Engineering manual - UniSAB III 1.10.8
330/346
001930 en 2021.06
Version no.
Description
1.1.0.3
The service module introduced in version 1.0.9.0 has now been extended with a "Serv-
ice on Demand" function with condition based service intervals for both screw and re-
ciprocating compressors.
If the communication load on the Intranet/LAN, which UniSAB III is directly connected
to, is very high, the user interface may become very slow or in more extreme cases,
UniSAB III may restart. If this happens, you can lower the impact of the high communi-
cation load on UniSAB III by changing the parameter
LAN load high
to Yes.
The PMS output may remain ON (for ever) after compressor stop if the two PMS pa-
rameters,
PMS feedback fixed = No
and
PMS delay (49) = 0 sec
, are set as default.
This problem has been corrected.
Sometimes at compressor start-up, a pulse signal from the chiller flow evaporator
switch would not be suppressed by the
Flow evaporator
timer. This problem has been
corrected.
1.1.0.4
It is now possible to enable
Oil separator temperature control and supervision
for retro-
fit of the following screw compressor types: Gram, Stal, VMY and Grasso.
For most screw compressor types, it is now possible to choose both the normal low
pressure range 9/25/25/25 bar and the high-pressure range, 25/59/59/59 bar. The
high-pressure range, 25/59/25/25 bar, can also be selected for some compressor
types.
To make use of the high-pressure range 25/59/59/59 bar, i.e. when mounting a 25, 59,
59, 59 bar transmitter set, the max. pressure and temperature ranges have been ex-
tended for VMY Mk 2. Therefore, “VMY Mk 2” compressor types approved for high-
pressure use (e.g. CO
2
) can now use the high-pressure limits.
For the
Unload Assist
function for SAB 120-151 screw compressors, the max. limit for
the
CapacityDecreaseAssistRate
has been raised from 5% to 15% allowing the Vi slide
to push the capacity slide further down. The default settings remain unchanged (5)%.
For SAB193-355, the max. limit remain unchanged (5%).
For reciprocating compressors and VSD operation, the capacity step in/out is con-
trolled by the I or PID capacity regulator, following the set point signal. The
Delay Up
and
Delay Down
timers are not used. To make sure that the compressor cannot en-
gage the cylinders too fast, a ramp function has been added which will limit the maxi-
mum capacity change to 2.0%/sec. for step up and 3.0%/sec for step down, i.e. 50
seconds for 0 to 100% and 33 seconds for 100 to 0% Yield.
The
Liquid slugging
function known from screw compressors is now made available for
reciprocating compressors too. When the discharge temperature drops 5°K in 5 sec-
onds, an alarm is given, and when the temperature drops 10°K in 5 seconds, a shut-
down is given. When a capacity step is engaged, the liquid slugging alarm and
shutdown are disabled for 60 seconds to avoid false alarms. This is because the dis-
charge temperature will drop because of the increased capacity when a capacity step
is engaged.
For HPO and HPC heat pumps (R717), the default oil temperature limits are raised, i.e.
low alarm
to 45°C and
low shutdown
to 40°C.
Содержание SABROE Unisab III Control
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