The information can, in addition to be viewed on the built in HMI, also be retrieved with the aidof a PC with PCM600 installed and by using the Event Monitoring Tool. The PC can either beconnected to the front port, or to the port at the back of the IED.19.3 Change lock CHNGLCK GUID-B48775D0-ACF0-49C6-A7F6-69AF37F1C68F v119.3.1 Application GUID-51EEC9C7-8ECF-4546-BC26-326861654340 v4Change lock function CHNGLCK is used to block further changes to the IED configuration oncethe commissioning is complete. The purpose is to make it impossible to perform inadvertentIED configuration and setting changes.However, when activated, CHNGLCK will still allow the following actions that does not involvereconfiguring of the IED:• Monitoring• Reading events• Resetting events• Reading disturbance data• Clear disturbances• Reset LEDs• Reset counters and other runtime component states• Control operations• Set system time• Enter and exit from test mode• Change of active setting groupThe binary input controlling the function is defined in ACT or SMT. The CHNGLCK function isconfigured using ACT.LOCK Binary input signal that will activate/deactivate the function, defined in ACT or SMT.GUID-8C333BC0-AA7A-4ED1-A772-18C22E8EEE62 v4When CHNGLCK has a logical one on its input, then all attempts to modify the IEDconfiguration and setting will be denied and the message "Error: Changes blocked" will bedisplayed on the local HMI; in PCM600 the message will be "Operation denied by activeChangeLock". The CHNGLCK function should be configured so that it is controlled by a signalfrom a binary input card. This guarantees that by setting that signal to a logical zero,CHNGLCK is deactivated. If any logic is included in the signal path to the CHNGLCK input, thatlogic must be designed so that it cannot permanently issue a logical one to the CHNGLCKinput. If such a situation would occur in spite of these precautions, then please contact thelocal ABB representative for remedial action.19.4 Denial of service DOS19.4.1 Application GUID-64F4D905-9F73-4073-B8F6-8D373155316A v4The denial of service functions (DOSFRNT, DOSLANAB and DOSLANCD) are designed to limitthe CPU load that can be produced by Ethernet network traffic on the IED. The communicationfacilities must not be allowed to compromise the primary functionality of the device. Allinbound network traffic will be quota controlled so that too heavy network loads can beSection 19 1MRK 505 363-UEN ASecurity336Application manual
