LEESON Micro Series Compact Inverters - Manual (Page 77)

NOTE: If a reverse acting feedback device is being used, FB @ MIN should be set to the maximum process
variable value, and FB @ MAX should be set to the minimum process variable value .
77 P GAIN (PROPORTIONAL GAIN)
This parameter setting represents the speed command output (in % of maximum speed) that results from
each 1% of error (1% of the feedback range; FB @ MAX minus FB @ MIN).
Example: If P GAIN is programmed for 5%, and the error (difference between set point and feedback) is
10%, the speed command output of the Proportional term is 50% (10 x 5 = 50) of maximum speed.
78 I GAIN (INTEGRAL GAIN)
This parameter setting represents the ramp rate of the speed command output (in % of maximum speed per
second) that results from each 1% of error.
Example: If I GAIN is programmed for 0 .5 seconds, and the error is 5%, the rate of rise of the speed
command output of the Integral term is 2.5% (0.5 x 5 = 2.5) of maximum speed per second.
79 D GAIN (DIFFERENTIAL GAIN)
This parameter setting represents the speed command output (in % of maximum speed) that results from
each 1% per second change in the error .
Example: If D GAIN is programmed for 5 seconds, and the error is increasing at 2% per second, the speed
command output of the Differential term is 10% (5 x 2 = 10) of maximum speed.
NOTE: Differential gain is used as a “shock-absorber” to dampen overshoots in fast-acting systems.
However, it can be very sensitive to “noise” on the feedback signal and to digitizing errors, so it must be
used with caution .
80 PID ACC (PID ACCEL/DECEL)
This parameter sets the acceleration and deceleration rate of the set point reference into the PID unit . When
the set point changes, this function will “filter” the input to the PID unit by ramping the set point reference
from the previous value to the new value . This will help prevent overshoots that can occur when the PID
control attempts to respond to step changes in set point, resulting in smoother operation . If PID ACC is
set to 0 .0 seconds, it is effectively disabled .
81 MIN ALRM (PID MINIMUM ALARM)
This parameter setting represents the value that the feedback signal (in PID mode) or speed reference signal
(in open-loop speed mode) must fall below to activate the MIN ALARM output (see Parameters 52, 53,
and 54).
82 MAX ALRM (PID MAXIMUM ALARM)
This parameter setting represents the value that the feedback signal (in PID mode) or speed reference sig-
nal (in open-loop speed mode) must exceed to activate the MAX ALARM output (see Parameters 52, 53,
and 54).
NOTE 1: The MIN/MAX ALARM function can be used to start and stop the drive based on the level of
the speed reference signal or PID feedback signal. This is done by wiring a 2-wire start/stop circuit through
the drive’s Form C relay or opencollector output, and setting the Form C relay or open-collector output for
MIN/MAX (see Parameters 52, 53, and 54). When the signal drops below the MIN ALARM setting, the
75