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1. Unisab III control

1.1. Introduction

The purpose of the Unisab III control system is to monitor, protect, control and regulate re-

ciprocating and screw compressors. The control cabinet as well as the electrical components

have been connected from factory. Thus, only a few connections are needed to link to the

electrical installations on site.

Unisab III is programmed according to the type of compressor it is going to control. See chap-

ter 6. Set-up in the Engineering manual.

Unisab III offers different ways of controlling/regulating compressor capacity according to

pressure levels or temperatures. Compressor capacity can be regulated both manually and

automatically.

Furthermore, a number of limiting functions have been incorporated. In periods of overloading

these limiting functions will intervene and limit compressor capacity until the situation has re-

turned to normal. Consequently, the number of undesirable operational stops will be reduced

as well as the need for supervision.

Compressors fitted with Unisab III Control can be linked via the built-in communication sys-

tem, Multisab. In this way compressors can work in a common refrigerating system, thus op-

timising the operation of the entire compressor plant.

The communication system further allows Unisab III to be connected to a PLC or PC central

monitoring, control and data logging system. Unisab III can be linked to and communicate

with former Sabroe control units such as Unisab II.

Unisab III is operated by means of a front panel as shown in Fig. 3. The front panel is well-

arranged with only a few keys and a distinct display.

Unisab III does not lose its preset or changed values in the event of a temporary power fail-

ure. It contains a battery which is used by the built-in timer to ensure that time and date are

always correct even if power has been disconnected. The hour counter and any stored alarm

values will maintain the correct time.

Unisab III control

Engineering manual - Unisab III 1.10

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Johnson Controls SABROE Unisab III Control User Manual

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