4. Configuration
55
MODBUS Internal Quality
As the MODBUS standard don’t specify quality types to each point, but for help on use of each
point's communication diagnostic, MasterTool allows the quality variables mapping, through an
internal own structure, to each MODBUS point. The Table 4-13 describes the quality types that each
MODBUS point can assume.
Initial value. The point was never updated.
Communication OK. The point is updated.
FLAG_COMM_FAIL AND FLAG_RESTART
Communication error. The point never
was updated.
FLAG_COMM_FAIL AND FLAG_OLD_DATA
An error has occurred but the point was
updated and now has an old value.
FLAG_FAILURE AND FLAG_RESTART
It has received an exception response and
the point kept its initial value.
FLAG_FAILURE AND FLAG_OLD_DATA
It has received an exception response, but
the point has a valid old value.
FLAG_RESTART AND FLAG_OLD_DATA
Device stoped. The point has an old
value.
Table 4-13. MODBUS Quality
Local Bus I/O Modules Quality
To help in the use of each I/O point's diagnostic, MasterTool automatically creates a quality structure
to each local bus module used on the PLC project, through an own internal structure accessible by
structureQUALITY, available in GVL IOQualities.
The Table 4-14 describes the quality types to each input and output point.
For futher information look at GVL IOQualities.
The quality has this value before have
been read or written for the first time.
Communication OK. The point is updated.
FLAG_OLD_DATA AND
FLAG_FAILURE
Non operational module. However, the
data have been read or written at least
once.
bOverRange OR
bUnderRange
The value is above or below the module's
input allowed range.
bInputNotEnable OR
bOutputNotEnable
Open loop in input module.
External power supply is under
operational minimum limit.
bShortCircuit OR
bOutputShortCircuit
Cold junction sensor error
Table 4-14. I/O Modules Quality
PROFIBUS I/O Modules Quality
Different from local bus, MasterTool don’t automatically create the PROFIBUS modules quality
structures, and neither the PLC update such structures. Therefore the creation and cyclic update of
PROFIBUS modules quality is user resposability.
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General