Johnson Controls SABROE Unisab III Control, Engineering Manual

Page: 86 / 348

Engineering manual - UniSAB III 1.10.8
86/346
001930 en 2021.06
Compressor control and surveillance
changes to 0. The “old” starting number is stored and reinserted if UniSAB III is configured differently
from
capacity set point control .
3.1.13 Climate compensation
This function can be used for both reciprocating and screw compressors without automatic Vi regulation.
The function is included in the picture
Setup/Compr.Control and is further described in chapter 6. Set-
up .
The inlet temperature set point on the water side of plants which are regulated by brine temperature or
hot water temperature can be controlled by the outside temperature. This requires a 4-20 mA tempera-
ture transducer, which is connected to the current inlet in UniSAB III as shown in the wiring diagrams in
the back of this manual.
Use a standard temperature transducer with a suitable temperature range, e.g. -30 - +25 ° C as shown in
Fig. 14. Note that the points of discontinuity in the diagram will be determined by the transducer measur-
ing range as seen in examples 1 and 2 below.
Fig. 14: Transducer measuring range
No further compensation will be made once the outside temperature is above the top point of discontinu-
ity and below the bottom point of discontinuity.
The factor by which the outside temperature should influence the inlet temperature positively or nega-
tively must be set in the
Brine , Hot water or User regulator.
In the picture Setup/Compr. Control , select Control on = Process out (brine) or Hot water , or (with User
regulator) Ext. Cool/Ext. Heat as well as Climate compensation = “Yes” in the picture Setup/Compr.
Control .
Example 1:
On a water cooling unit, the inlet temperature is to be corrected by the outside temperature.
• If the outside temperature is +30 ° C or more, the inlet temperature should be +4 ° C.
• If the outside temperature is +0 ° C or less, the inlet temperature should be +12 ° C.
In the menu Setup/Compr. Control , set Control on to Process out and Climate compensation on Yes . Se-
lect an outside sensor with a range of 0 - +30 ° C.
T inlet
Sp 1 (-5°C)
Sp 2
(+25°C)
4 mA
(-30°C)
20 mA
(+25°)
T
out