Delta AS Series Programming Manual page 491

AS Ser ies Pro gra mm in g M anu al
Example 2: Tuning the parameters used with the PID instruction
Suppose that the transfer function of the plant is the first-order function
10 milliseconds. It is suggested that you follow these steps when tuning the parameters.
Step 1: First, set the K
and the process values. The results are shown in the following diagram.
Step 2: When the K
no overreaction. However, due to the fast start-up, the transient output value (MV) is big. Neither 40 nor 20 is a
suitable value. When the K
is too slow. Therefore, K
Step 3: After setting K
than K . Then, increase K
P
than ten percent of K
_6
Note: This example is only for reference. You must tune the parameters properly according to the actual condition of the
control system.
6 - 2 1 2
and the K to 0. Next, set the K
I D
1.5
K =40
P
K =20
P
1
0.5
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
is 40, there is overreaction. When the K
P
is 10, the reaction curve of PV approaches SV smoothly. When K
P
= 10 is the best choice.
P
to 10, increase K . For example, K
P I
. For example, successively set K
D
. Finally, the relation between PV and SV is shown in the following diagram.
P
1 .5
1
0 .5
K =10,K = 8,K =0.2
P
0 0 .1 0 .2 0 .3
( )
G s =
to 5, 10, 20 and 40 successively, and record the target values
P
SV= 1
K =10
P
K =5
P
is 20, the reaction curve of PV is close to SV, and there is
P
is successively set to 1, 2, 4, and 8. K
I
to 0.01, 0.05, 0.1, and 0.2. K
D
PV= SV
I D
0 .4 0 .5 0 .6 0 .7 0 .8 0 .9
b
, the SV is 1, the sampling time Ts is
s + a
1 T ime (s ec)
is 5, the reaction
P
should not be larger
I
should not be larger
D
T ime (s ec)
1