Cascade Sciences CVO-2-HT, Installation And Operation Manual

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OPERATION
Heating Control
The oven temperature controller stores an user-selected constant temperature set point. When
powered, the oven heats the chamber shelves to the set point. The controller board is wired to a
solid-state temperature probe located in the chamber on the rear wall. When the controller detects
that the shelf temperature has dropped below the temperature set point, it pulses power to the
heating elements.
The controller employs proportional-integral-derivative analytical feedback-loop functions when
measuring and controlling the shelving temperature. PID-controlled heating pulse intensities and
lengths are proportional to the difference between the measured shelf temperature and the current
set point. The frequency of pulses is derived from the rate of change in that difference. The integral
function slows the rate of pulses when the temperature nears the set point to avoid overshooting.
TVO ovens rely on natural heat radiation for cooling. The oven can achieve a low-end operating
temperature of the ambient room temperature plus the oven waste heat.
High Limit Control System
The temperature controller contains a heating cutoff system with independent circuitry connected to a
redundant solid-state temperature sensor probe inside the oven chamber. This high limit system depowers
the oven heating elements whenever the chamber shelving temperature exceeds the current limit setting.
This safeguards the oven in the event of a failure of the main temperature control circuitry or main
temperature sensor probe.
The high limit is set by the end-user to a minimum of 10˚C above the highest temperature of the application
process the oven is currently being used for. Failure to set the high limit control system voids the oven
manufacturing defect warranty in the event of an overtemperature event.