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Pump down function
➨
Continuous pumping with pressure and time settings
• Operation on demand of a speed controlled NT VARIO / VARIO-B
pump
Preselections
+
Use the selection knob to select the parameters. All parameters can
be altered even while operation control is running.
+
Speed:
Preselection of the motor speed for pump down. The selec-
tion ”HI” effects the maximum speed and best ultimate vacuum of the
pump (with automatic speed reduction at ultimate vacuum).
The ”
Speed
” is adjustable in a range of 1-100% and to ”HI”.
+
Minimum:
The controller switches the pump off once the preset value
for ”
Minimum
” has been reached.
”
Minimum
” is adjustable in a range of 1-795 Torr (1-1060 mbar) or can
be set to ”Off”.
A preset ”
Duration
” (process time) has no effect if the process is
stopped due to a preset ”
Minimum
” before ”
Duration
” is reached.
+
Delay:
”
Delay
” determines the time the coolant valve remains open
after the process has been stopped.
The ”
Delay
” is adjustable in a range of 1-300 minutes or can be set to
”Off” (”Off” means that the coolant valve closes immediately when the
process stops.).
+
Duration:
”
Duration
” determines the total process time since control
start.
The process time is adjustable between 1-1440 minutes (24 h) or can
be set to ”Off”. ”Off” indicates that no endpoint for pump down is deter-
mined.
If a ”
Duration
” is preset, the controller switches off the pump when the
preset process time is reached, even if a preset ”
Minimum
” is still not
reached.
