Delta AH500 Manual page 170

AH 5 00 Mo d u le Ma n ua l
Control diagram:
T he instruction PID is inside the dotted line.
+
-
The PID algorithm is as follows.
t
( )
∫
= +
MV K E t K
P I
0
E
Forward action:
E
Reverse action:
b. Control mode
Cyclic control mode: Users set a cycle according to a controlled environment. (If the ambient
The width of a pulse is defined below.
 Pulse width=Output value (MV)/(Maximal output value–Minimal output value)×Cycle
Users can set the width of a pulse and a cycle (sampling time) by means of the instruction
GPWM.
Example:
The cycle is 2000 ms, the maximal output value is 100, and the minimal output value is 0. After
the PID algorithm is performed, the output value gotten is 50.
 Width of a pulse=50/(100-0)×2000 ms=1000 ms
Therefore, the pulse width used in the instruction GPWM is 1000 ms, and the cycle used in the
instruction GPWM is 2000 ms.
5 - 4 8
1/K
1/S
I
K
S
D
dE ) ( t
+
E ) ( t dt K *
D
dt
( ) ( ) ( )
=
t PV t - SV t
( ) ( ) ( )
=
t SV t - PV t
air temperature changes slowly, the cycle can be longer.)
+
+
1/K
G(s)
P
+