Version no. Description
1.1.0.3 The service module introduced in version 1.0.9.0 has now been extended with
a "Service on Demand" function with condition based service intervals for both
screw and reciprocating 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 communication load on Unisab III by changing the pa-
rameter LAN load high to Yes.
The PMS output may remain ON (for ever) after compressor stop if the two
PMS parameters, 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 evapo-
rator switch would not be suppressed by the Flow evaporator timer. This prob-
lem has been corrected.
1.1.0.4 It is now possible to enable Oil separator temperature control and supervision
for retrofit of the following screw compressor types: Gram, Stal, VMY and
Grasso.
For most screw compressor types, it is now possible to choose both the nor-
mal 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 se-
lected 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 extended for VMY Mk2. Therefore, “VMY Mk2” compressor
types approved for high pressure use (e.g. CO
2
) can now use the high pres-
sure 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% al-
lowing the Vi slide to push the capacity slide further down. The default set-
tings remain unchanged (5)%. For SAB193-355, the max. limit remain un-
changed (5%).
For reciprocating compressors and VSD operation, the capacity step in/out is
controlled 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 engage the cylinders too fast, a ramp function has been
added which will limit the maximum 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.
Troubleshooting
Engineering manual - Unisab III 1.10
001930 en 2014.09
309/319
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