Test and Measurement Forum

Pico Log Calibration Data for Thermocouples?!

Post any questions you may have about our current range of USB data loggers

Pico Log Calibration Data for Thermocouples?!

Postby allankey » Tue Apr 29, 2014 9:17 am

Hi, I am using the TC08 USB data logger. Please can you tell me where I can find the in-built calibration data that is used to determine the temperature? I am using a T-Type.

Thanks
allankey
Newbie
 
Posts: 0
Joined: Tue Apr 29, 2014 9:12 am

Re: Pico Log Calibration Data for Thermocouples?!

Postby Hitesh » Thu May 01, 2014 11:30 am

Hi allankey,

Are you looking for information in order to self-calibrate the device or apply some sort of scaling?

Have you referred to the following webpage?

http://www.picotech.com/applications/thermocouple.html

If you are looking to convert temperature readings in microvolts into temperature, the user manual for the RS-232 TC-08 states the following:

To convert a thermocouple reading, in microvolts, into temperature, you will need to
use a table containing microvolt readings at various temperatures for the type of
thermocouple that you wish to use. You can obtain these tables from the British
Standards Institute or thermocouple manufacturers.

First, take the cold junction temperature and use this table to convert it to microvolts.
Add this onto the microvolt reading from the thermocouple. Convert the total back to
temperature using this table.


Regards,
Hitesh

Technical Specialist
Pico Technology
Hitesh
Site Admin
Site Admin
 
Posts: 2009
Joined: Tue May 31, 2011 3:43 pm
Location: St. Neots, Cambridgeshire

Re: Pico Log Calibration Data for Thermocouples?!

Postby jerzydziewierz » Thu May 08, 2014 8:05 pm

So, just to make it completely clear,

Does USB TC-08 do the cold junction compensation when the mode is set to return the result in degrees centigrade, (when eg. using through the usbtc08.dll and user application),

or does the application has to do the calibration - by *unconverting* the temperature back to microvolts, substracting the cold junction voltage, and then converting back to degrees centigrade?

Regards,
jerzydziewierz
Newbie
 
Posts: 0
Joined: Thu May 08, 2014 7:27 pm

Re: Pico Log Calibration Data for Thermocouples?!

Postby Hitesh » Fri May 09, 2014 1:24 pm

Hi,

The previous post referred to the situation where scaling can be applied to the readings if required when using the PicoLog Recorder software.

When calling the API functions, the readings will be returned in degrees Celsius unless X is specified in which case it will be voltages.

If you are returning the values in degrees there is no need to convert the readings. You will need to enable the cold junction channel.

I hope this helps.
Hitesh

Technical Specialist
Pico Technology
Hitesh
Site Admin
Site Admin
 
Posts: 2009
Joined: Tue May 31, 2011 3:43 pm
Location: St. Neots, Cambridgeshire

Re: Pico Log Calibration Data for Thermocouples?!

Postby jerzydziewierz » Fri May 09, 2014 1:35 pm

Hitesh wrote:Hi,
If you are returning the values in degrees there is no need to convert the readings.
I hope this helps.


From this, should I understand, that as long as the cold junction channel is enabled, the temperature channels in the degrees centigrade mode are already being compensated?
jerzydziewierz
Newbie
 
Posts: 0
Joined: Thu May 08, 2014 7:27 pm

Re: Pico Log Calibration Data for Thermocouples?!

Postby Hitesh » Mon May 12, 2014 8:20 am

Hi,

The cold junction compensation will be applied regardless of whether the channel is 'enabled' in the API call. Cold junction compensation will not be applied if you are only measuring milliVolts.

Calling this function will allow you to view the cold junction temperatures if you wish to.

Hope this clarifies things.
Hitesh

Technical Specialist
Pico Technology
Hitesh
Site Admin
Site Admin
 
Posts: 2009
Joined: Tue May 31, 2011 3:43 pm
Location: St. Neots, Cambridgeshire

Re: Pico Log Calibration Data for Thermocouples?!

Postby jerzydziewierz » Mon May 12, 2014 9:43 am

It is now clear, thank you.
jerzydziewierz
Newbie
 
Posts: 0
Joined: Thu May 08, 2014 7:27 pm


Return to USB PC Data Loggers

Who is online

Users browsing this forum: No registered users and 1 guest