Sub-
func‐
tion
code
(Dec)
Name
Description
13
Return Bus Exception Error
Count
The response data field returns the quantity of MODBUS ex‐
ception responses returned by the remote device since its last
restart, clear counters execution, or power–up.
14
Return Slave Message Count
The response data field returns the quantity of messages
broadcast or addressed to the remote device that the remote
device has processed since its last restart, clear counters exe‐
cution, or power–up.
15
Return Slave No Response
Count
The response data field returns the quantity of messages ad‐
dressed to the remote device for which it has returned no
response (neither a normal response nor an exception re‐
sponse), since its last restart, clear counters execution, or
power–up.
16
Return Slave NAK Count
The response data field returns the quantity of messages ad‐
dressed to the remote device for which it returned a Negative
Acknowledge (NAK) exception response, since its last restart,
clear counters execution, or power–up.
17
Return Slave Busy Count
The response data field returns the quantity of messages ad‐
dressed to the remote device for which it returned a Slave
Device Busy exception response, since its last restart, clear
counters execution, or power–up.
18
Return Bus Character Overrun
Count
The response data field returns the quantity of messages ad‐
dressed to the remote device that it could not handle due to a
character overrun condition, since its last restart, clear coun‐
ters execution, or power–up.
20
Clear Overrun Counter and Flag Clears the overrun error counter and resets the error flag.
Function code 8 example
Query
Slave address
1 byte
Function
1 byte
Sub-function Hi
1 byte
Sub-function Lo
1 byte
Data Hi
1 byte
Data Lo
1 byte
:
:
Data Hi
1 byte
Data Lo
1 byte
CRC
2 bytes
Response
Slave address
1 byte
Function
1 byte
Modbus communication FCT010
C.2 Modbus function codes
SITRANS MASS 2100 & FC300 (FCT010/DSL)
Operating Instructions, 06/2020, A5E39788682-AB
155