Emerson E2 Manuel D’Utilisation

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.

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. 

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)

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.

Set the Input Type parameter to the desired measure-

ment (power, gas, liquid, or volume).

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.

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,