West Control Solutions SG 45 - Manual (Page 28)

6.10 Integrator function
The input signal can be totalized by means of a selectable integrator ( ConF \ Func \ Fnc.3 = 3).
Function:
Integrator with adjustable time constant ( PArA \ Func \ t.I) [specified in minutes] and adjustable input offset
( PArA \ Func \ P.I)
Formula:
y(t) = y(t-Tr) + Tr/t * (x +P.I)
y(t) = integrator output
y(t-Tr) = integrator output of the last cycle
Tr = cycle time (100ms INP1, 140ms INP1 + INP2)
t = time constant
x = integrator input
P.I = input offset (zero offset)
With a constant input value, the integrator output reaches the specified value after elapse of the adjusted time con -
stant t.I.
Reset:
Dependent on selection ( ConF\Logi\rES.I), the integrator can be reset via:
· Digital input di1
· Key combination Enter + increment key
(keep the Enter key pressed and actuate the increment key)
· Limit values Limit1 to Limit3
Example 1:
A flow in m
3
/h is measured. The integrator should measure the overall flow quantity. The measured flow is related to
time unit hours, i.e. time constant t.I = 1 hour = 60 min must be used. Parameter P.I can be used for zero correction.
Example 2: pulse output
The integrator is activated. The resulting process value is monitored using a limit value (without memory) , e.g. Lim1.
Lim.1 is defined as integrator reset function. Limit value Lim.1 is output e.g. on ouput 1 (OUT.1).
When exceeding limit value Lim1, there is a signal change at OUT1 during a period (50ms).
Functions
28 Integrator function SG 45
P.I
H.1
x
t (cycle)
Lim.1
Out.1