Danfoss VLT FC 100 Series Programming Manual page 162

3. Parameter Description
20-74 Maximum Feedback Level
Range:
999999.000 User Units
par. 20-73 to 999999.999]
20-79 PID autotuning
3 Option:
*
Disabled
[0]
[1] Enabled
3.18.6. 20-8* Basic Settings
This parameter group is used to configure the basic operation of the frequency converter's PID Controller, including how it responds to a feedback that
is above or below the setpoint, the speed at which it first starts functioning, and when it will indicate that the system has reached the setpoint.
20-81 PID Normal/Inverse Control
Option:
* Normal
[0]
[1] Inverse
20-82 PID Start Speed [RPM]
Range:
*
0 [0 - 6000 RPM]
20-83 PID Start Speed [Hz]
Range:
*
0 Hz [0 - par. 4-14 Hz]
162
Function:
*
The maximum allowable feedback level should be entered here in User units as defined in par 20-12. If the level
[Value of
rises above par 20-74, autotuning is aborted and an error message will appear on the LCP.
Function:
This parameter starts the PID autotuning sequence. Once the autotuning has successfully completed and the
settings have been accepted or rejected by the user, by pressing [OK] or [Cancel] buttons on the LCP at the
end of tuning, this parameter is reset to [0] Disabled.
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. This is common for temperature-controlled cooling applications, such as cooling towers.
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 con-
verter 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 is set to [0], RPM.
Function:
When the frequency converter is first started, it initially ramps up to this output frequency in Open Loop Mode,
following the active Ramp Up Time. When the output frequency 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 is set to [1], Hz.
MG.11.C5.02 - VLT
®
VLT HVAC Drive Programming Guide
® is a registered Danfoss trademark