Temperature logging alongside VDC and other readings - methodology - Page 1
Forum section: electronics / general

author: Rax
author_rank: Super Contributor
timestamp: November 18, 2023, 06:09:02 pm
content: As I gained capacity to log readings off of my Prema 6048 meter, I'm looking for attaching temperature readings alongside that. Time would also be nice, but maybe that's just a bit of Python code I need to add to the script.My bench thermometer - not a precision unit, but collects temperature, humidity, etc. - has Bluetooth, so maybe getting its own logs communicated in some way over BT with the bench computer can be achieved. I haven't been able to get that going yet, but it's a potential option.But was curious what solutions have others adopted. I am not positive on this, but I don't think the Prema can read VDC and T at the same time (though it's able to read T, just not at the same time with VDC, as far as I can tell).

author: Alex Nikitin
author_rank: Super Contributor
timestamp: November 18, 2023, 07:03:19 pm
content: Here is my solution, a bit over the top for most things though.CheersAlex

author: alm
author_rank: Super Contributor
timestamp: November 18, 2023, 10:21:03 pm
content: I'm using a combination of a BME280 attached via I2C to a BeagleBone Black (BBB) single board computer, an UT-330C environmental logger stick that I plug into my computer once every couple of months to copy the data, and especially with resistors I measure the built-in thermistor using another (5.5-6.5 digit) DMM. The former two are measuring general ambient temperature and the thermistor is measuring temperature at the device under test. I also sometimes use a Pt100 probe connected to a DMM if the device under test does not have a built-in temperature sensor. The sensor in the BBB case has a temperature offset since it's getting a bit warm due to the BBB.

author: RandallMcRee
author_rank: Frequent Contributor
timestamp: November 19, 2023, 06:56:02 pm
content: This works well if you have a PC:https://www.ti.com/tool/TMP117EVMYou can break off the sensor and extend the probe using a four wire ribbon cable or similar.Randall

author: Andreas
author_rank: Super Contributor
timestamp: November 19, 2023, 07:58:53 pm
content: Hello,Just 2 examples.ADC13 is one of my 24 Bit ADCs.There I measure the internal NTC with each Measurement (all ~0.18 seconds) to do a 3rd order T.C. corrrection of the ADC reference voltage.ADC4 (4 temperature sensors) with K2000.ADC4 (24 Bit ADC) measures 4 different NTCs.Channel 3 (CH3) is sitting internal of the K2000.The ADC measures independant of the K2000 and writes the data to a virtual file.The K2000 software measures independant of ADC4 and reads the last measured temperature from the virtual file.So the raw value the temperature compensated value and the Channel 3 temperature can be logged on the K2000 software.If timing is not so critical I use independant 1 minute averages which can be logged together with the time to individual files.Merging is then done via spread sheet for synchronous minutes.with best regardsAndreas

author: dietert1
author_rank: Super Contributor
timestamp: November 20, 2023, 08:25:11 am
content: Data analysis get's more complicated with those amazon temperature loggers, as you have to match the time scale to your metrology log later on. Most likely that requires some hand work. Better get a sensor that delivers data on request, so the data can be logged together with your meter readings.I am using a DIY solution with an SHT35 temperature/humidity sensor that i wired to a STM32 Nucleo evaluation module connected via USB. One can buy a pack of three sensors as evaluation kit and they come soldered to flexible circuit boards. The Nucleo has a built in STLink with an additional CDC serial channel and reports current data every 5 seconds. As the USB stack is inside the on-board STLink, the MCU application is really very very simple. The Win32 host application uses a separate thread to receive and buffer sensor data. I opened one of the back covers of the Prema 6048 to route the I2C cable (60 cm of shielded stereo audio cable) inside and plugged the hole with an old sock.The setup includes a Keithley 2182A whose internal temperature sensor can be read over GPIB and the measurements are near identical.Regards, Dieter

author: DavidKo
author_rank: Frequent Contributor
timestamp: November 20, 2023, 08:54:04 am
content: I use for temperature, humidity and pressure logging BME280 or DS18B20 for temperature (original when 1wire bus is needed or fake in other cases) connected to HA trough ESPHome - wirelessly. Probably you can connect to the device from python script, but I'm not so familiar with python.

author: Rax
author_rank: Super Contributor
timestamp: November 20, 2023, 01:20:19 pm
content: Quote from: dietert1 on November 20, 2023, 08:25:11 amdietert1 knows I've been able to get my bench thermometer (which is also a hygrometer) to send me logs over BT/email, but the alignment of measurements and time is a challenge.I imagine one better option is to have two GPIB devices, start both logs at the same time, have the data collected with a Python script, and then both data strings would implicitly align.Quote from: dietert1 on November 20, 2023, 08:25:11 amThat's awesome! Metrology at its most creative improv!

author: alm
author_rank: Super Contributor
timestamp: November 20, 2023, 01:33:50 pm
content: I consider ambient temperature, pressure etc to not be specifically related to a single experiment, so I log them separately and interpolate the values and use those when analyzing the data. Otherwise life becomes difficult when you're running two experiments at once.

author: Kleinstein
author_rank: Super Contributor
timestamp: November 20, 2023, 04:32:50 pm
content: Usually the room temperature and also humidty influence experiments / instruments with some delay anyway. So the alignment of the data does not have to be very accurate.

author: Rax
author_rank: Super Contributor
timestamp: November 21, 2023, 01:33:29 am
content: Quote from: Kleinstein on November 20, 2023, 04:32:50 pmAbsolutely, great point. Thank you.