Engineering manual - UniSAB III 1.10.8
001930 en 2021.06
261/346
7.5
Position transmitters for hydraulic slide systems (screw compressors)
The built-in capacity slide position transmitter and the Vi slide position transmitter must be adjusted cor-
rectly in the mechanical minimum and maximum position to ensure safe and reliable slide control. This
adjustment must always be carried out mechanically on the transmitter or by using software calibration
in UniSAB III if the transmitter cannot be calibrated. Furthermore, the slide speed must be adjusted to
avoid hunting. See also section
3.7 Compressor control - adjusting slide speed (screw compressors
.
To measure slide position the compressor is fitted with a position transmitter which yields 4-20 mA to
UniSAB III. A transmitter is always fitted at the capacity slide and one may be fitted at the volume ratio
slide if the compressor is made for automatic Vi regulation.
There are six types of position transmitters:
Fig. 27:
Turning transmitter
for SAB 110-128-163 and SAB 202 (capacity and Vi)
Fig. 28:
Long-stroke capacity rod transmitter
for SAB 110-128-163-202, SAB 81-89 and SAB 330 (capacity and Vi)
Fig. 29:
Long-stroke capacity rod transmitter
for SAB 283 Mk 1
Fig. 30:
Short-stroke capacity transmitter
for GST, GSV and RWF from Gram Refrigeration and
short-stroke volume transmitter
for GSV, RWF, SAB 283 Mk 1 and SAB 355 Mk 1
Fig. 31:
Long-stroke capacity rod transmitter
for SAB 193-233-283 and SAB 355.
Transmitter cannot be calibrated.
Fig. 32:
Short-stroke capacity transmitter
on SAB 120 and SAB 151.
Short-stroke volume transmitter
on SAB 193-233-283 and SAB 355. Transmitter cannot be calibrated.
1
3
No. 3
2
0%
2.
2.5
3.
4.5 4.
3.5
SPAN+ZERO
100%
3
2
1
ALU tube
3
2
1
ALU tube
Содержание SABROE Unisab III Control
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