Siemens SINAMICS V20 Operating Instructions Manual page 193

Parameter scaling
Due to the limits of the integer data in the MODBUS protocol, it is necessary to convert the
converter parameters before transmitting them. This is done by scaling, so that a parameter,
which has a position after decimal point, is multiplied by a factor, to get rid of the fractional
part. The scaling factor is as defined in the above table.
BICO parameters
The updating of BICO parameters will also be done in the parameter processing in the
background. Because of the limitations of the register value, it is only possible to write a '0'
or a '1' to a BICO parameter. This will set BICO input to a static value of either '0' or '1'. The
previous connection to another parameter is lost. Reading the BICO parameter will return the
current value of the BICO output.
For example: MODBUS register number 40200. Writing a value 0 or 1 to that register will set
the BICO input P0731 statically to that value. Reading will return the BICO output, which is
stored in r0747.0.
Fault
The converter displays the fault F72 when the following three conditions are met:
● The parameter P2014 (USS/MODBUS telegram off time) is not equal to 0.
● Process data has been received from the master since the converter's start-up.
● The time between receipts of two consecutive process data telegrams exceeds the value
of P2014.
SINAMICS V20 Converter
Operating Instructions, 10/2019, A5E34559884-012
Communicating with the PLC
7.2 MODBUS communication
191