GE B90 Instruction Manual

Also see for B90: Communications manual Communications guide Instruction manual Instruction manual Instruction manual

Contents

5-24 B90 LOW IMPEDANCE BUS DIFFERENTIAL SYSTEM – INSTRUCTION MANUALPRODUCT SETUP CHAPTER 5: SETTINGS5The language can be selected also for the front panel in EnerVista under Maintenance > Change Front Panel.FLASH MESSAGE TIME — Flash messages are status, warning, error, and information messages displayed in response tocertain key presses during settings programming. These messages override any normal messages. Use this setting tochange the duration of flash messages on the display.DEFAULT MESSAGE TIMEOUT — If the keypad is inactive for a period of time, the relay automatically reverts to a defaultmessage. The inactivity time is modified using this setting to ensure that messages remain on the screen long enoughduring programming or reading of actual values.DEFAULT MESSAGE INTENSITY — To extend phosphor life in the vacuum fluorescent display, the brightness can beattenuated during default message display. During keypad interrogation, the display always operates at full brightness.SCREEN SAVER FEATURE and SCREEN SAVER WAIT TIME — These settings are only visible if the B90 has a liquid crystal display(LCD) and control its backlighting. When the SCREEN SAVER FEATURE is “Enabled,” the LCD backlighting turns off after theDEFAULT MESSAGE TIMEOUT followed by the SCREEN SAVER WAIT TIME, provided that no keys have been pressed and notarget messages are active. When a keypress occurs or a target becomes active, the LCD backlighting turns on.CURRENT CUT-OFF LEVEL — This setting modifies the current cut-off threshold. Very low currents (1 to 2% of the rated value)are very susceptible to noise. Some customers prefer very low currents to display as zero, while others prefer the current todisplay even when the value reflects noise rather than the actual signal. The B90 applies a cut-off value to the magnitudesand angles of the measured currents. If the magnitude is below the cut-off level, it is substituted with zero. This applies tophase and ground current phasors as well as true RMS values and symmetrical components. The cut-off operation appliesto quantities used for metering, protection, and control, as well as those used by communications protocols. Note that thecut-off level for the sensitive ground input is 10 times lower that the CURRENT CUT-OFF LEVEL setting value. Raw currentsamples available via oscillography are not subject to cut-off.VOLTAGE CUT-OFF LEVEL — This setting modifies the voltage cut-off threshold. Very low secondary voltage measurements(at the fractional volt level) can be affected by noise. Some customers prefer these low voltages to be displayed as zero,while others prefer the voltage to be displayed even when the value reflects noise rather than the actual signal. The B90applies a cut-off value to the magnitudes and angles of the measured voltages. If the magnitude is below the cut-off level,it is substituted with zero. This operation applies to phase and auxiliary voltages, and symmetrical components. The cut-offoperation applies to quantities used for metering, protection, and control, as well as those used by communicationsprotocols. Raw samples of the voltages available via oscillography are not subject to cut-off.5.3.4 Clear relay recordsSETTINGS  PRODUCT SETUP  CLEAR RELAY RECORDSRESET UNAUTH ACCESS — Resets the access restriction counter.Selected records can be cleared from user-programmable conditions with FlexLogic operands. Assigning user-programmable pushbuttons to clear specific records is a typical application for these commands. Since the B90 respondsto rising edges of the configured FlexLogic operands, they must be asserted for at least 50 ms to take effect.Lower the VOLTAGE CUT-OFF LEVEL and CURRENT CUT-OFF LEVEL with care as the relay accepts lower signals as validmeasurements. Unless dictated otherwise by a specific application, the default settings of “0.02 pu” for CURRENTCUT-OFF LEVEL and “1.0 V” for VOLTAGE CUT-OFF LEVEL are recommended. CLEAR RELAY RECORDS  CLEAR USER REPORTS:OffRange: FlexLogic operand CLEAR EVENT RECORDS:OffRange: FlexLogic operand CLEAR OSCILLOGRAPHY:OffRange: FlexLogic operand RESET UNAUTH ACCESS:OffRange: FlexLogic operand CLEAR DIR I/O STATS:OffRange: FlexLogic operandVisible only for units with Direct I/O module