Quality Flags

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The quality flags (quality descriptor) provide additional information for the central station on the quality of an application object. The quality flags can be set/reset independent of each other from the PLC application via the F_iecSetAOQuality function. The F_iecGetAOQuality function can be used to interrogate the state of the quality flags. Any change in the quality flags leads to a spontaneous transfer of the data to the central station.

The following quality flags are internally analyzed by the substation at runtime:

• IECQ_BL_ON (blocked). If the process data of the application object were blocked for the transfer, mapping of the PLC and IEC process data is not executed for this application;

The following quality flags are internally set/reset by the substation at runtime:

• IECQ_IV_ON (Invalid). The substation sets the invalid flag if mapping of the PLC and IEC process data could not be carried out (e.g. due to faulty configuration of the application object). This behavior can be deactivated by setting group parameter IEC870_GRP_IV_OFF.

All other quality flags are sent to the central station without change.