Profibus Communication
B.6 Diagnostics
SITRANS F M TRANSMAG 2
98
Operating Instructions, 11/2009, A5E00102775-07
The "Diag_Flag" is always set when something has changed in the last four bytes of the
diagnostic data (corresponds to the parameter "DIAGNOSIS") since the last message, i.e.
even when diagnostic messages disappear again so that the master can register every
change in the diagnostic data.
When a diagnostic message is active, the corresponding bit is set otherwise reset.
The following bits of the external diagnostic data are supported by SITRANS F M (all other
bits stay reset at all times):
Table B- 9
Format of the diagnostic data, byte 4
Bit No.
Description
Meaning
0
Error appears
At least one bit of the following 4 bytes (DIAGNOSIS)
was set
1
Reset
At least one bit of the following 4 bytes (DIAGNOSIS)
was reset
2 ... 7
Reserved
---
The "Error appears" message has priority over the "Error disappears" message, i.e. if one
diagnostic bit is set and another reset simultaneously, "Error appears" is reported.
The DIAGNOSIS part contains diagnostic messages of the device and has the following
structure (Bit 0 = LSB, Bit 7 = MSB):
Table B- 10 Format of the diagnostic data, Byte 5 (=DIAGNOSIS Byte 1)
Bit No.
Description
Meaning
Cause (local message)
"Com.--Module failure"
Communications module cannot be addressed
Sensor failure (sensor failure)
0
DIA_HW_ELETR
Hardware failure of the
electronic
"Measurement module failure"
4
DIA_MEM_CHKSUM
Memory error
Memory failure"
Flow measurement failure"
"Tube empty"
5
DIA_MEASUREMENT
Measurement failure
"Measuring range overflow"
Table B- 11 Format of diagnostic data, Byte 8 (=DIAGNOSIS Byte 4)
Bit No.
Description
Meaning
Cause (local message)
0 ... 6
reserved
---
7
EXTENSION_
AVAILABLE
More diagnosis
information is available
More diagnosis information available (here:
Local messages see DIAGNOSIS--Byte 1)
The bits in DIAGNOSIS usually take over the function of a group message which can then
be split up in detail using the local messages.
The EXTENSION_AVAILABLE bits indicates that other diagnostic information is available,
basically details of the DIAGNOSIS message. This information is displayed locally.
Additionally, the measured value-related messages are transmitted cyclically with the
measured values in the status byte (Substatus).