EZT-570S User Manual
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3.2.1.3
Dry Air Purge/Low RH Operation
The dry air purge event can provide two levels of operation.
Level 1 -
The first level of operation is dry air purge only. The purge only option consists of an air
dryer which dries a small volume of air and discharges the dry air within the chamber
work space. This helps reduce condensation on surfaces within the chamber by drying
the air. When this event is turned on with the purge only option, the air dryer will run
continuously until the event is turned off. Note that the chamber event must also be on in
order for purge to operate.
If the chamber is also equipped with the humidity option and the humidity system is
enabled, the purge system will be disabled automatically by the EZT-570S. The humidity
system cannot control the humidity level within the chamber if the purge system is
continuously trying to dry out the chamber. However, if the humidity set point is below
the minimum achievable humidity (low dewpoint limit), the EZT-570S will turn the dry air
purge back on in order to achieve the lowest possible humidity level.
Level 2 -
The second level of this option includes the frozen coil (low RH) option. This option
allows the chamber to reach a –29°C (-20°F) dewpoint. This relates to lower relative
humidity capabilities at a given air temperature. When the low RH option is installed and
the humidity system is enabled, the dry air purge system is automatically operated in
conjunction with the frozen coil by the EZT-570S controller based on the air temperature
and humidity set points. When required to obtain low humidity levels, the frozen coil and
dry air purge systems will start in order to achieve the target set point. When no longer
required, they will automatically turn off.
This level of operation also provides the benefit of being able to manually use the dry air
purge system by turning the purge event on and off. However, in the case where the low
RH option is installed, the humidity system must be disabled for the dry air purge to
function manually.
3.2.2
Special Chamber Options
Depending upon the type of chamber or installed options, there are several other events that may be
listed on the manual event screen. They will be used in conjunction with the optional equipment to
initiate or control the process related to that option.
3.2.2.1 Altitude
Operation
The altitude event turns the chamber’s altitude system components on and off. Altitude chambers are
specifically built to withstand atmospheric pressures. They have heavy gauge liners with additional
internal structure for reinforcement. They simulate altitude by utilizing a vacuum pump to draw air out
of the chamber and may also use compressed air to increase chamber pressure if altitudes below site
level are required.
The EZT-570S can provide a direct pressure reading in Torr (millimeters of mercury) or convert the
resultant pressure within the chamber into feet, which allows the altitude set point to be entered
directly in feet. The altitude system can operate independently of the chamber conditioning system;
thus, the chamber event does not have to be on for the altitude system to operate.
Chamber Temperature Control Limitations
Summary of Contents for EZT-570S
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