Johnson Controls SABROE Unisab III Control, Инструкция по эксплуатации

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Engineering manual - UniSAB III 1.10.8
001930 en 2021.06
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Compressor control and surveillance
For VSD controlled compressors, it will reduce capacity with up to 33% (i.e. speed or step) and the ramp
function for max speed/step down at 3%/sec will be active.
When the liquid level is low and back to normal, and after the Liquid level delay has timed out, the com-
pressor may increase capacity. In auto mode, it will allow an increase of capacity as requested by the
regulator. In manual mode, it will increase capacity to the same capacity as before the limiter became
active.
This function is enabled in Set up/Configuration/Plant/Liquid Level Lim. It is active when the compressor
is running.
This capacity limiting function for ChillPAC Mk 3 works for all reciprocating compressors, except old
SMC/TSMC/HPC compressors that are equipped with a differential pressure switch across the oil filter.
See also subsection
6.4.4 Plant, 20: Liquid level limiter.
3.6.9 Level control
The PID regulator can be set up for HP or LP liquid level regulation of an evaporator or a condenser.
A liquid level 4-20 mA transmitter measures the liquid level in the evaporator or condenser. The liquid
level range is 0 to 100%.
The PID regulator will control an analogue expansion valve in order to regulate the ammonia liquid level
according to the liquid set point. The output range is 0 to 100 %. The expansion valve is a motorised
valve. In series with this valve there is a solenoid stop valve which is active when the compressor is
running.
The PID regulator settings are made in the picture Control values/Process Temp/Evaporator level/Con-
trol . If the regulator is too fast or too slow you may adjust the Proportional band and/or the Integral time
values up or down accordingly.
LP: with this function the evaporator will be filled from the top. When the level rises above the SP setting
the valve must close.
HP: with this function the condenser will be drained from the bottom. When the level rises above the SP
setting the valve must open.
This function is enabled in Set up/Configuration/Plant/Level control . It is active when the compressor is
running.
3.6.10 DX control
The PID regulator can be set up for suction superheat regulation of the evaporator liquid filling. This
function is enabled in
Set up/Configuration/Plant/Level control . The DX regulation is only active when
the compressor is running.
Note: The UniSAB III DX function is released for freon and R717 refrigerants.