Siemens Milltronics SF 500 Instruction Manual page 97

SF 500 uses the following exception codes:
Code
01 Illegal Function
02 Illegal Data Address
03 Illegal Data Value
04 Slave Device Failure
05 Acknowledge
06 Slave Device Busy
08 Memory Parity Error
Error Handling
Errors can be divided up into two general sources. Either:
1. There is an error in transmission
2. The user tries to do something that is not a valid action
In the first case, the SF 500 will, not respond and let the master wait for a response time
out error, which will cause the master to re-send the message.
In the second case, it depends on what the user tries to do. Listed below are various
actions and what the expected outcome is. In general, SF 500 will not give an error to the
user request.
• If the user reads an invalid parameter, the user will get a number back.
• If the user writes an invalid parameter (a non-existing parameter or a read only
parameter), the value will be ignored and no error response will be made. However,
the current value will not reflect the desired new value.
• If the user writes a read only register, then the value will be ignored and no error
response will be made. However, the current value will not reflect the desired new
value.
• If the user attempts to write one or more registers that are out of range, an
exception response code 2 will be generated.
• If using an unsupported function code, undocumented results may occur. The user
is encouraged not to do this.
7ML19985CN01
Name
The function code received in the query is not an
allowable action for the slave.
The data address received in the query is not an
allowable address for the slave.
A value contained in the query data filed is not an allow-
able value of the salve.
An unrecoverable error occurred while the slave was
attempting to perform the requested action.
The slave has accepted a request and is processing it,
but a long duration of time is required.
The slave is processing a long-duration program com-
mand.
The slave attempted to read extended memory, but
detected a parity error in the memory. Service may be
required on the slave.
or
Milltronics SF 500 - INSTRUCTION MANUAL
Meaning
Page 91