The blocked functions will still be blocked next time entering the test mode, if theblockings were not reset.The blocking of a function concerns all output signals from the actual function, sono outputs will be activated.When a binary input is used to set the IED in test mode and aparameter, that requires restart of the application, is changed, theIED will re-enter test mode and all functions will be blocked, alsofunctions that were unblocked before the change. During the re-entering to test mode, all functions will be temporarily unblockedfor a short time, which might lead to unwanted operations. This isonly valid if the IED is put in TEST mode by a binary input, not bylocal HMI.The TESTMODE function block might be used to automatically block functionswhen a test handle is inserted in a test switch. A contact in the test switch (RTXP24contact 29-30) can supply a binary input which in turn is configured to theTESTMODE function block.Each of the protection functions includes the blocking from the TESTMODEfunction block.The functions can also be blocked from sending events over IEC 61850 station busto prevent filling station and SCADA databases with test events, for exampleduring a maintenance test.16.6 Change lock function CHNGLCK16.6.1 IdentificationFunction description IEC 61850identificationIEC 60617identificationANSI/IEEE C37.2device numberChange lock function CHNGLCK - -16.6.2 FunctionalityChange lock function (CHNGLCK) is used to block further changes to the IEDconfiguration and settings once the commissioning is complete. The purpose is toblock inadvertent IED configuration changes beyond a certain point in time.When CHNGLCK has a logical one on its input, then all attempts to modify theIED configuration will be denied and the message "Error: Changes blocked" willbe displayed on the local HMI; in PCM600 the message will be "Operation deniedby active ChangeLock". The CHNGLCK function should be configured so that it iscontrolled by a signal from a binary input card. This guarantees that by setting thatSection 16 1MRK 502 034-UEN -Basic IED functions500Technical Manual
