WIKA operating instructions, model CTH7000
EN
26
08/2020 EN/BG
4. Design and function
The currently selected sensor type is always shown at the top left of the measurement
screen (see the example shown in chapter 4.3.1 “Measurement mode”).
Channel A is always used for the PRT probe and channel B is always used for the
thermistor probe.
Use the
[Down]
key (twice) to select the thermistor probe on channel B. When the menu
is entered again, the thermistor line will be highlighted.
Selection of PRTs is more involved since the conversion method has to be set at the
same time as the probe is changed. Selecting one of the PRT menus will display the pass
code screen.
b. Conversion method
Use the [
Up]
and
[Down]
arrow keys to increment or decrement the pass code. Use the
[Enter]
key once the correct pass code has been set; this procedure helps to prevent
inadvertent changes. The default pass code setting is 4300.
⇒
The pass code can be changed using the settings menu; keep careful note of the new
value if changed. A lost password can be retrieved, but you will need to contact WIKA
directly for further information.
This screen will only appear once the correct pass code has been entered. This screen
shows that the CVD conversion method is currently selected. Use the
[Up]
and
[Down]
keys to highlight the required conversion method and then use the
[Enter]
key to select it.
For PRTs, the instrument provides three standard algorithms for converting resistance to
temperature. The choice of algorithm will depend on the type of PRT and its calibration.
■
DIN (1992) - used for un-calibrated industrial PRTs with 0.00385 ‘alpha’ value, to
provide a conversion of resistance to temperature in accordance with BS EN60751
(ITS 90) standard.
