Timer Description - Screw Compressors - Johnson Controls SABROE Unisab III Control Engineering Manual

6.5.11 Timer description - screw compressors

1. Start-start delay
States the number of seconds that must pass from one compressor start to the next. If the
compressor stops before the timer has counted down to 0, the timer will block restart.
1. For compressors configured with Rotatune=No, the timer can be set down to 600 sec-
onds
2. For compressors configured with Rotatune=Yes, the timer can be set down to 60 sec-
onds
2. Stop-start delay
States the number of seconds that must pass before the compressor can be restarted after
stop. This function is not used in Manual mode.
3. Start delay
When Unisab III is in Automatic or Remote, the compressor start will be delayed for the sta-
ted number of seconds.
4. Stop delay
When Unisab III is in Automatic or Remote and the compressor is below 5% slide stop posi-
tion, the timer will start counting down and stop the compressor at 0.
5. Suction ramp
This timer indicates how fast the compressor is allowed to lower its suction pressure 1°C. The
function is active as long as the compressor is working itself down to its normal working point.
When this has been reached, the compressor will be regulated according to the set regulating
values.
Used only in case of suction pressure regulation.
If the value is set at 0, this function is disabled.
6. Slide max.
At compressor stop the capacity slide will move towards minimum position. In case it fails to
get below 5% within the set time, an error message will be issued.
If Unisab III tries to move the slide during operation and the slide refuses to move within the
set time, an error message will appear.
7. Prelubrication
When starting compressors with prelubrication pumps, the prelubrication time is calculated
from the time when the oil float issues a signal.
1) For SAB 202, SAB Mk3 and VMY Mk3.
2) For SAB 163 Mk1.
3) For SV 10/20, FV 10/20, SAB 110 SR/LR, SAB 128 HR and SAB 163 HR.
4) For SAB 283 Mk1, SAB 355 Mk1, GSV, RWF and SAB 330 B. (B is short for Booster, which
can be selected in the Config. menu).
5) For SAB 330 HP. (HP means Booster = No).
6) For SAB 120→151, SAB 157HR, SABflex and SAB 193→355 prelubrication is not used.
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