GE Industrial Solutions AF-600 FP Apogee_FLN - Manual (Page 14)

Network inputs to the frequency converter:
In addition to start/stop control, which was discussed in Strategy Two, the FLN provides the frequency converter with feedback and set-point information using
the following points.
Feedback:
69 BUS FB 1 A value of -163.83 % represents the minimum feedback signal. A value of +163.83 % represents the maximum feedback
signal. This should be the feedback used if only one feedback signal is supplied to the frequency converter.
NB!
If Drive terminal 53 is programmed by means of par. CL-00 Feedback 1 Source, for feedback, any signal applied to terminal 54 is added to value provided at
point 73. Therefore, it is generally advisable not to program par. CL-00 Feedback 1 Source for feedback.
Example:
In a cooling tower application, the feed-back signal comes from a temperature sensor with a range of 40 °F to 140 °F. To unbundle bus feedback 2 (point 74) for
the temperature sensor:
1. Set par. CL-13 Minimum Reference/Feedb. to 40.
2. Set par. CL-14 Maximum Reference/Feedb. to 140.
3. Intercept = 40 (since the minimum feedback value is 40)
4. Slope can be calculated as follows:
Slope = (Desired Range) × (Slope of Existing Point)
Range of Existing Point
= (140 − 40) × 0.1
16383
= 0.00061
Set-point:
66 SET-POINT 1 This is the PID controller’s set-point, expressed in the units that were chosen in par. CL-02 Feedback 1 Source Unit. It can be
set to any value between par. F-52 Minimum Reference and par. F-53 Maximum Reference. If an attempt is made to set
point 69 to a value outside of this range, the set-point will not be changed. SET-POINT 1 can also be programmed using
par. CL-21 Setpoint 1.
67 SET-POINT 2 This PID controller's set-point is used for applications, where multible feedback signals will be compared to independent
set-points. Refer to the AF-600 FP Design Guide for more details. SET-POINT 2 is expressed in the units selected in par.
F-53 Maximum Reference. If an attempt is made to assign point 70 to a value outside of this range, the set-point will not
change. Set-point 2 can also be programmed using par. CL-22 Setpoint 2.
PID Controller Adjustments:
The following points adjust the operation of the 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 AF-600 FP Programming Guide for more details.
61 PI START FREQ (par. CL-83 PID Start
Speed [Hz]) This sets the frequency to which the Drive will accelerate following a start command. After it reaches this fre-
quency, the frequency converter will activate its PID controller. Point 61 can have a value between the drive’s
minimum frequency (as set in par. F-16 Motor Speed Low Limit [Hz]) and its maximum frequency (as set in par.
F-17 Motor Speed High Limit [RPM]). If an attempt is made to set point 61 to a value outside of this range, the drive
value will not change.
63 PI GAIN (par. CL-93 PID Proportional
Gain) This sets the value of proportional gain for the PID controller. It can have a value between 0 and 10.
65 PI GAIN LIMIT (par. CL-96 PID Diff.
Gain Limit) This sets the maximum derivative gain for the PID controller. It can have a value between 5 and 50.
65 FB FUNCTION (par. CL-20 Feedback
Function) This sets how the PID controller responds to the Drive’s two feedback signals. Its value is an integer between 0
and 6. Refer to the AF-600 FPProgramming Guide for the list of choices and an explanation of each.
Network Outputs from the drive:
The points listed in Strategy One are commonly used.
AF-600 FP Apogee FLN Operating Instructions
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