SABROE UNISAB S-Control, Instruction Manual

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29
0171-761-EN
If several UNISAB S-Controls are coupled
together, please refer to the chapter
MULTI-
SAB sequential regulation of screw com-
pressors.
Important:
Please note that when automatic operation
is selected, the compressor will start and
stop automatically
.
Setting regulator parameters
UNISAB S-Control regulates the compress-
or capacity on the basis of the
suction pres-
sure
or the
brine temperature
.
To set the regulator set points:
· The LED in suction pressure ­ or brine
temperature ­ must be lit, as described
in the chapter entitled
Changing parame-
ters , before a set point can be set.
·
The suction pressure set point is dis-
played in
°
C
sat
and the set point for brine
temperature is displayed in ° C. The unit
is indicated by a LED.
By giving a set point for a regulator, the reg-
ulator in question will become active. If you
try to display the set point for the other (not
active) regulator the display will be off. The
set point of the active regulator is displayed
in the normal way.
When the required set point has been se-
lected, the other parameters in the regulator
can be set in the following way:
Use the LEDs beside
Control
ú
NZ
ú
P. Band
to access the following functions:
· Control is used to select the start sequen-
ce number and regulation system num-
ber.
The size of the field is as follows:
X X
- Y
where XX is the start sequence number
(0-14) and Y is the regulation system
number (1-14). Because only one Y-digit
is available, the numbers above 9 are dis-
played like this:
10 = A
11 = B
12 = C
13 = D
14 = E
If only one compressor is installed, these
figures are of no significance. However,
if two or more compressors are operating
together, please refer to the section en-
titled
MULTISAB sequential regulation
of screw compressors .
· NZ is the neutral zone which states the
extent to which the suction pressure or
brine temperature can fluctuate without
affecting the capacity of the compressor,
i.e. set point =
± 0.5 x NZ.
NZ only applies for the active regulator.
· P.Band is the proportional band, i.e. the
fault signal which is required to change
the capacity as quickly as possible (2
minutes to change the capacity 100%).
The capacity is changed as slowly as pos-
sible (20 minutes to change the capacity
100%) when the deviation is larger than
half the P. Band value. Please refer to the
following diagram and to the section en-
titled
Settings .
NZ and P.Band settings only affect the
active regulator. It is, therefore, possible