Despatch RBC1-50 with Protocol Plus - Manual (Page 12)

8
THEORY OF OPERATION
Despatch RBC1-50 Burn-In ovens are made for the accelerated life testing of
microcircuit electronic devices to identify early mortality. The Despatch RBC1-50 ovens
are ideally suited for:
•
high-dissipation forward-bias burn-in,
•
high temperature reverse-bias burn-in,
•
stabilization baking of integrated circuits and other semiconductor devices.
Air atmosphere ovens recirculate air through the chamber. They can add heat and
remove dissipated heat. Air is taken from the burn-in room and circulated through the
oven. Heat is added by electric resistance elements, or removed through automatically
controlled exhaust.
Temperature Control
A modular microprocessor based digital temperature controller regulates the process.
The control utilizes a time-proportioning voltage signal to control heating, and a milliamp
signal to control cooling with minimal temperature fluctuations.
The controller temperature-sensing element, located in the air return plenum area,
senses the median air temperature of the oven. The controller automatically controls
heat dissipated by sending a signal to the automatic damper modulator. This automatic
damper controls the amount of fresh air drawn into the chamber, preventing excessive
cooling and conserving energy.
The high limit control protects the product and/or the oven from overheating. If the
product being processed has a critical high temperature limit, the high limit setpoint
should be set to a temperature somewhat below the temperature at which the product
could be damaged. If the product does not have a critical high temperature limit, the
high limit setpoint should be set 5 to 15 degrees higher than the maximum-programmed
setpoint at which the oven will operate. When the high limit trips, the alarm horn will
sound.
Please refer to the manufacturer’s manual on the control and high limit.