C1300
Advanced Circular Chart Recorder
6 Exception Responses
IM/C1300–MOD
Rev. C
13
6 Exception Responses
The exception response codes sent by the slave are shown in Table 6.1. When a slave detects one of these errors, it sends a
response message to the master consisting of slave address, function code, error code and error check fields.
6.1 Examples
A read register request to read holding register address 251 of slave 01 (undefined address for slave, beyond address limit) is shown
below.
The response returns exception response code 02, 'Illegal Data Address'. To indicate that the response is a notification of an error,
the most significant bit of the function code is set to 1.
Exception Response
Code
Exception Response Name
Exception Response Definition
01
Illegal Function
The message function received is not an allowable action for the C1300.
02
Illegal Data Address
The address reference in the data field is not an allowable address for the C1300.
03
Illegal Data Value
The value referenced in the data field is not allowable in the addressed slave location.
07
Negative Acknowledgment
The function just requested cannot be performed.
08
Memory Parity Error
Parity check indicates an error in one or more of the characters received.
Table 6.1 Exception Response Codes
Slave
Address
Function
Register Start Offset
Number of Registers
Error Check Field
(CRC-16)
High
Low
High
Low
01
03
00
FA
00
06
E5
F9
Slave Address
Function
Exception Code
Error Check Field
(CRC-16)
01
83
02
C0
F1
