Pepperl+Fuchs KFD HM 16 Series Manual page 53

HART Multiplexer System KFD*-HM*-16
Diagnosis and fault elimination
8.3.2 Structure of the first byte
Communication error
Note
Command responses
Note
If Bit 7 is set (1), the first status byte contains a summary of the communication
errors. This information is coded bit by bit.
If Bit 7 is cleared (0), the first status byte contains a summary of the command
responses. This information is numbered consecutively and not coded bit by bit.
This Byte contains information concerning the reception of a message.
The individual bits indicate a detected error, which has resulted in non-acceptance of
the message. Thus neither can a response be given to the message. It is necessary
to repeat the command, to check the connections, to use the terminating resistors or
to reduce the baud rate.
Bit
7 6 5 4 3 2 1 0
1
1 1
1 1
1 1
1 1
1 0
1 1
1 1 (undefined)
Details can be found in /1/.
The first byte contains information relating to the execution of a command. The
command-specific response code thus documents the execution of the command.
In contrast to the communication error, the command responses are not coded bit by
bit, but are numbered consecutively from 0 to 127.
Of the command responses signalled by the Multiplexer, two instances are warnings
(codes 8 and 31), in which the processing of the command is continued. In the other
cases, errors are indicated, that means that the initiating command could not be
correctly executed. Here, the remedy is given by the meaning of the code.
All the codes that occur on the HART system are described in /1/.
Meaning
Communication error, if Bit 7 = 1, coded bit by bit
Parity error
Overrun error
Message error
Checksum error
always 0 (reserved)
Input buffer overrun
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