Agilent Technologies Turbo-V 301-AG Notice De Mode D'emploi page 281

So, if the first byte is equal to 0, the interface is working properly,
otherwise there is a problem.
Each nibble in the bytes following the interface status byte represents
the status of the last attempt to write a parameter with following
coding (diag status byte):
0
1
2
3
4
5
6
F
The ProfiBus external diagnosis services are used to report following
unexpected situations:


Turbo-V 301-AG Rack Controller User Manual / 87-900-982-01 (I)
Write success
Controller response was "NACK"
Controller response was "Unknown window"
Controller response was "Bad Data Type"
Controller response was "Over range"
Controller response was "Bad operation"
Controller response was an unknown response
Parameter not supported by the controller
Controller fail: if the controller goes in fail mode, an external
diagnostic service is required and one byte in the diagnostic
buffer signals the type of failure.
User parameter mismatch: if the user sets one or more
parameters out of their allowed range, a ProfiBus external
diagnostic service is required and some bits in the diagnosis
frame signals which parameter is wrong (i.e. over range or under
range).
Technical Information
Profibus Option
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