APC IN ROW RD ACRD101 - Manual (Page 28)

InRow RD 10 kW Air Cooled Operation and Maintenance 20
PID settings
Path: Main > Set Group PID
The Proportional plus Integral plus Derivative (PID) loop controls the output of the fans.
Caution: This procedure is to be performed by APC authorized personnel only. Improperly
set PID controls could result in equipment damage.
There are two sets of PID coefficients stored in the unit. One set is used when the unit is programmed for
Spot (Proportional) mode and the other set is used when the cooling unit is programmed for InRow
mode. Only one set can be active at a time. The active PID set is determined by the value of the Type and
Capacity Ctrl properties (Path: Main > Configure Group). The active set can be read, written or set to
default.
Gain (P). The proportional multiplier (gain) for this mode or actuator. The proportional multiplier
adjusts for the difference (error) between the measured value and the setpoint.
Rate (I). The integral multiplier (reset rate) for this mode or actuator. The integral multiplier adjusts for
error measurement and the amount of time that the error has existed. The integral multiplier adds to or
subtracts from the output in small increments to correct for the offset error caused by the proportional
contribution.
Deriv (D). The derivative multiplier (derivative) for this mode or actuator. The derivative multiplier
adjusts the output for rapid changes in the error, correcting for the rate of change of the error over time.
Reset to Deflts (InRow or Spot (Proportional) only) . The Gain, Rate and Derivative coefficients
return to their default values.