I bought a second-hand multimeter and calibrated it.

littleshrimp

I bought a second-hand multimeter and calibrated it. [Copy link]

 

I don't usually measure anything precise, and the 3.5-digit multimeters I have are enough. This time I wanted to measure a set of battery voltages and compare it with another measurement chip. I thought I would only use it once, so I spent 1,800 to buy a second-hand Keithley 2000. Because this meter is no longer in the calibration period, I was still young when I bought it, and I thought that 200 to 300 yuan would be enough to calibrate a meter. After I bought it, when I compared it with another chip, the voltage difference was 60mV, which was ridiculous. I was going to find the Metrology Institute to do a calibration. I couldn't get through on the phone over the weekend. Today I contacted them and asked about the price of 1,500, which would take 7 days. Both the time and the price were unacceptable. This time I finally understand why playing with high-level meters is called fever. Whether it is new or old, the calibration fee of 1,500 a year is really too much for me.

dcexpert

Second-hand instruments are very difficult to find

IC爬虫

You can make your own voltage and current benchmarks

I was very keen on this when I was in college, but I never used it again after I started working.

littleshrimp

IC Crawler published on 2022-7-18 15:29 You can make your own voltage and current benchmark. I was very interested in this when I was in college, but I never used it again after I started working.

Does the benchmark also need to be calibrated regularly?

nmg

See if there is any calibration service on Taobao, it will probably be cheaper.

chunyang

The key is that a sufficiently high-precision benchmark is very expensive. The higher the precision of the instrument, the higher the requirement for benchmark accuracy. Calibration must follow the standard process, and the cost is definitely not low...

吾妻思萌

Basically, metrology and testing means that if you don’t open for business for three years, you can make a living for three years after you open it.

eric_wang

When I first started working, I was doing concrete test block experiments in the laboratory. I was particularly impressed. It was an ordinary electronic platform scale for weighing things. It was sold on the market for less than 100 yuan. A third-party agency calibrated it for 100 yuan and gave a paper calibration certificate. If you go directly to the calibration agency to buy it, it costs 200 yuan. . .

btty038

Second-hand water is very deep. Rent an instrument to test it.

qwqwqw2088

Second-hand multimeter calibration needs to be done at a qualified place, and these places charge this kind of fee.

秦天qintian0303

Metrology and testing still rely on mandatory means to make money. There are many industries that require inspection tools to be measured. Other metrology institutes have metrology qualifications. I envy them.

wangerxian

Is calibration so expensive? Do precision instruments need to be calibrated regularly? I just heard about this . I used to think it was just for direct use. Maybe I haven't come into contact with such precision instruments.

littleshrimp

nmg Published on 2022-7-18 16:03 See if Taobao has a calibration service, it will probably be cheaper

I think there should be a cheaper third-party agency to mail it. It will take longer and it will be too late.

littleshrimp

chunyang published on 2022-7-18 16:09 The key is that a sufficiently high-precision benchmark is very expensive. The higher the accuracy of the instrument, the higher the requirement for benchmark accuracy. Calibration must follow the standard process, and the cost is definitely not high...

I used to see that the price of the LTZ1000 benchmark was very expensive. Now it seems that if the long-term stability is good, it is still very cost-effective for personal use and can save a lot of calibration costs.

littleshrimp

eric_wang posted on 2022-7-18 16:23 When I first started working, I was doing concrete test block experiments in the laboratory. I was particularly impressed by the electronic platform scales used to weigh things. They were sold for less than 100 yuan each on the market. The first...

The equipment in the unit sometimes needs to be calibrated, and this premium cannot be saved.

IC爬虫

littleshrimp posted on 2022-7-18 15:35 Does the benchmark also need to be calibrated regularly?

Yes, but it's usually better to watch it once in a long time.

littleshrimp

btty038 posted on 2022-7-18 16:57 Second-hand water is very deep. Rent an instrument to test it

I don't know where to rent it.

littleshrimp

qwqwqw2088 posted on 2022-7-18 17:19 You need to go to a qualified place to calibrate a second-hand multimeter. These places charge this kind of fee

If it's more expensive, you might as well just buy a new watch.

littleshrimp

Qintianqintian0303 published on 2022-7-18 17:24 Metrology testing still relies on coercion to make money. There are many industries that require inspection tools to be measured. Other metrology institutes have metrology qualifications. I envy them.

I asked the two metrology institutes in Shenyang and Dalian and they both have the same price. I wonder if some calibrations must be valid with a certificate from the metrology institute. This kind of industry without competition is really enviable.

littleshrimp

wangerxian posted on 2022-7-18 17:35 Is calibration so expensive? Do precision instruments need regular calibration? I just heard about this. I used to think that they could be used directly. Maybe I haven't come into contact with this...

A three-and-a-half-digit multimeter also needs to be calibrated. If you want to obtain certain qualifications, you need to calibrate it every year.
The instrument has long-term drift. If you have requirements for accuracy, you also need to calibrate it for personal use.