Introduction

OFS provides diagnostic data on connection status of the event sources and buffer level.

Items for Connection Diagnostic Between OFS and Devices

To diagnose the connection status with the time stamping event sources, 2 items of VT_I2 type (activated in a standard OPC group) are available and can be displayed on the SCADA (AVEVA Plant SCADA View for example):

  • #PLCQualStatus

  • #PLCQualStatus2

NOTE: Those 2 items have the same feature, but it is recommended to use #PLCQualStatus item because:

  • It optimizes the communication when used in groups with different periods.

  • It automatically uses #PLCQualStatus2 item on devices that are not the PLC.

Those items can return one of the following values:

QUAL_BAD + QUAL_COMM_FAILURE (value 0018 hex):

Device is INCONSISTENT (SymbolFile differs from PLC application).
QUAL_BAD + QUAL_DEVICE_FAILURE (value 000C hex):

No communication with the device since DEVICE_TO milliseconds.
QUAL_BAD (value 0000 hex):

Device is MISSING or UNKNOWN.
QUAL_GOOD (value 00C0 hex):

Communication with the device is correct.
QUAL_UNCERTAIN (value 0040 hex):

No communication with the device since less than DEVICE_TO milliseconds.

For more details on the time stamping event sources diagnostic items, syntax and content, refer to sections Specific Items and Time Stamped Events Configuration in OPC Factory Server User Manual.

Event Service Communication Diagnostic

Example of diagnostic information displayed in OFS: