 to indicate actual value.
(1=stored value).
• The Function Field is set to 00 for instantaneous values, 01 for maximum
values and 10 for minimum values.
• The Data Field shows the format of the data. The following table shows
the coding of the data field:
Code
Meaning
Length
0000
No Data
0
0001
8 Bit Integer
1
0010
16 Bit Integer
2
0100
32 Bit Integer
4
0111
64 Bit Integer
8
1010
4 digit BCD
2
1011
6 digit BCD
3
1100
8 digit BCD
4