Sensor type
Sensor size
Default value kg/s
Zero offset limit
DN4 HP
2
0.0000972
DN4 C22
3
0.000264
DN4 316
3.5
0.000389
Sensor type
Sensor size
Default value kg/s
Default value kg/h
Low flow cut-off
DN4 HP
2
0.0000972
0.35
DN4 C22
3
0.000264
0.95
DN4 316
3.5
0.000389
1.4
B.3
Exception handling
There is a defined set of exception codes to be returned by slaves in the event of problems. All
exceptions are signalled in the response from the slave by adding 80 hex to the function code
of the request and following this byte by an exception code.
Table B-1
Exception codes
Exception
code (dec)
Exception text
Description
01
Illegal function
The function code received in the query is not an allowable
action for the slave
02
Illegal data address
The data address received in the query is not an allowable
address for the slave.
03
Illegal data value
A value contained in the query data field is not an allowable
value for the addressed location. This may indicate a fault in
the structure of the remainder of a complex request, such
that the implied length is incorrect or the number of registers
is too high.
04
Slave device failure
The request is for some other reason not acceptable. It may
e.g. indicate that the data value to write is evaluated to be
beyond limits.
B.4
Float definition
Stuffing of multi-byte numbers into multiple Modbus RTU registers differs among Modbus
devices. "Big Endian" and "Little Endian" describe the order or sequence in which multi-byte data
is stored in memory. This device uses (IEEE 741) a "Big-Endian" representation for addresses and
data items as default. This means that when a numerical quantity larger than a single byte is
transmitted, the MOST significant byte is sent first.
Technical reference
B.4 Float definition
SITRANS MASS 2100 & FC300 (FCT010/DSL)
146
Operating Instructions, 06/2020, A5E39788682-AB