Engineering manual - UniSAB III 1.10.8
262/346
001930 en 2021.06
Fig. 33:
Long-stroke capacity rod transmitter
for SAB 193 H-233 H-283 H-355 H.
7.5.1
Calibration procedure for position transmitters
The procedure for calibrating minimum and maximum position is the same for all transmitter types. In
the following, the procedure will be described for compressors with manual Vi, compressors with auto-
matic zero point and finally compressors with automatic Vi adjustment. Calibration of the specific trans-
mitter type is described in subsections 7.5.6 to 7.5.13. Software calibration is described in subsection
7.5.14
7.5.2
Capacity slide adjustment, manual Vi
Note:
The capacity transmitter must be adjusted every time the manual adjustable Vi position is
changed.
Start the compressor in
Manual
and make sure that the capacity slide is in minimum. Adjust the mini-
mum position on the transmitter. Now bring the capacity slide to its maximum position (i.e. when the cur-
rent consumption is no longer rising) and adjust the maximum position on the transmitter. Return the
slide to minimum and check.
To make sure that the slide is in maximum physical position (UniSAB III does not allow the capacity but-
ton to be activated after reaching 100% indication in the display) it is recommended to set
Cap. 100%
Adjustm
. at -10% after 100% calibration of the transmitter has been completed. See subsection 7.5.14
The slide indication in the display must now be 90%. If capacity can be increased further either automati-
cally by UniSAB III or by pressing the
/CAP. UP button, the slide has not yet been calibrated correctly.
(Note that it may be necessary to check if power consumption increases as it cannot be assumed that
the transmitter can supply more than 20 mA.) If capacity could be increased, cf. above, calibrate the
slide again from point 1 but keep -10% in
Cap. 100 Adj
.
Reset
Cap. 100 Adj
to what it was before calibration or adjust it until capacity shows 100%.
7.5.3
Capacity slide adjustment, auto zero point
For SAB 202 compressors with automatic zero point setting, there are two applicable methods to ensure
that the automatic zero point setting does not influence the adjusting of the transmitter minimum
position.
•
Do not adjust the minimum position on the transmitter until the compressor has stopped and the
slide is in mechanical zero.
•
Start the compressor in
Manual
and disconnect the automatic zero point setting while adjusting
the minimum position on the transmitter. Do this by setting
Manual zero = 0.1
in the picture
Set-
up/Configuration/Compressor block
.
Adjust the minimum position on the transmitter. Now bring the capacity slide to its maximum position (i.
e. when the current consumption is no longer rising) and adjust the maximum position on the transmitter.
Return the slide to minimum and check.
Remember to set
Manual zero = 0.0
as soon as the capacity slide adjustment is accomplished. It is im-
portant that the compressor only runs for a short period of time when the automatic zero point setting is
disconnected.
7.5.4
Capacity slide adjustment, auto Vi
To adjust the movement of the capacity slide, the Vi slide must be in minimum position. The Vi slide is
brought to minimum the following way: Start the compressor in
Manual
, select
Control/values/Capacity/
Vi slide position/Control
. The following picture will appear:
3
2
1
ALU tube
F2
Summary of Contents for SABROE Unisab III Control
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