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VLT Midi Drive FC-280P4K0
Руководство по программированию Страница: 68

Danfoss VLT Midi Drive FC-280P4K0 [68/136] Notice

4.8 Parameters: 7-** Controllers

7-00 Speed PID Feedback Source

Option: Function:

NOTICE

This parameter cannot be

changed while the motor is

running.

Select feedback source for speed CL

control.

[1] 24V encoder

[6] Analog Input 53

[7] Analog Input 54

[8] Frequency input 29

[9] Frequency input 33

[20] * None

7-02 Speed PID Proportional Gain

Range: Function:

0.015* [0 -

1 ]

Enter the speed controller proportional gain. The

proportional gain amplies the error (that is the

deviation between the feedback signal and the

setpoint). This parameter is used with

parameter 1-00 Conguration Mode [1] Speed closed

loop control. Quick control is obtained at high

amplication. However, if the amplication is too

high, the process may become unstable.

7-03 Speed PID Integral Time

Range: Function:

ms*

[2 -

20000

ms]

Enter the speed controller integral time, which

determines the time the internal PID control

takes to correct errors. The greater the error,

the more quickly the gain increases. The

integral time causes a delay of the signal and

therefore a dampening eect, and can be used

to eliminate steady-state speed error. Obtain

quick control through a short integral time,

though if the integral time is too short, the

process becomes unstable. An excessively long

integral time disables the integral action,

leading to major deviations from the required

reference, since the process regulator takes too

long to regulate errors. This parameter is used

with [1] Speed closed loop control set in

parameter 1-00 Conguration Mode.

7-04 Speed PID Dierentiation Time

Range: Function:

ms*

[0 -

200 ms]

Enter the speed controller dierentiation time.

The dierentiator does not react to constant

error. It provides gain proportional to the rate

of change of the speed feedback. The quicker

the error changes, the stronger the gain from

7-04 Speed PID Dierentiation Time

Range: Function:

the dierentiator. The gain is proportional with

the speed at which errors change. Setting this

parameter to 0 disables the dierentiator. This

parameter is used with parameter 1-00 Congu-

ration Mode [1] Speed closed loop control.

7-05 Speed PID Di. Gain Limit

Range: Function:

5* [1 -

20 ]

Set a limit for the gain provided by the dieren-

tiator. Since the dierential gain increases at higher

frequencies, limiting the gain may be useful. For

example, set up a pure D-link at low frequencies

and a constant D-link at higher frequencies. This

parameter is used with parameter 1-00 Conguration

Mode [1] Speed closed loop control.

7-06 Speed PID Lowpass Filter Time

Range: Function:

ms*

[1 -

6000

ms]

NOTICE

Severe ltering can be detrimental to

dynamic performance.

This parameter is used with

parameter 1-00 Conguration Mode [1]

Speed closed loop.

Set a time constant for the speed control low-pass

lter. The low-pass lter improves steady-state

performance and dampens oscillations on the

feedback signal. This parameter is useful if there is

a great amount of noise in the system, see

Illustration 4.15. For example, if a time constant (τ)

of 100 ms is programmed, the cuto frequency for

the low-pass lter is 1/0.1=10 RAD/s.,

corresponding to (10/2 x π)=1.6 Hz. The PID

regulator only regulates a feedback signal that

varies by a frequency of less than 1.6 Hz. If the

feedback signal varies by a higher frequency than

1.6 Hz, the PID regulator does not react.

Practical settings of parameter 7-06 Speed PID

Lowpass Filter Time taken from the number of

pulses per revolutions from encoder:

Encoder PPR Parameter 7-06 Speed

PID Lowpass Filter Time

512 10 ms

1024 5 ms

2048 2 ms

4096 1 ms

Parameter Descriptions

VLT

Midi Drive FC 280

Danfoss VLT Midi Drive FC-280P4K0 [68/136] Notice

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