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EEVBlog 121GW Discussion thread
beanflying:
--- Quote from: matemathieu on August 05, 2022, 01:12:30 pm ---Hi,
I found it is not possible to report an issue on the store page here:
https://www.eevblog.com/product/121gw/
Hence have an issue to report.
According to the current version of the manual, the thermocouple reading cannot be calibrated.
One simple way of doing it is to use boiling/freezing water.
Capture the max temp when you put a K-type probe into your home boiler, make sure it does not touch the bottom where the heater is and you have the first point.
Water with ice would be the second one. Put water with lots of ice, wait. Make sure the probe end-tip does not touch the ice and capture the lowest value.
Is that a good idea?
Best
--- End quote ---
To some degree (no pun intended ;D ) there is not a huge need to try and 'calibrate' the meter with a K type thermocouple. 'Roughly Checking the Calibration' is about all you can do with your method.
Generally accepted accuracies Type K ±2.20C or ±0.75%
While the 121GW's spec is less than that Temp °C, -200 to 1350°C, K-Type, 0.1°C (resolution), ±0.5%+3°C (stated accuracy)
So inherently because of this you can not get a reading more 'accurate' or known under the spec of the meter. The Meter if it was to be calibrated on the Temperature range would more likely be done against a calibrated source instead.
matemathieu:
--- Quote from: beanflying on August 06, 2022, 01:36:01 am ---To some degree (no pun intended ;D ) there is not a huge need to try and 'calibrate' the meter with a K type thermocouple. 'Roughly Checking the Calibration' is about all you can do with your method.
Generally accepted accuracies Type K ±2.20C or ±0.75%
While the 121GW's spec is less than that Temp °C, -200 to 1350°C, K-Type, 0.1°C (resolution), ±0.5%+3°C (stated accuracy)
So inherently because of this you can not get a reading more 'accurate' or known under the spec of the meter. The Meter if it was to be calibrated on the Temperature range would more likely be done against a calibrated source instead.
--- End quote ---
It got a 100ºC error @600ºC.
Then I checked by dipping it into boiling water and it showed 107ºC.
Then I realized it was partially due to the low battery of the unit, I changed them, and it got back to something in the specs.
ve2mrx:
Remember that the temperature of the meter is part of the temperature reading, the K-type thermocouple measures temperature difference between both ends, not a temperature like a thermistor!
Calibrating the meter would only be for a specific probe. It's best to check the accuracy of the meter's internal temperature reading and calculate the offset the probe adds to it. Maybe do two points with the probe and derive an equation from the measurements and attach it to the probe. You would then correct the meter temperature and add the probe correction to it to get a final temperature... Or use a dedicated precision measurement system like a 4-lead platinum probe.
Martin
JDW:
I purchased a 121GW brand new from the official store in Jan. 2023, and I then downloaded the Meteor app for my iPhone. It works well enough via Bluetooth communication, but I wanted to compare with the official 121GW iOS app here. Sadly, it says Not Available regardless of whether I am signed in with my Apple ID for the USA or my other Apple ID for Japan. Is it region locked to Australia (which would be crazy)? Or is the official app totally dead on iOS for some reason?
The reason I even ask is because I dislike the Meteor app because it lacks a FREEZE/HOLD feature. When logging data with the app via Bluetooth, I want to be able to tap the iPhone screen or a button in the app to freeze the waveform display so I can better examine it. If I stop logging, the frustrating Meteor app dims out the waveform display, making it harder to see! I wanted to download the official 121GW app to see if it works better than Meteor in that regard. But again, I can't find the iOS official app anywhere now in 2023!
EEVblog:
--- Quote from: JDW on February 19, 2023, 09:19:59 am ---I purchased a 121GW brand new from the official store in Jan. 2023, and I then downloaded the Meteor app for my iPhone. It works well enough via Bluetooth communication, but I wanted to compare with the official 121GW iOS app here. Sadly, it says Not Available regardless of whether I am signed in with my Apple ID for the USA or my other Apple ID for Japan. Is it region locked to Australia (which would be crazy)? Or is the official app totally dead on iOS for some reason?
The reason I even ask is because I dislike the Meteor app because it lacks a FREEZE/HOLD feature. When logging data with the app via Bluetooth, I want to be able to tap the iPhone screen or a button in the app to freeze the waveform display so I can better examine it. If I stop logging, the frustrating Meteor app dims out the waveform display, making it harder to see! I wanted to download the official 121GW app to see if it works better than Meteor in that regard. But again, I can't find the iOS official app anywhere now in 2023!
--- End quote ---
I didn't do anything with the IOS app, it hasn't changed since the original release, so AFAIK should still be available. I don't have an iPhone so I can't check.
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