9.7
Limitation of individual sequences (SEQLIM)
9.7.1
Purpose and activation
The SEQLIM function provides limitation for individual sequences.
Purpose of SEQLIM
To activate this function, configure the SEQLIM input of the CTLOOP controller.
Where:
Activation
•
You can only assign analog inputs
•
You can only activate this function once per controller
•
If, at the same time, other influences act on the sequence controller, the priority
order according to subsection 9.1.4 “Function priorities” applies
9.7.2
Operating principle
This function is configurable either for minimum or maximum limitation. You can
assign its action to one of the sequences (Seq 1, Seq 2, … Seq 5):
General function
31
01
D
03
x
2
w
2
CTL1
1
y
max
x
1
w
1
Legend:
x
2
Limit controlled variable
w
2
Limit setpoint (min/max)
y
max
Limit signal, always acting as a closing signal
on 1 sequence (Seq1, Seq2…Seq5)
x
1
Main controlled variable
w
1
Main
setpoint
CTL1 Controller
1
(CTLOOP1)
If the controlled variable drops below the limit setpoint (SEQ SET), the limit function
with PI control (SEQ XP, SEQ TN) overrides the normal control function to maintain
the limit setpoint.
Minimum limitation
Minimum limitation causes the relevant sequence to close; the other sequences
are not affected.
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Siemens
Universal Controllers RLU2…
CE1P3101en
Building Technologies
Controller (CTLOOP x)
29.08.2008