Teledyne Princeton Instruments NIRvana HS, Системное руководство

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Appendix E Troubleshooting 95
E.4 Cooling Troubleshooting
This section provides recommended troubleshooting guidelines for cooling-related
issues.
E.4.1 Temperature Lock Cannot be Achieved or Maintained
Possible causes for not being able to achieve or maintain lock include:
• Ambient temperature greater than +20°C. This condition affects TE-cooled
cameras. If ambient is greater than +20°C, you will need to cool the camera
environment or raise the set temperature.
• Airflow through the camera and/or circulator is obstructed. The camera needs
to have approximately 2 inches (50 mm) clearance around the vented covers. If
there is an enclosure involved, the enclosure needs to have unrestricted flow to
an open environment. The camera vents its heat out the side vents near the
nose. The air intake is at the rear of the camera.
• A hose may be kinked. Unkink the hose.
• Coolant level is low. Add coolant. Refer to Section E.3, External Coolant
Circulator: Low Coolant (Air in the Hoses) , on page 94, for additional
information.
• There may be air in the hoses. Add coolant. Refer to Section E.3, External
Coolant Circulator: Low Coolant (Air in the Hoses) , on page 94, for additional
information.
• The coolant circulator may not be working. If you do not hear the pump
running when the circulator is powered on, turn off the circulator and contact
the manufacturer’s Customer Support.
• The coolant circulator is positioned higher than the camera.
Reposition the circulator so that it is a minimum of 6 inches (15 cm) below, but
no more than 10 feet (3 m) below, the camera. Typically, the camera is placed at
table height and the circulator is on the floor.
• The target sensor temperature is not appropriate for the particular camera and
sensor.
• The camera's internal temperature may be too high, such as might occur if the
operating environment is particularly warm, if you are attempting to operate at
a temperature colder than the specified limit, or if you have turned off the fan
and are not circulating coolant through the camera. TE cameras are equipped
with a thermal-protection switch that shuts the cooler circuits down if the
internal temperature exceeds a preset limit. Typically, camera operation is
restored automatically in about ten minutes. Although the thermo-protection
switch will protect the camera, it is nevertheless advised to power down and
correct the operating conditions that caused the thermal-overload to occur.
E.4.2 Gradual Deterioration of Cooling Capability
Although unlikely with a NIRvana HS camera
1
, if a gradual deterioration of the cooling
capability is observed, it might due to damaged camera vacuum. This can affect
temperature performance such that it may be impossible to achieve temperature lock
at the lowest temperatures. It is highly desirable to maintain the system’s lowest
temperature performance because lower temperatures result in lower thermal noise
and better the signal-to-noise ratio. Contact the factory to make arrangements for
returning the camera to the support facility.
1.
Teledyne Princeton Instruments guarantees a permanent vacuum for the life of a NIRvana HS
camera.