Danfoss VLT 6000 Manual page 14

parameter 413. A value of 16383 represents
the maximum feedback signal, as defined by
point 72 or parameter 414. See the VLT 6000
Operating In Istructions for details.
NOTE: NOTE: NOTE:
NOTE: NOTE:
If drive terminal 54 is programmed in para-
meter 311, Analog Inputs, for feedback,
any signal applied to terminal 54 is added to value
provided at point 73. Therefore, it is generally
advisable not to program parameter 311 for
feedback.
Example: Example:
Example: Example: In a cooling tower application, the feed- Example:
back signal comes from a temperature sensor with
a range of 40 o F to 140 o F. To unbundle bus feedback
2 (point 74) for the temperature sensor:
1. Set minimum feedback
(point 71 or parameter 413) to 40.
2. Set maximum feedback
(point 72 or parameter 414) 140.
3. Intercept = 40 (since the minimum feedback
value is 40)
4. Slope can be calculated as follows:
×
(Desired Range)
=
slope
Range of
− ×
(140 40) 0.1
=
16383
=
0.00061
Setpoint:
5 0 5 0 5 0 5 0 5 0 REF MIN REF MIN REF MIN REF MIN - The VLT 6000 can display the PID REF MIN
controller's setpoint and feedback signal in
units. The units displayed are chosen in drive
parameter 415. The value that the minimum
reference signal represents can be set using
either point 50 or drive parameter 204.
5 1 5 1 5 1 5 1 5 1 REF MIN REF MIN REF MIN REF MIN REF MIN - The VLT 6000 can display the PID
controller's setpoint and feedback signal in
units. The units displayed are chosen in drive
parameter 415. The value that the maximum
reference signal represents can be set using
either point 51 or drive parameter 205.
14
(Slope of Existing Point)
Existing Point
VLT ® 6000 HVAC
6 9 6 9 6 9 6 9 6 9 SETPOINT 1 SETPOINT 1 SETPOINT 1 SETPOINT 1 SETPOINT 1 - This is the PID controller's
setpoint, expressed in the units that were
chosen in parameter 415. It can be set to
any value between REF MIN (point 50 or
parameter 204) and REF MAX (point 51 or
parameter 205). If an attempt is made to set
point 69 to a value outside of this range, the
setpoint will not be changed. SETPOINT 1
can also be programmed using parameter
418, Setpoint 1.
7 0 7 0 7 0 SETPOINT 2 SETPOINT 2 - This PID controller setpoint is SETPOINT 2
7 0 7 0 SETPOINT 2 SETPOINT 2
used for applications where two feedback
signals will be compared to independent
setpoints. Refer to the VLT 6000 Operating
Instructions for more details.
SETPOINT 2 is expressed in the units
selected in parameter 415. It can be set to
any value between REF MIN (point 50 or
parameter 204) and REF MAX (point 51 or
parameter 205). If an attempt is made to
assign point 70 to a value outside of this
range, the setpoint will not change.
SETPOINT 2 can also be programmed
using parameter 419, Setpoint 2.
PID Controller Adjustments: PID Controller Adjustments: PID Controller Adjustments: PID Controller Adjustments: PID Controller Adjustments:
The following points adjust the operation of
the VLT 6000 PID control loop. They are
generally set during start-up and only
adjusted if changes in the system require it.
these values can also be set using
parameters.
See the VLT 6000 Operating Instructions for
more details.
6 1 6 1 PI ST PI ST AR AR T FREQ T FREQ
6 1 6 1 6 1 PI STAR PI ST PI ST AR ART FREQ T FREQ T FREQ (parameter 422) - This
sets the frequency to which the drivewill
accelerate after a start command. After it
reaches this frequency, the drive will
activate its PID controller. Point 61 can have
a value between the drive's minimum
frequency (as set in parameter 201) and its
maximum frequency (as set in parameter
202). If an attempt is made to set point 61 to
a value outside of this range, the
drive value will not change.
6 3 6 3 6 3 6 3 6 3 PI GAIN PI GAIN PI GAIN PI GAIN PI GAIN (parameter 423) - This sets the
value of proportional gain for the VLT 6000
PID controller. It can have a value between 0
and 10.
MG.60.G2.02 - VLT is a registered Danfoss Trademark