Magnetek GPD 315, Technical Manual

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5.28 PID Control
The Proportional, Integral and Derivative control function provides closed-loop control, or regulation,
of a system process variable (pressure, temperature, etc.). This regulation is accomplished by
comparing a feedback signal to a setpoint reference, which results in an error signal. The PID
control algorithm then performs calculations, based upon the PID parameter settings (n128 – n138,
n163
and n164), on this error signal. The result of the PID algorithm is then used as the new
frequency reference, or is added to the existing speed reference.
A. n128
: PID Control Selection Factory Setting: 0
Range: 0 to 8
Using this parameter, PID control can be enabled, and the type of PID control can be selected.
B. Setpoint Reference Selection
n004
: Reference Selection Factory Setting: 0
Range: 0 to 6
n024
thru n032: Multi-step Frequency Presets Factory Settings:
n032 = 6.0
all others = 0.0
Range (each): 0.0 to 400.0 Hz
The frequency reference becomes the PID setpoint.
C. Feedback Signal Selection
n164:
PID Feedback Selection Factory setting: 0
Range: 0 to 5
* Set SW2(2) to “I” (ON). SW2 consists of two separate slide switches and can be found just
above the upper row of control circuit terminals. The switch towards the bottom (labeled "2")
connects a 250
Ω
resistor from terminal FR to FC when set to the “I” (ON) position (to the right).
NOTE: All power must be removed from the GPD 315 before SW2 can be set. See Figure 1-1
for the location of SW2.
Setting Description
0
PID Disabled
1
PID Enabled (D = Feed forward)
2
PID Enabled (D = Feedback)
3
PID Enabled, Ref PID (D = Feed forward)
4
PID Enabled, Ref PID (D = Feedback)
5
Inverse PID Enabled (D = Feed forward)
6
Inverse PID Enabled (D = Feedback)
7
Inverse PID Enabled, Ref PID (D = Feed forward)
8
Inverse PID Enabled, Ref PID (D = Feedback)
Setting Description
0
Terminal FR (Voltage 0 – 10V)
1
Terminal FR (Current 4 – 20 mA)*
2
Terminal FR (Current 0 – 20 mA)*
3
Multi-Function Analog Input (0 – 10V)
4
Multi-Function Analog Input (Current 4 – 20mA)
5
Pulse Input