Proportional Gain; Integral; Derivative - MERRICK Genetix Safety, Installation, Operation And Maintenance Manual

setpoint and the process variable (i.e. Feedrate or Belt Speed). The PID algorithm
uses the deviation to calculate a new Belt Speed Demand to bring the feeder to
the setpoint.
A complete description of how PID control action works is beyond the scope of this
Manual, but a brief description of each term is provided below.

Proportional Gain

Integral

Derivative

Proportional Gain
The Proportional Gain (or sensitivity) is the closed loop gain, expressed in
percent (%). This setting affects all three PID components (Proportional,
Integral and Derivative). The higher the value of Proportional Gain, the harder
the controller will react to a deviation from setpoint.
Note: Proportional control by itself can result in stable control, but the feeder will
likely always be offset from the setpoint. Too much Gain and the control action
will oscillate. Too little Gain and the control action may be very slow to respond.
Integral
The PID Integral component uses the accumulated (integrated) deviation over
time to adjust the Belt Speed Demand signal. The Integral parameter,
expressed in units of s
place. The Integral function will, over time, make the deviation go to zero,
assuming everything else is in steady state. Essentially this means that the
longer time passes with the feeder not at setpoint, the larger the sum of the
deviation becomes over time, and the more control action that is applied to the
Belt Speed Demand signal.
The Integral function may be disabled by setting this parameter to zero, but this
is not recommended as it will usually result in very poor control, or a feeder that
never comes to setpoint.
Derivative
The PID Derivative component uses the rate of change (the trend) of the
deviation to adjust the Belt Speed Demand signal. The Derivative parameter,
expressed in seconds determines the sensitivity to trend changes. The
Derivative function will react earliest to deviations.
The Derivative function can be disabled by setting this parameter to zero, but
this is not recommended as it will usually result in poor control. However, only a
little Derivative action is typically required, so this setting is normally fairly low.
Note: The effects of all three of the above terms are combined to produce the
total change to the Belt Speed Demand signal. Thus, they all interact to some
degree. Settings for all three parameters will vary from feeder to feeder and will
also depend on the nature of your process.
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(i.e. 1/s) determines how fast the accumulation takes