EXCEL CARE CONTROL ICONS244 74-5577–20 (US)EN2B-0184 GE51 R0611 (Europe)EXAMPLESThis chapter describes applications that combine multiple icons to perform a controlfunction. Applications are arranged alphabetically and include the following:Attenuator Use the MAT, SWI, and DIF control icons calculate a good approximation of a meanvalue, in this example, an outdoor air temperature.Average Value Calculation Use the SWI, MAT, CYC, and EVC icons to calculate an average outdoor airtemperature over three days.Floating Limits andAlarm Suppression Fixed alarm limits for some sensors, such as a supply air sensor, are notmeaningful, so it is useful to adapt the limits to a setpoint within an adjustableinterval. Also, it is often useful to suppress nuisance alarms. Use WIA, ADD, andDIF to float limits and suppress alarms.Operating Pump Switchover Use RIA, SWI, and MAT to switch pump operation between two pumps dependenton hours of operation.Optimized Start/Stop Calculate optimized values for starting and stopping air conditioning systems.Systems should start at the latest possible time and should stop as soon as possibleto save energy. This application uses the EOV, MAT, and SWI icons and may usethe ZEB icon to determine operating mode (heating or cooling).Positioning Signal Limitation Use the MIN and MAX icons to limit the range of the output value sent to apositioning signal.Setpoint Adjustments Use the SWI, DIF, and MAT control icons to control the setpoint of a actuatordepending on time of day.System Regulation This application regulates a partial air conditioning system with mixed air dampers,an air heater, and an air cooler. Setpoint management using the ZEB statementfollowed by PID controllers regulates this system. This application uses the SWI,ZEB, MAX, MIN, PID, and AVR icons.Trend Buffer Control In many cases, trend logs include points whose values change frequently. Over alengthy time interval, these frequent variations in signal exhaust the capacity of thetrend buffer. You can use CYC and SWI to control output to the trend buffer.Summary Table The following table cross-references the icons used in these applications.
