Liebert RAC2-8 manual Key, Clear Alarms, Common Alarm-Inputs, Common Alarm-Output, Control Lockout

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Section 4: Glossary of Control Functions

If a zone includes more than 1 Standby unit, the same actions occur. At the end of each Interval, one unit is started and one is stopped. For example, if two Standby units are used, the First is started after the First Interval. The unit that had been running the longest becomes the Standby unit. After the second Interval, the second Standby unit is started, and the Running unit with the longest operating time becomes the Standby unit.

C key

The Clear key <C> at the local control panel serves two functions:

•Remove incorrectly entered data.

•Return to the previous display page.

Clear Alarms

All alarms are latching and must be manually cleared from the control panel or from a terminal. Be sure to review alarms before clearing them because recent alarm history is your best indication of system performance. When alarms are cleared, units that are running because of an Autochangeover will change back to their programmed status.

Common Alarm—Inputs

Each environmental control unit has a Common Alarm contact closure output. The RAC2-8 receives the Common Alarm from each unit as a control input. These alarms are annunciated only if the programmed Delays (Hold and/or Alarm) are exceeded. A Common Alarm from a Running unit causes a Standby unit to be turned ON, and turns OFF the Running unit if shutdown is selected. A Common Alarm from a Standby unit causes the unit to be unavailable.

Common Alarm—Output

A Form C contact labeled Common Alarm is available for customer use. This relay is energized during the following conditions:

•A Common Alarm input from one of the units

•A Temp/Hum Alarm

•Manual Override ALL ON internal switch

•Emergency Power Operation mode

•Emergency Power OFF

The Common Alarm is de-energized by the Silence pushbutton if DIP switch 1-7 is ON.

Control Lockout

A Form C contact labeled (optional) Control Lockout is available for customer use. This relay is energized during the following conditions:

•Manual Override internal switch (all units on)

•Emergency Power Operation mode

30 • User Manual (9/97)

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Contents $XWRð&KDQJHRYHUý&RQWUROOHU Table of Contents Table of Figures Unit RAC2-8Page Introduction Page Operation InstallationTo start up the RAC2-8 Page Glossary of Control Functions for more details OperationStatus Sub-menu Sequencing Status Screens cont’dUnits DelaySet Options Sub-menu cont’d Status Sub-menu cont’dSet Options Sub-menu Function Delays TEMP/HUM Standby PasswordAlarm Sub-menu DAY of Week Set Clock Sub-menuDate TimeUnit 01 Forced on Force OFF Restore Return LOG on TerminalStatus Screen Unit Status Setup Zones/Units OptionsSetup Zones/Units Options cont’d Number of ZONES/NUMBER of Units PER ZoneEmergency Power Units Unit Shutdown on Alarm08 0 no Set Clock Alarms Review and Alarms ClearUnit Labels Override a Unit Set Modem Options Set Modem Options cont’d Setup Temp/Humid OptionsSetup Temp/Humid Options cont’d Setup Standby Unit Options Set New Password Display SS Alarm BlockList of Alarms AlarmsAutochangeover Alarm AnnunciationAlarm Communications Alarm DelayAutosequencing Key Clear AlarmsCommon Alarm-Inputs Common Alarm-OutputHold Delay DelayEmergency Power OFF EPO Emergency Power OperationInterval Humidity AlarmsHumidity Lockout Inactive UnitOverride Normal TemperaturePassword Power Failure ModeRunning Units Restart DelayRestore Standby TestingTerminal Temperature AlarmsTemperature Sensitivity Temperature StagingZones Installation TB2 RAC2-8 Dimensional Enclosure Diagram RAC2-8 Component Arrangement RAC2-8 Connection Diagram RAC2-8 Switch and Jumper Settings
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