5-134 B90 Low Impedance Bus Differential System GE Multilin5.8 TESTING 5 SETTINGS5The TEST MODE FUNCTION setting can only be changed by a direct user command. Following a restart, power up, settingsupload, or firmware upgrade, the test mode will remain at the last programmed value. This allows a B90 that has beenplaced in isolated mode to remain isolated during testing and maintenance activities. On restart, the TEST MODE FORCINGsetting and the force contact input and force contact output settings all revert to their default states.5.8.2 FORCE CONTACT INPUTSPATH: SETTINGS TESTING FORCE CONTACT INPUTSThe relay digital inputs (contact inputs) could be pre-programmed to respond to the test mode in the following ways:• If set to “Disabled”, the input remains fully operational. It is controlled by the voltage across its input terminals and canbe turned on and off by external circuitry. This value should be selected if a given input must be operational during thetest. This includes, for example, an input initiating the test, or being a part of a user pre-programmed test sequence.• If set to “Open”, the input is forced to report as opened (Logic 0) for the entire duration of the test mode regardless ofthe voltage across the input terminals.• If set to “Closed”, the input is forced to report as closed (Logic 1) for the entire duration of the test mode regardless ofthe voltage across the input terminals.The force contact inputs feature provides a method of performing checks on the function of all contact inputs. Onceenabled, the relay is placed into test mode, allowing this feature to override the normal function of contact inputs. The TestMode LED will be on, indicating that the relay is in test mode. The state of each contact input may be programmed as “Dis-abled”, “Open”, or “Closed”. All contact input operations return to normal when all settings for this feature are disabled.Table 5–21: TEST MODE OPERATIONTEST MODEFUNCTIONTEST MODEFORCINGOPERANDIN-SERVICELEDTEST MODELEDCRITICALFAILRELAYINPUT AND OUTPUT BEHAVIORDisabled No effect Unaffected Off Unaffected Contact outputs and inputs are under normaloperation. Channel tests and PMU tests notoperational (where applicable).Isolated No effect Off On De-energizedContact outputs are disabled and contact inputsare operational. Channel tests and PMU testsare also operational (where applicable).Forcible On (logic 1) Off Flashing De-energizedContact inputs and outputs are controlled by theforce contact input and force contact outputfunctions. Channel tests and PMU tests areoperational (where applicable).Off (logic 0) Off Flashing De-energizedContact outputs and inputs are under normaloperation. Channel tests and PMU tests are alsooperational (where applicable). FORCE CONTACT INPUTSFORCE Cont Ip 1:DisabledRange: Disabled, Open, ClosedMESSAGE FORCE Cont Ip 2:DisabledRange: Disabled, Open, Closed↓MESSAGE FORCE Cont Ip xx:DisabledRange: Disabled, Open, Closed
