Eaton ELC-PB, Programming Manual

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3 . I n s t r u c t i o n S e t
M N050 03003E F or mo re infor ma tio n vi sit:
w w w. e a t o n . c o m
3-259
Device No. Function Set-point range Explanation
S
3
+13, 14:
Lower bound of integral
value, 32-bit
-2,147,483,648~
2,147,483,647
Ex: if
S
3
+9 is set as -1,000, the
integral value will be -1,000 when
it is smaller than -1,000 and the
integration will stop.
S
3
+15, 16:
Accumulated integral
value, 32-bit
Available range
of 32-bit floating
point
The accumulated integral value is
usually for reference. Users can
clear or modify it (in 32-bit floating
point) according to specific needs.
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.
10. The description of 32-bit
S
3
and 16-bit
S
3
are nearly 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 or K5:
y
In this control mode, the PID operation can be selected as Automatic, Forward, Reverse
or Automatic with MV upper/lower bound control modes. Forward / Reverse direction is
designated in
S
3
+4. Other relevant settings of the PID operation are set by the registers
designated in
S
3
~
S
3
+5.
y
PID equation for control mode k0~k2:
( ) ( ) ( )
S t PV K
S
t E K t E K MV
D I P
*
1
* *
+ + =
where
MV
: Output value
P
K :
Proprotional gain
( )
t E :
Error value
PV
(t) :
Present measured value
SV
(t) :
Target value
D
K
:
Derivative gain
( )
S t PV :
Derivative value of PV(t)
I
K
:
Integral gain