Yaskawa MP900 Series Ladder Programming Manual - Manual (Page 227)

5.8 DDC Instructions
5.8.6 PID Control (PID)
5-158
[ b ] Parameter Table Configuration for PID Instruction with Real Numbers
∗ The relay input and output bit assignments are the same as for integers.
[ c ] Internal Operation of the Instruction
The deviation X input is used to calculate the PID compensation output as shown below.
In the formula shown below, X’ is the previous input value of X, Y’ is the previous I compensation, Ts is the scan time
set value, and Td* is the differential time.
∗ The differential time (Td) is Td1 when X – X’ and X’ have the same sign, and Td2 when X – X’ and X’ have dif-
ferent signs.
ΠWhen IRST (reset integration) is closed, the PID compensation is calculated with the I compensation set to 0.
P compensation = Upper/lower limit (UL or LL) of (Kp × X)
Yi (I compensation) = Upper/lower limit (IUL or ILL) of { (Ki × X + IREM) / + Yi’}
D compensation = Kd × (X – X’) × Upper/lower limit (IUL or ILL) of
Y (PID compensation) = Upper/lower limits (UL or LL) of P + I + D compensation values and dead zone A
(Width DB)
Address
Data
Type
Symbol Name Specification I/O
0 W RLY Relay I/O Relay inputs and relay outputs * IN/OUT
1 W – (Reserved.) Spare register IN
2 F Kp P gain Gain for the P compensation IN
4 F Ki I gain Gain for the input to the integral circuit IN
6 F Kd D gain Gain for the input to the differential circuit IN
8 F Ti Integral time Integral time (s) IN
10 F Td1
Differential time for
divergence
Differential time used when the input diverges (s) IN
12 F Td2
Differential time for
convergence
Differential time used when the input converges (s) IN
14 F IUL
Upper integration
limit
Upper limit for the I compensation IN
16 F ILL
Lower integration
limit
Lower limit for the I compensation IN
18 F UL PID upper limit Upper limit for the P + I + D compensation IN
20 F LL PID lower limit Lower limit for the P + I + D compensation IN
22 F DB PID output dead zone Dead zone width for the P + I + D compensation IN
24 F Y PID output PID compensation output (output to Out) OUT
26 F Yi I compensation I compensation storage OUT
28 F X Input value storage Storage of current input value OUT
Ti
Ts
Td
Ts