Parameter Group 21-** Extended Closed Loop; Introduction To Extended Closed Loop - Danfoss VLT Aqua Drive FC 202 Programming Manual

Programming Guide | VLT® Aqua Drive FC 202
Calculate the proportional band (error causing output to change from 0–100%) with this formula:
20-94 PID Integral Time
Default value: 8 s
Setup:
All setups
Data type: Uint32
The integrator accumulates a contribution to the output from the PID controller as long as there is a deviation between the reference/
setpoint and feedback signals. The contribution is proportional to the size of the deviation. This ensures that the deviation (error)
approaches zero. Quick response on any deviation is obtained when the integral time is set to a low value. Setting it too low, however,
may cause the control to become unstable. The value set is the time needed for the integrator to add the same contribution as the
proportional for a certain deviation. If the value is set to 10000, the controller acts as a pure proportional controller with a P-band based
on the value set in parameter 20-93 PID Proportional Gain. When no deviation is present, the output from the proportional controller is
0.
20-95 PID Differentiation Time
Default value: 0 s
Setup: All setups
Data type: Uint16
The differentiator monitors the rate of change of the feedback. If the feedback is changing quickly, it adjusts the output of the PID
controller to reduce the rate of change of the feedback. Quick PID controller response is obtained when this value is large. However,
if too large a value is used, the output frequency of the drive may become unstable. Differentiation time is useful in situations where
extremely fast drive response and precise speed control are required. It can be difficult to adjust this for proper system control.
Differentiation time is not commonly used in HVAC applications. Therefore, it is best to leave this parameter at 0 or OFF.
20-96 PID Diff. Gain Limit
Default value: 5
Setup: All setups
Data type:
Uint16
The differential function of a PID controller responds to the rate of change of the feedback. As a result, an abrupt change in the feedback
can cause the differential function to make a large change in the PID controller output. This parameter limits the maximum effect
that the PID controller differential function can produce. A smaller value reduces the maximum effect of the PID controller differential
function. This parameter is only active when parameter 20-95 PID Differentiation Time is not set to OFF (0 s).

Parameter Group 21-** Extended Closed Loop

5.20

Introduction to Extended Closed Loop

5.20.1
The FC 202 offers 3 extended closed-loop PID controllers in addition to the PID controller. These can be configured independently
to control either external actuators (valves, dampers, and so on) or be used with the internal PID controller to improve the dynamic
responses to setpoint changes or load disturbances.
462 | © 2024.06
Parameter type:
Conversion index:
Change during operation:
Parameter type:
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Change during operation:
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Parameter Descriptions
Range, 0.01 - 10000 s
-2
True
Range, 0=Off - 10 s
-2
True
Range, 1 - 50
-1
True
AU361182657213en-002101 / 130R0338