shelolab SM10HP-2 Скачать руководство пользователя страница 22

Страница: 22 / 44

22 |

P a g e

OPERATION (CONTINUED)

Heating

The operation of each SMOHP-2 oven is controlled by a JUMO dTRON digital controller, wired to a
solid state temperature probe located on the right wall of the oven chamber. The controller employs
proportional-integral-derivative analytical feedback-loop functions when measuring and controlling
the chamber air temperature. PID-controlled heating pulse intensities and lengths are proportional
to the difference between the measured chamber temperature and the current set point. The
frequency of pulses are 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.

The JUMO operates in one of two user-selected modes: The

heating profile mode

and

single set

point mode

. The heating profile mode allows the user to program and launch the heating profile,

but requires unlocking the current set point to adjust the temperature set point. The temperature set
point cannot be adjusted while a profile is running. The single set point mode unlocks the green
temperature set point on the home page. This allows the user to adjust the current set point at any
time with the arrow buttons, without unlocking the set point. However, this mode prevents the
launch of a profile and blocks access to the profile programing menu.

The lowest temperature the oven can achieve when powered is the room temperature (ambient)
+10°C.

The JUMO controller stores a

one heating profile

with

twenty four (24) programmable steps

Each step has three programmable parameter values

the

temperature set

point, the

time period

and an

option controller value

. The option controller value activates or deactivates an external

exhaust blower fan plugged into the external power outlet and mounted on the oven exhaust vent.
The external exhaust blower must be purchased separately. Please see the

Operation and

Programing JUMO dTRON Guide

for how to program a heating profile.

The heating rates given for the oven are for a 25°C environment. The ambient temperature of the
workspace around the oven affects heating and cooling rates.

Airflow and Applications

To achieve stated performance specs, the

oven intake and exhaust vents

must be fully closed

Operating the oven with the vents open impacts the oven chamber temperature uniformity and
stability. This may speed drying rates, depending on the nature of your samples or product.
Running the oven with an active power exhaust blower attached will reduce the oven chamber
temperature. The vents are intended to be open

after

completion of a heating profile or other

baking application to speed drying.

During normal operations an internal blower fan motor circulates air through the chamber and a
heating duct located above the chamber in a closed circuit. Heated air is routed into a duct that
makes up the right wall of the chamber. Air exits through small holes and blows horizontally across
the shelf space. This helps create temperature uniformity and enhances drying. The air then enters
a duct on the left side of the chamber through larger holes, and is pulled back up into the heating
duct above the oven chamber. If one or both vents are open, the rate of atmosphere exchange
between the chamber and surrounding workspace depends on several variable factors. These
include: ambient conditions, the volume of material in the oven chamber, and if an active power
exhaust unit is connected to the exhaust vent.