WIKA CTD9300 - Handbuch (Seite 55)

9037926 03/2005
55 WIKA Operating Instructions CTD 9300 Rev. 1
GB
Temperature Dry Well Calibrators CTD 9300
4. Operating the Calibrator
large temperature range of from 40 °C to 650 °C, the CTD 9300-
650 is a universally applicable allround calibrator that can be
adapted to various calibration requirements.
Irrespective of whether transducers are to be adjusted or
temperature sensors are to be calibrated on test benches, the CTD
9300-650 has been proven and tested in numerous calibration
tasks, in the laboratory, in the workshop and on site.
Calibrating Thermometers < 150 mm
If probes cannot be inserted down to the bottom of the adapting
sleeve due to insufficient sheath length, the heat dissipation error
produced can be considerably reduced by using an external
reference thermometer. For this purpose, an adapting sleeve with
two test bores is used.
The probe and the reference thermometer are inserted to the same
depth in the adapting sleeve. After switching to "t-extern", the
external reference thermometer will take on the measuring and
control tasks.
The minimum insertion depth of probe and reference should not
drop below 70 mm since the control system changes and the
stability gets worse when the reference thermometer is not
immersed deep enough. In addition, it will take longer until a stable
temperature is attained.
If probes are inserted to a depth less than 150 mm, the uncertainty
of measurement will increase during calibration. It is not possible to
make a general statement in this case, since with a low immersion
depth, factors such as:
„
Sheath diameter
„ Heat conductivity of the sheath material
„ Sensitive sensor length
„ Ambient temperature
considerably affect the uncertainty of measurement.
If short probes are to be calibrated frequently using the CTD 9300,
this fact can be considered individually on customer request when
adjusting and calibrating the CTD 9300, even in the measurement
uncertainty budget.