PID SYSTEMS OF INVERTER


PID control mode selection.

the operating method of inverter which adopts  pid control.
0: pid control is disabled.
1:pid control is enabled ; deviation signal is subject to derivative control.
2: pid control enabled ,feedback signal is subject to derivative control .
3 : pid control enabled (frequency command +pid output,deviation is subject to derivative control.
4: pid control enabled (frequency command + pid output,feedback is subject to derivative  control.

note : the pid control function is a control system that matches a feedback  value (i.e..a detected value) to the set targed value, combining proportional (p),integral (1),andderivative (d)control makes control possible even for a mechanical system with dead time.





PID CONTROL APPLICATION.

SPEED CONTROL take the mechanical speed signal as feedback signal.make the speed conform with target value..take the other mechanical speed signal as target value input, and actual speed as feedback signal to effect simultaneous control.
PRESSURE CONTROL.pressure signal is feedback signal , control pressure according to the set value.
FLOW CONTROL. control flow precision by taking flow signal as feedback signal.
TEMPERATURE CONTROL . temperature signal is the feedback ,the temperature is controlled by controlling the fan,s operations.
NOTE: the pid control function is a control system that matches a feedback value(i,e,,,.a detected value ) to the set target value . combining proportional (p), integral  (i), and derivative (d)control makes control possible even for a mechanical system with dead time . this action explains the pid control applications and operations,along with the constant settings and tuning procedure.



PID CONTROL ACTIONS.
in order to distinguish the separate pid control operations (i,e,,proportional, integral, and derivative), the following figure shows the changes in the control input ( i,e,the output frequency)when the deviation between the target value and the feedback are held constant..p control: control input proportional to the deviation is output. the deviation cannot be zeroed by p control alone, i control: a control input which is an integral of the deviation is output , this is effective for matching the feedback to the target value . sudden changes , however , be followed.
D CONTROL: a control input which is an integral of the deviation is output, quick response to sudden changes are possible.
PID CONTROL: optimum control is achieved by combining the best features of p, i, and d control.

TYPES OF PID CONTROL.
two types of pid control are possible with the inverter: measured_value derivation pid control and basic pid control .the types that is normally use is measured _value derivation pid control . with measured value derivative pid control . the feedback value is differentiated for pid control response is possible with respect to changes bot in target values and the control object.
 basic pid control : this is the basic form of pid control ,when the d control response is adjusted to follow changes in the control object , overshooting and undershooting can occur with changes in the target value . to enable pid control , make a setting between  1  to  4 (normally 2 or  4 is used for measured value derivative pid control ). when pid control is effective the target value can be selected as any of the following . if setting the target value input as  b1-01=0 (digital operator ),set the 01-03 to  , 1 , (% unit) and input a percentage value for the target value . (when the speed reference is changed ,100 % becomes the maximum frequency reference ).the input value from analog input terminal 3 is the pid target value .  input from multi function analog input terminal 16  (h 3 -05 = c ) or terminal 14 (h 3 - o 9 =c),when the input value of analog input terminal is the pid target value, it can be adjusted by setting the gain and basic of the analog .

PROPORTIONAL GAIN (P),
set the proportional gain of p control as multiples. the integral time of  I control is in unit of seconds.
NOTE:
the response of pid control is subject to proportional gain,integral time and different time. in the event of actual debugging , the response should be adjust when the load is operating to achieve the best operation state . 

INTEGRAL (1) LIMIT.
it is used to set the upper limit of control in unit of % with max . frequency taken as 100 %.
NOTE:
it is the  constant which limits the calculated value of integral control to be within a certain range in pid control . there is normally no need to change the default setting . reduce the setting if there is a risk of load damage , or of the motor going out of step , by inverters response when the load suddenly changes . if the setting is reduced too much , the target value and the feedback value will not match.

PID OFFSET ADJUSTMENT.

it is used to set the offset of pid control in unit of % with max.output frequency taken as 100%.
note:
it is content to adjust the pid control offset.if both the target value and the feedback value are set to zero,adjust the inverter's output frequency to zero.

 PID PRIMARY DELAY TIME CONSTANT:

content b5_08 is the low pass filter setting for pid control outputs.and it is in unit of second.
note:
please set the low pass filter time content of pid control output.there is no need to change the default setting normally.if the viscus friction of the mechanical system is high,or if the rigidity is low,causing the mechanical system to oscillate, increase te setting so that it is higher than the oscillation frequency period.this will decrease the responsiveness,but it will prevent the oscillation.

PID OUTPUT CHARACTERISTICS SELECTION.

the forward/reverse  characteristics selection of pid output 0: the forward operation characteristics of pid output  1:the reverse operation characteristics of pid output (output symbol is for reverse operation )

PID OUTPUT GAIN.

it is used to set the output gain of pid.
note :the contact to adjust the gain of pid control : setting range 0.0~25.0 frequency setting is 1.0

PID REVERSE  OUTPUT SELECTION :

it is the reverse operation selection of pid output. 0:executes 0 limit if pid output is negative  (dose not revers ). 1: reverse rotation if pid output is negative .
note : reverse operation will not act if revise prohibition is selected in   b 1-04 . setting range is 0~1
factory setting is 0 .

PID REVERSE OUTPUT SELECTION.

it is the reverse operation selection of pid output . 0: executes  0 limit if pid output is negative (dose not reverse ). 1:reverse rotation if pid output is negative .
note : reverse operation will not act if revise prohibition is selected in   b 1 -04 .

SELECTION OF PID FEEDBACK COMMAND LOSS DETECTION .

0:no detection of feedback loss . 1: pid feedback loss detection is available . to continue to operate after the detection ,but the abnormal contact will not act . 2: pid feedback command loss detection is available . to coast to stop after the detection and the abnormal contact will act .

PID FEEDBACK COMMAND LOSS DETECTION LEVEL.

it is used to set the pid feedback loss detection level in unit of %with max . output frequency taken as 100 % . setting range is 0~100, frequency setting is  0  . change during operation is  x  .
control methods .
v/f is a .
v/f with   p g  is a.
open loop vector  is  a.
flux vector is  a.

PID FEEDBACK COMMAND LOSS DETECTION TIME.

pid feedback loss detection time is to be set in unit  of second.

dwell frequency at start
dwell function is to maintain the output frequency at a certain value for a while the heavy load is started or stopped . to dwell the output frequency for some time can avoid stall out . the relations among these constants is as show in below.
b 6  - 0 3  dwell frequency at stop setting rang is 0,0~10,0 , frequency setting is 0.0
b 6 - 03 dwell frequency at stop setting range is 0.0~400.0. frequency setting is 0.0
b 6 - 04 dwell time at stop setting range is 0.0~10.0. frequency setting is 0.0

DROOP CONTROL GAIN.

set the slip as percentage of the slip at maximum frequency and rated torque .
note: slip (the slip at maximum output frequency and rated torque ). in unit of %.droop is disable when set as 0.0
b 7- 02  setting range is 0.0~100.0factory setting o.o..


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