Pid Control - Hitachi L100 IP Series Instruction Manual

Function Display
f
Upper fre-
quency limit
A 61
Lower fre-
A 62
quency limit
0V
f
35
25
15
Acceleration 1
0Hz
Acceleration
Accel. 2
0,5Hz
15Hz
0,5Hz
Frequency
A 61
upper limit
Frequency
A 62
lower limit
1. jump frequency
A 63
1. jump frequency
A 64
width
2. jump frequency
A 65
2. jump frequency
A 66
width
3. jump frequency
A 67
3. jump frequency
A 68
width
Function Display
Introduction
The PID closed loop control has been designed with a control variable of "frequency in Hz" where the proportional
gain (k ), the integral gain (T
p
each other. The set value and the actual value are scaled in % (setting range 0–100%). For a better presentation of these
values they can be scaled and displayed in the desired physical engineering unit (e.g. flow or throughput of 0 to 30l/h).
The PID control output is limited to a lower limit of 0 Hz (or the frequency set under A 62 ) and to the frequency set
under A 04 (or A 61 , respectively) as an upper limit. This ensures that the motor running direction will not be reversed
when a negative deviation is present.
In order to optimize the PID control's behaviour it is advisable to keep acceleration and deceleration times as short as
possible.
Set value
Function A 01 is used to configure the method by which the set value is input and also the terminal where it is input:
Set value
Not in use
Function F 01
Multistage frequencies A 20 ... A 35
Analog input O (0–10V)
Analog input OI (4–20mA)
Actual value
For input of the actual value, one of the two analog inputs available (O or OI) can be used. The adjustment of the
actual value is done using functions A 11 through A 14 . (This adjustment of the actual value has already been
described as "set value adjustment" earlier in this manual. However, this description is only correct when the PID
) Function description / parameter setting range
*
Upper/lower limiter, jump frequency
The frequency range set by b 82 (start frequency) and A 04
(maximum frequency) can be further limited using functions A 61 and
A 62 (refer to the upper figure on the left). When a start command is
issued the inverter will output the frequency set under A 62 .
10V
In order to avoid resonances withhin the drive system three jump
frequencies can be configured using the functions A 63 through A 68 .
In the example (refer to the lower figure on the left) the first jump
t frequency (configurable using A 63 ) is positioned at 15Hz, the second
( A 65 ) at 25Hz, and the third ( A 67 ) at 35Hz. The jump frequency
widths (configurable using A 64 , A 66 , and A 68 ) were chosen to be
Jump width
1Hz each in the example.
1. jump
( A 64 )
Setting range 0.5Hz–360Hz.
N
(When 0.0 is entered, this function is not active).
Setting range 0.5Hz–360Hz
N
(When 0.0 is entered, this function is not active).
Setting range 0.1Hz–360Hz
N
(When 0.0 is entered, this function is not active).
Setting range 0.1Hz–10Hz
N
(When 0.0 is entered, this function is not active).
Setting range 0.1Hz–360Hz
N
(When 0.0 is entered, this function is not active).
Setting range 0.1Hz–10Hz
N
(When 0.0 is entered, this function is not active).
Setting range 0.1Hz–360Hz
N
(When 0.0 is entered, this function is not active).
Setting range 0.1Hz–10Hz
N
(When 0.0 is entered, this function is not active).
) Function description / parameter setting range
*

PID control

), and the differential gain (T
N
Parameter Scaling
00
(0–100%) * (parameter value of function A 75 )
02
- (0–100%) * (parameter value of function A 75 )
01 0–100% (independent of A 11 thru A 14 )
01 0–100% (independent of A 11 thru A 14 )
8-7
Chapter 8 – Using the digital operator
) of the control algorithm can be set independently from
V
( To be continued on next page )
Standard
setting
0.0
0.0
0.0
0.5
0.0
0.5
0.0
0.5
Standard
setting