Emerson E2 operation manual Pulse Accumulation, Alarms, Outputs

drop leg temperature rises above this setpoint, the con- denser fans are cycled ON regardless of the value of the TD.

The Drop Leg Offset setpoint is an adjustment entered, if needed, after measuring liquid subcooling during operation of an individual condensing unit.

The TD setpoint is the optimal difference between the refrigerant drop leg temperature and the ambient (plenum) temperature. When the TD (i.e., drop leg temp + drop leg offset - plenum temp) begins to climb above this setpoint, fans will be cycled ON to bring down the drop leg tem- perature, thus lowering the TD measurement.

The TD deadband setpoint is a range of values around the TD Setpoint within which the value of the TD calcula- tion is acceptable. When the TD rises above the setpoint plus 1/2 the deadband value, fans will begin cycling ON. When the TD falls below the setpoint minus 1/2 the dead- band value, fans will cycle OFF.

For the Condenser Fan On Delay setpoint, fans are cycled ON when the TD is above the setpoint at the rate set for Condenser Fan On Delay. For example, if this field is set to 30 seconds, each fan is staged ON in 30-second intervals until all fans are ON, or until the TD falls back below the setpoint.

For the Condenser Fan Off Delay setpoint, fans are cycled OFF when the TD is below the setpoint at the rate set for Condenser Fan Off Delay. In other words, if this field is set to 30 seconds, each fan is staged OFF in 30-sec- ond intervals until all fans are OFF, or until the TD rises back above the setpoint.

11.19.6 Inputs

The Drop Leg Temperature input is the current drop leg temperature used for TD control.

The Plenum Temperature input provides the current value of the ambient temperature used for TD calculation.

11.19.7 Alarms

For Drop Leg High alarm, the alarm setpoint is the drop leg temperature that, if exceeded, will cause an alarm to be generated. If you wish to generate an alarm for high drop leg temperature, enter the desired setpoint. Other- wise, to disable this alarm, leave the value set to NONE.

For Drop Leg Delay, if the drop leg alarming feature is used, enter the amount of time the drop leg temperature must be higher than the setpoint before an alarm will be generated (HHH:MM).

For TD High alarm, the TD alarm setpoint is the value of the TD calculation that, if exceeded, will cause an alarm to be generated. If you wish to generate an alarm for high TD, enter the desired setpoint. Otherwise, to disable this alarm, leave the value set to NONE.

For TD Delay, if the TD alarming feature is used, enter the amount of time the TD must be higher than the setpoint before an alarm will be generated (HHH:MM)

11.20 Pulse Accumulation

11.20.1 Overview

The Pulse Accumulation application counts incoming pulses and converts that consumption value into a rate value once per minute. Pulses are user-specified by the Input Type parameter (power, gas, liquid, or volume) to represent what is being measured.

The Pulse Accumulator input can support many types of pulse counting applications, such as flow meters for water and gas applications. In addition, application-spe- cific logging, such as hourly, daily and monthly usages are supported for pulse type inputs.

11.20.2 Configuration

Set the Input Type parameter to the desired measure- ment (power, gas, liquid, or volume).

NOTE: The engineering unit for the Pulse Accumulator Type Input is specified by the active EU parameter. This parameter is located

in the General Controller Information screen under the Engineering Units tab and determines what unit of measure will be used when the Input Type is set.

The analog input connected to the board and point

number must be configured as a Pulse Accumulator Type input. The engineering unit of the analog input must match the engineering unit that is being used in the Pulse Accu- mulation application.

TIP: The engineering unit that is active in the Pulse Accumulation application can be deter- mined by viewing the Total Accumulation out-

put on the application Status screen.

11.20.3 Outputs

All output information is available from the main Sta- tus screen or from under the Outputs tab in application Setup. Current output status, average output, high trip,

11-50 • E2 RX/BX/CX I&O Manual 026-1614 Rev 4 5-JAN-2013