Endress+Hauser Liquiline CM44 series - Supported Function Codes

SD01189C/07/EN/04.17
Endress+Hauser
9
3.4 Supported Function codes
Function
code FCxx
Name
Description
03
READ HOLDING REGISTER
Reads one or more MODBUS slave registers.
1 to maximum 125 consecutive registers can be read
(1 register = 2 bytes) with one telegram.
Application:
Reads measuring device parameters with read and write
access.
04
READ INPUT REGISTER
This function code is used to read registers with read
access. Up to 125 consecutive registers can be read.
Application:
Reads measuring device parameters with read access.
08
DIAGNOSTICS
This function code is used to check the communication
between Master and Slave.
The following sub function codes are supported:
• Sub function 00 = Return query data (loopback)
• Sub function 02 = Return diagnostic register
16
WRITE MULTIPLE REGISTERS
Describes several slave registers using a new value.
Up to a maximum of 123 consecutive registers can be
described using a telegram.
All registers that are addressed using the written registers
must be writable, as otherwise the request may be
responded to with an ILLEGAL DATA VALUE exception.
23
READ/WRITE
MULTIPLE REGISTERS
Simultaneously reads and writes 1 to maximum 118
registers in one telegram. Write permission is granted
before read permission.
Broadcast messages are permitted only with function codes 06, 16 and 23. The function code 08 is
supported only for Modbus RS485.