7SR210 & 7SR220 Description of OperationUnrestricted ©2018 Siemens Protection Devices Limited Page 23 of 942.10 Virtual Input/OutputsThe relays have 16 virtual input/outputs, these are internal logic states. Virtual I/O is assigned in the same way asphysical Binary Inputs and Binary Outputs. Virtual I/O is mapped from within the INPUT CONFIG > INPUTMATRIX and OUTPUT CONFIG > OUTPUT MATRIX menus.The status of the virtual inputs and outputs is volatile i.e. not stored during power loss.2.11 Self MonitoringThe relay incorporates a number of self-monitoring features. Each of these features can initiate a controlled resetrecovery sequence.Supervision includes a power supply watchdog, code execution watchdog, memory checks by checksum andprocessor/ADC health checks. When all checks indicate the relay is operating correctly the ‘Protection Healthy’LED is illuminated.If an internal failure is detected, a message will be displayed. The relay will reset in an attempt to rectify thefailure. This will result in de-energisation of any binary output mapped to ‘protection healthy’ and flashing of theprotection healthy LED. If a successful reset is achieved by the relay the LED and output contact will revert backto normal operational mode, and the relay will restart, therefore ensuring the circuit is protected for the maximumtime.A Start-up Counter Meter is provided to display the number of start-ups the relay has performed. Once thenumber of start-ups has exceeded a set number, an Alarm output can be given.Figure 2.11-1 Start-up Counter MeterReset of the counter can be done from the meter or via a binary input or a command.Various types of start-up are monitored by the relay:1. power-on starts (auxiliary supply initiation)2. expected starts (user initiated via comms, language changes, custom protection curve etc.)3. unexpected starts (caused by the relay watchdog)Any combination of these can be selected for the start-up count. This is done in the MAINTENANCEMENU>START COUNT menu using the Start Up Types setting. All the start-up types selected will be added tothe overall start-up count.The number of restarts before the alarm output is raised is set in the MAINTENANCE MENU>START COUNTmenu using the Start Up Count Target setting.When the number of relay start-ups reaches the target value an output is raised, OUTPUT MATRIX>Start UpCount Alarm, which can be programmed to any combination of binary outputs, LED’s or virtual outputs.As a further safeguard, if the Relay performs a number of unexpected starts SYSTEM CONFIG>UnexpectedRestart Count in a given time SYSTEM CONFIG>Unexpected Restart Period, it can be configured using theSYSTEM CONFIG>Unexpected Restart Blocking setting to remove itself from service. In this case the Relaywill display a typical error message such as: -Figure 2.11-2 Start-up Counter Meter
