D397-51-880 Issue E
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OPERATION
4.6.4 Diagnostics description
The modules use extended diagnostics in the format below.
Max_Diag_Data_Len = 12
Loss of serial comms may be due to the SCU being turned off or the RS232 cable being disconnected. It will take up
to 9 seconds to detect. If this occurs the Slave will signal the Master with a ‘Data High’ flag in the Frame Control byte
but will continue to be in Data Exchange with the data values all set to zero. The extended diagnostics message will
be available to the Master.
If RS232 communications are restored the Slave will again signal the Master with a ‘Data High’ flag in the Frame
Control byte and will return to ‘good’ Data Exchange values. Again the extended diagnostics message will be available
to the Master.
4.6.5 Data exchange values
Data update rate (latency) is fixed and not affected by which software modules are included in the Data Exchange
message. The update rate is not the same for all parameters and will be up to 9 seconds for some parameters.
At the beginning of Data Exchange, particularly but not only, when Data Exchange has started due to power up of
either the Turbo control unit or the Profibus Module or due to RS-232 cable reconnection, the data values will either
be old or zero. These values will be successively corrected over the first few seconds of Data Exchange. For some
parameters this process will take up to 9 seconds.
Bytes 1-6 7 8 and 8 10 and 11 12
Description
Mandatory No of bytes of
extended
diagnostics (6)
Module failed
parameterisation,
MSB in 8, LSB in 9
Module failed
configuration,
MSB in 10, LSB in
11
Serial comms
lost (0=OK,
1=lost)
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