ABB A43, User Manual

Page: 121 / 295

Communication with Modbus
2CMC48001M0201
121 A43/A44
Revision: C User Manual
Function Size Description Data type Read
/write
Data type 1 Data type for the value of the quantity Unsigned R/W
concerned
Scaler 1 Scaling of the value for the quantity concerned Signed R/W
Timestamp
The date and time on which the value was stored. How to interpret the data in
these registers is described in. “Date and time format” on page - 117
Quantity registers
The OBIS code for a quantity in for example a load profile channel or previous
values channel. A list of OBIS codes is found in “Quantity identifiers” on page
- 117.
The table below shows an example of how an OBIS code is mapped to
the Quantity registers. The OBIS code used is for active energy import
total: 1.0.1.8.0.255.
Byte Comment on byte order Value (in case of active
number energy import total)
0 Most significant byte of lowest register 1
1 Least significant byte of lowest register 0
2 ... 1
3 ... 8
4 ... 0
5 Least significant byte of highest register 255
Data type register The data type register contains a data type identifier that is a value between 0 and 255.
Currently only two identifiers are used for historical values. The identifier for 64 bit
unsigned integer is 21 and the identifier for 64 bit signed integer is 20.
Scaler register
The scaler register shows the resolution of the value. The measured value in the Value
register should be interpreted as value*10
scaler
. For example, the prefix kilo
is represented by scaler 3 while milli is -3. An energy accumulator with
the resolution 0,01 kWh consequently has scaler 1.