Binder vdl 115, Operating Manual

Page: 169 / 207

VDL (E3.1) 06/2020 Page 169/206
23. Reference measurements
23.1 Checking the temperature in the inner chamber
The controller display was adjusted in the factory to the temperature in the center of the usable volume
(chap. 28.1). The sensor probe of the reference measuring device was connected tightly to an expansion
rack positioned in the middle of the chamber.
23.1.1 Checking the controller display
•
Conduct the reference sensor into the inner chamber through the measuring port (12). The port must
be largely vacuum tight to enable a typical operation vacuum for the calibration. For a high vacuum,
use a measuring access port. Usually, a silicone plug with a hole for the sensor wire is sufficient.
•
Fix the sensor to the center of an expansion rack in the middle of the useable volume with adhesive
aluminum tape or thermal conductive paste to ensure sufficient thermal conductivity.
•
Perform the measurement in a thermally stable condition with 3 expansion racks and empty oven.
•
Equilibrating time: at least 12 hours.
23.1.2 Checking the spatial temperature exactitude
•
Fix at least 9 sensor probes on 3 racks with adhesive aluminum tape or thermal conductive paste to
ensure sufficient thermal conductivity
•
The distance of the sensor probes to all inner chamber walls must be at least 10% of the correspond-
ing inner chamber dimension (see DIN 12880:2007).
•
Perform the measurement in a thermally stable condition with 3 expansion racks and empty oven.
•
Response time: at least 12 hours.
Do NOT use the temperature probe of the reference measurement device without any contact
to the expansion rack, i.e., do NOT measure vacuum values!
In case the temperature probe is a thermo element, mount it so it is electrically insulated from
the rack.
If you note an excessive divergence between the controller and reference temperatures, please contact
BINDER Service to calibrate the temperature controller.