Delta DVP-SS2 - Page 419

DVP-ES2/EX2/EC5/SS2/SA2/SX2/SE&TP Operation Manual - Programming
3-298
Device No.
Function
Set-point range
Explanation
S
3
+17, 18 The previous PV, 32-bit
-2,147,483,648~
2,147,483,647
The previous PV is usually for
reference. Users can clear or
modify it according to specific
needs.
S
3
+19, 20
For system use only.
12. The explanation of 32-bit S
3
and 16-bit S
3
are almost the same. The difference is the capacity
of S
3
+5 ~ S
3
+20.
PID Equations:
1. When control mode (S
3
+4) is selected as K0, K1, K2 and K5:
 In this control mode, PID operation can be selected as Automatic, Forward, Reverse and
Automatic with MV upper/lower bound control modes. Forward / Reverse direction is
designated in S
3
+4. Other relevant settings of PID operation are set by the registers
designated in S
3
~
S
3
+5.
 PID equation for control mode k0~k2:
( ) ( )
( )
StPVK
S
tEKtEKMV
DIP
*
1
** ++=
where
MV
: Output value
P
K
: Proprotional gain
( )
tE
: Error value
PV
(t): Present measured value
SV
(t): Target value
D
K
: Derivative gain
( )
StPV
: Derivative value of PV(t)
I
K
: Integral gain
( )
S
tE
1
: Integral value of E(t)
 When
( )
tE
is smaller than 0 as the control mode is selected as forward or inverse,
( )
tE
will be regarded as “0"
Control mode
PID equation
Forward, automatic
E(t) = SV – PV
Inverse
E(t) = PV – SV
 Control diagram:
In diagram below, S is derivative operation, referring to “(PV﹣previous PV) ÷ sampling
time”. 1 / S is integral operation, referring to “previous integral value + (error value ×
sampling time)”. G(S) refers to the device being controlled.