Merlin Gerin Varlogic NR12, User Manual

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23
USER´S MANUAL
6. Miscellaneous
6.1 Stepping programs
The controller's algorithm will try to reach the target cos inside a tolerance area dependant
upon the C/K value. It reaches the value by switching on or off available relevant steps.
The regulation step program choice is as follows:
a) Stack Program (linear) :
All capacitor steps are of equal size (ex :1.1.1.1). The operation sequence obeys to a last-in-
first-out (LIFO) principle. The first step connected will be the last one to be disconnected and
vice versa. See Fig. 17
b) Normal program (2+ linear)
Normal program can be used on bank whose step ratio is 1.2.4.4.. The linear sequence starts
with the 3rd step. The two first steps are used as fine-tuning. The controller always start by
switching the first step then the second. Other steps are used successively See Fig. 18.
c) Circular A program
All capacitor steps are of equal size (ex :1.1.1.1). The operation sequence obeys the first-in-first-
out (FIFO) principle. The first step connected will be the first one to be disconnected and vice
versa. Then a circular sequence is followed. In order to operate correctly, the number of steps
programmed into the controller must strictly comply with the number of physical steps
See Fig. 19.
d) Circular B program (1+Circular)
Circular B program can be used on a bank whose step ratio is 1.2.2.2… The first step is used
as tuning after the activating limit is exceeded. The circular sequence starts with the 2nd step.
Figure 17: Stack program - Operation
sequence 1:1:1:1
Figure 18: Normal program - Operation
sequence 1:2:4:4
Step Step number
demand 1 2 3 4 5 6
+ X
+ X X
+ X X X
+ X X X X
+ X X X X X
+ X X X X X X
- X X X X X
- X X X X
- X X X
- X X
+ X X X
+ X X X X
+ X X X X X
- X X X X
- X X X
- X X
- X
Step Step number
demand 1 2 3 4 5 6
+ X
+ X X
+ X X X
+ X X X X
- X X X
- X X
+ X X X
+ X X X X
+ X X X X X
- X X X X
- X X X
- X X
- X