breaker status monitoring can be described using a module diagram. All the modules in thediagram are explained in the next sections.ContactpositionindicatorPOSCLOSEPOSOPEN52aCBOPENPhasecurrentcheckCBINVPOSI3PI_AI_BI_CGUID-60ADC120-4B5A-40D8-B1C5-475E4634214B-ANSI V1 ENFigure 266: Functional module diagram for monitoring circuit breaker status BLOCKand BLK_ALM inputsPhase current checkThis module compares the three phase currents with the setting AccDisLevel. If the currentin a phase exceeds the set level, information about phase is reported to the contact positionindicator module.Contact position indicatorThe circuit breaker status is open if the auxiliary input contact POSCLOSE is low, thePOSOPEN input is high and the current is zero. The circuit breaker is closed when thePOSOPEN input is low and the POSCLOSE input is high. The breaker is in theintermediate position if both the auxiliary contacts have the same value, that is, both arein the logical level "0" or "1", or if the auxiliary input contact POSCLOSE is low and thePOSOPEN input is high, but the current is not zero.The status of the breaker is indicated with the binary outputs CBOPEN, CBINVPOS and52a for open, error state and closed position respectively.14.17.7.2 Circuit breaker operation monitoringThe purpose of the circuit breaker operation monitoring subfunction is to indicate if thecircuit breaker has not been operated for a long time.The operation of the circuit breaker operation monitoring can be described by using amodule diagram. All the modules in the diagram are explained in the next sections.Section 14 1MRK 502 048-UUS AMonitoring608Technical manual
