Danfoss VLT AQUA Drive FC 202 Operating Instructions Manual page 96

8. How to programme the frequency converter
20-81 PID Normal/Inverse Control
Option:
[0] * Normal
[1] Inverse
20-82 PID Start Speed [RPM]
Range:
0 RPM* [0 - par. 4-13 RPM]
8
20-93 PID Proportional Gain
Range:
0.50 N/A* [0.00 - 10.00 N/A]
20-94 PID Integral Time
Range:
20.00 s* [0.01 - 10000.00 s]
8.2.10. 22-** Miscellaneous
This group contains parameters used for monitoring water/ wastewater applications.
96
Function:
Normal [0] causes the frequency converter's output frequency to decrease when the feedback is
greater than the setpoint reference. This is common for pressure-controlled supply fan and pump
applications.
Inverse
[1] causes the frequency converter's output frequency to increase when the feedback is
greater than the setpoint reference.
Function:
When the frequency converter is first started, it initially ramps up to this output speed in Open Loop
Mode, following the active Ramp Up Time. When the output speed programmed here is reached,
the frequency converter will automatically switch to Closed Loop Mode and the PID Controller will
begin to function. This is useful in applications in which the driven load must first quickly accelerate
to a minimum speed when it is started.
NB!
This parameter will only be visible if par. 0-02 Motor
Function:
When the difference between the feedback and the setpoint reference is less than the value of this
parameter, the frequency converter's display will show "Run on Reference". This status can be
communicated externally by programming the function of a digital output for
Warning [8]. In addition, for serial communications, the On Reference status bit of the frequency
converter's Status Word will be high (1).
The On Reference Bandwidth is calculated as a percentage of the setpoint reference.
Function:
The integrator adds over time (integrates) the error between the feedback and the setpoint refer-
ence. This is required to ensure that the error approaches zero. Quick frequency converter speed
adjustment is obtained when this value is small. However, if too small of a value is used, the fre-
quency converter's output frequency may become unstable.
®
MG.20.M5.02 - VLT is a registered Danfoss trademark
®
VLT AQUA Drive
Operating Instructions
Speed Unit is set to [0], RPM.
Run on Reference/No