Calibration of temp probe when using VTN-2 ( Temperature & Humidity Sensor Extension)

[rattters]

According to the info on this product the temp sensor calibration will need adjusting.

Note calibration will need to be adjusted on the profilux unit when using this cable.

Question is how or where is this done?

Thanks

Edit, its a PIII if it makes any difference

[rattters]

Ok, found this in the programming guide

If the cable to the temperature sensor is extended (or made shorter through removing an extension) then ProfiLux has
to compensate the measurement error caused by the change of the cable length. A change of the cable without
compensation can have a significant measurement deviation as a consequence.
In order that ProfiLux can calculate the compensation correctly, you have to proceed as follows:
The sensor has to be connected and has to be inside the water (and has to remain there also during this process

without the extension connected?

– the water should not vary a lot concerning the temperature during the next minutes).
Select this menu (Temperature->Extension).
Wait for the given time.

Which is?

Change the extension cable (add resp. remove), confirm with RETURN.

This bit confuses me, change the extension, should that be fit the extension?

add resp??

Now ProfiLux calculates the compensation values, afterwards you can store these values. From now on ProfiLux
displays the correct (compensated) temperature value.

Please explain the above comments in red, thanks.

[Wirus]

without the extension connected?

Yes

Which is?

It´s shown in display of PL3; up to 999 seconds

This bit confuses me, change the extension, should that be fit the extension?

Visualize what you are doing:

• You put the probe into a tank with stable temperature
• Now you start cable compensation process
• PL3 will measure temperature for a little while to ensure it´s stable
• You change cable (add or remove extension); probe still remains in the tank
• PL3 measures temperature for another little while to ensure it´s still stable
• Now calibration process uses the measured difference between before and after to adapt calibration data to have same temperature as at start of process

two additional comments:

• Don´t try to calibrate/adjust temperature if you don´t have an extension cable - it´s normally not necessary and not recommended.
• You always can get back factory calibration data if you have done anything silly (but it´s possible only at PL3, not via PC software PLC

[rattters]

Thank you for explaining that, I am moving my PIII tomorrow and I need to use the extension cable so wanted to understand the process, thanks again.

[rattters]

Visualize what you are doing:

• You put the probe into a tank with stable temperature
• Now you start cable compensation process
• PL3 will measure temperature for a little while to ensure it´s stable
• You change cable (add or remove extension); probe still remains in the tank
• PL3 measures temperature for another little while to ensure it´s still stable
• Now calibration process uses the measured difference between before and after to adapt calibration data to have same temperature as at start of process

Ok, I did this as above and with the extension lead in place the temp reads about 2 degrees lower than it should, I tried it a few times and still get the same result.

If I just put the lead in place without doing the extension setting, then the temp reads about 0.3 lower.

Any ideas?

Thanks

[rattters]

Still need help on this one guys, thanks.

[Matthias]

obviously something went wrong, maybe you performed this procedure several times

-> undo it and start again:
- execute "calibrate" for this temp sensor - this will restore the original calibration
- then do the process again