User Manual
Version 1.0 34
•
Vacuum Low Limit
: see Vacuum High Limit.
Figure 36
•
Vacuum Hysteresis
:
Vacuum Hysteresis
is used as the maximum allowable
overshoot of the chamber pressure when the chamber pressure is controlled by the
program via the vacuum valve. During each drying step, the range of the chamber
pressure is
between the current step’s target
Vacuum
- 5Pa and the target
Vacuum
+
Vacuum Hysteresis
. For example, if the current step has a target
Vacuum
of 100Pa
and a
Vacuum Hysteresis
of 20Pa, the actual chamber pressure will range from 95Pa
(100Pa
– 5Pa) to 120Pa (100Pa + 20Pa). If the chamber pressure exceeds the upper
limit, the program will open the valve, allowing the pump to suck air out and lowering
the pressure inside the chamber. If the chamber pressure drops below the lower limit,
the program will close the valve to stop the air flow.
Figure 37