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GASSONIC OBSERVER-i
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6.5.1. Exception
Responses
Byte
Modbus
Range
Referenced to
Gassonic
Observer-i
1
st
Slave Address
1-247* (Decimal) Gassonic Observer-i ID (Address)
2
nd
Function Code
83 or 86 (Hex)
MSB is set with Function Code
3
rd
Exception Code 01 - 06 (Hex)
Appropriate Exception Code (See
below)
4
th
CRC Lo
00-FF (Hex)
CRC Lo Byte
5
th
CRC Hi
00-FF (Hex)
CRC Hi Byte
Table 10: Exception responses
6.5.2. Exception Code Field
In a normal response, the Gassonic Observer-i returns data and status in the data field, requested in
the query from the master. In an exception response, the Gassonic Observer-i returns an exception
code in the data field, which describes the condition that caused the exception. Below is a list of
exception codes that are supported by the Gassonic Observer-i:
Code
Name
Description
01
Illegal Function
The function code received in the query is not an
allowable action for the Gassonic Observer-i.
02
Illegal Data Address
The data address received in the query is not an
allowable address for the Gassonic Observer-i.
03
Illegal Data Value
A value contained in the query data field is not an
allowable value for the Gassonic Observer-i.
04
Slave Device Failure
An unrecoverable error occurred while the
Gassonic Observer-i was attempting to perform the
requested action.
05
Acknowledge
The Gassonic Observer-i has accepted the request
and is processing it, but a long duration of time will
be required. This response is returned to prevent a
timeout error from occurring in the master.
06
Device Busy
The Gassonic Observer-i is engaged in processing
a long-duration program command. The master
should retransmit the message later when the slave
is free.
Table 11: Exception Code Field