TMT84 Troubleshooting
Endress+Hauser 37
9.2.3 Display in the PROFIBUS
®
master system (cyclical data transfer)
If the AI module is configured for cyclical data transfer, the device status is coded according to
PROFIBUS profile specification 3.02
2)
and transferred, together with the measured value via the
quality byte (byte 5), to the PROFIBUS master (class 1). The quality byte is divided into the segments
quality status, quality substatus and limits (limit values).
a0002707-en
Fig. 15: Structure of the quality byte
The contents of the quality byte of an analog input function block depends on its configured failsafe
mode. Depending on the failsafe mode configured in the FAILSAFE MODE function, the following
status information is transferred to the PROFIBUS master (class 1) via the quality byte:
FAILSAFE MODE as per profile 3.01
When you select FAILSAFE MODE È FAILSAFE VALUE:
When you select FAILSAFE MODE È LAST GOOD VALUE (default value)
When you select FAILSAFE MODE È WRONG VALUE: status messages ( ä 38).
!
Note!
The FAILSAFE MODE function can be configured in the relevant analog input function block, i.e.
1 to 4, using an operating program (e.g. FieldCare).
2) As per profile 3.01: profile GSD files used or IDENT_NUMBER_SELECTOR set to {0, 129, 130 or 131} or TMT84 GSD file used or
IDENT_NUMBER_SELECTOR set to 1 and "CondensedStatus" parameter to OFF.
As per profile 3.02: TMT84 GSD file used or IDENT_NUMBER_SELECTOR set to 1 and "CondensedStatus" parameter to ON. If
IDENT_NUMBER_SELECTOR = 127, the GSD file used for establishing the cyclical data exchange determines whether diagnosis is according to profile 3.01
or profile 3.02.
Quality
Code
Measuring value
Limits
Quality Substatus
Quality
Status
Byte 5
Quality code (HEX) Quality status Quality substatus Limits
0x48
0x49
0x4A
UNCERTAIN Substitute set
OK
Low
High
Valid output value before error No valid output value before error
Quality
code (hex)
Quality
status
Quality
substatus
Limits
Quality
code (hex)
Quality
status
Quality
substatus
Limits
0x44
0x45
0x46
UNCERTAIN
Last usable
value
OK
Low
High
0x4C
0x4D
0x4E
UNCERTAIN Initial value
OK
Low
High
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