Johnson Controls SABROE Unisab III Control Engineering Manual page 310

Version no. Description
1.1.0.1 For screw compressors a problem has been corrected. Setting the configura-
tion Pressure range to 25/59/25/25 did not work; it would incorrectly set the
range to 25/59/59/59.
For TSMC/TCMO reciprocating compressors, a problem has been corrected.
Setting the configuration Press/temp to kPa/°C did not work correctly for In-
termediate pressure. The Intermediate pressure in kPa was not converted cor-
rectly to °C/R. This problem concerned all refrigerants.
For HPO, CMO and TCMO reciprocating compressors, the text 'Filter Pressure'
has been removed from the main menu.
For the SAB HMI application, a problem has been corrected. After viewing the
Session/E-mail page, the application would show an error message when it
was closed.
1.1.0.2 A new small screw compressor type has been introduced - SABflex 159.
It is a frequency controlled screw compressor with an SSTV suction valve for
torque limitation.
It is now possible to set up Modbus RTU communication with Danfoss VSD
drive. Used for SABflex.
For SAB 120 to 355, the default oil filter diff. pressure settings have been
changed. The high alarm limit is lowered from 1.7 bar to 1.2 bar, and the high
shutdown limit from 2.0 bar to 1.5 bar.
The following Multisab situation involving a Rota screw and a standard screw
has now been corrected. In a situation where Multisab has calculated that the
Rota can take over, and the regulated process value is inside the lower P
band, the screw will regulate down in capacity to let the Rota take over. If
however, during the take over, the regulated process value gets inside the
neutral zone, the take over process will be stopped.
The following Multisab situation involving three or more Rota screws has now
been corrected. In a situation where more than two Rota screws are running,
the parallel stop capacity (of the last Rota) was not calculated correctly. Three
Rota compressors might in this situation run at 50% each, where the optimum
would be to have two Rota compressors running 75% each.
The function Capacity output AO1 now works for standard reciprocating com-
pressors too.
HPC compressors with a combination of High discharge alarm and the High
differential pressure limiter being active, would sometimes very quickly reduce
capacity from 75% to 50% and then stop. This problem has been corrected.
Engineering manual - Unisab III 1.10
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Troubleshooting
001930 en 2014.09