USB-2416

[Charles23]

Hello,

I have a datalogger (USB-2416 SN: 107817) that was recently checked for calibration by a third party (cirtificate attached).

S23100613310.pdf

I am encountering inconsistencies when collecting data sets with thermocouples. 

I am using Omega K-type thermocouples, and allowing the 45 minute warm up, with DAQami to collect. 

I have bundled the thermocouples together (without contact) with another datalogger's thermocouples(onset HOBO 4-channel thermocouple datalogger - this matches our EXTECH INSTRUMENTS EasyView 10 sensor). This was suspended in a sealed metal box with a heat lamp facing it (the temp increases)

This is an image of the temperature plotted over time. These datasets were collected at the same time in the same place. 

The temperature over time of the USB-2416 is not accurate. Even after switching the thermocouple types between the two loggers (the different types were accounted for in the software), the USB-2416 will fluctuate and not be correct. 

Any suggestions on how to troubleshoot or correct this issue? 

Thanks

 

 

[Fausto]

Hello @Charles23.

Please confirm if your temperature channel's data rate is set to 60 Hz.

Your USB-2416 device was recently calibrated as was the T&D TR-72WB (datasheet:  tr7wb-nw-spec.pdf) used to calibrate the USB-2416.  When were the ONSET HOBO 4-channel thermocouple datalogger (manual:  HOBO_4chan_thermo_logger_manual.pdf) and the EXTECH INSTRUMENTS EasyView 10 (datasheet: EXTECH_EA10_spec.pdf) devices calibrated?

Please elaborate on your comment "the USB-2416 will fluctuate and not be correct".  

Please describe your setup, i.e. fans, motors.  Where are the data loggers located with respect to the sealed metal box?

Regards,

Fausto

[Charles23]

Thanks Fausto,

 

No, The data rate has been set to 5 Hz for data collection. Should this not be the case?

 

I do not have calibration information on our other temperature measuring devices. But the Onset Hobo Logger and our EasyView 10 match temperatures. Also we have an an anemometer with a temp readout, and this matches the other two at ambient temperature (within tenths of a degree).

After one of four methods stick out, the thermocouples of our dataloggers were swapped and the issue remained with the USB-2416 datalogger and not the thermocouples themselves. 

 

My statement "the USB-2416 will fluctuate and not be correct". I am refering to the temperature seeming to decrease for a period of time before increasing to an incorrect final temperature. This is not what happens during this test, where heat is added to an area with uniform temperature. 

 

My procedure for the setup previously mentioned is as followes:

The test's intent is to compare relative insulative properties of many types of insulation and insulation applications. 

 

The room in wich the test is performed is insulated and has no active climate controll ( no fans, blowers, motors). Initial temp of the room for all trials is 73° F ± 2° F

The box is sealed with a lid using door seals and tape and thermocouples are suspended midway between the top and bottom of the box. 

 

Thank you,

     Charles

 

 

[Fausto]

Hello @Charles23.

Thank you for the additional information.

Using DAQami, what is your device's Main Firmware version?

 

The current firmware version is 2.03, which can be downloaded via the following link.

https://digilent.com/reference/daq-and-datalogging/firmware/start

If the ends of the thermocouples are exposed, please cover them with an epoxy or thin film tape and retest.  Please test with data rates at 5 Hz and 60 Hz. 

Would you have another USB-2416 onsite to test?

Regards,

Fausto

[Charles23]

The devices firmware is up to date at version 2.03 as shown below. 

The thermocouple ends are not exposed, here is a picture of them. 

After selecting different data rates in the software, the result is unchanged. The temperature reading still rises then decreases and is incorrect. The characteristic of the graph should match the one previously shown. 

 

Thanks again. 

[Fausto]

Hello @Charles23.

Thank you for the additional tests and images.

Please confirm each thermocouple is connected to the CH#H and CH#L terminals.  Connect a short wire between the CH#H and CH#L terminals of the unused channels.  Also, do not enable the unused channels in DAQami.

 

Where is the USB-2416 device located?  Please describe (or send an image of) its surroundings.

If the USB-2416 device's power supply is connected to the same electrical outlet as the heat lamp, please connect the USB-2416 to a different electrical outlet.

Regards,

Fausto

[Charles23]

I have resolved the problem, thanks for your help. 

 

In the thermocouple picture above, the thermocouple will plug into the connector leading to the datalogger. 

The cables were connected reversed inside the connector, but also at the logger. I believed that this was not a problem, but fixed it regardless. 

 

Below is an image of both dataloggers recording the same data again. 

 

Thank you again for your help.