I’m looking for advice on choosing a decent multimeter
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I have a Victory multimeter with 4.5 digits; it costs around 315 yuan. I also have a Victory signal generator, the VC05+, which costs about 1300 yuan. I used the Victory signal generator to generate a 4.000 signal, and then used the Victory multimeter to measure it – the reading was 4.025 mA. This isn’t acceptable for me; I’m not sure which one is better to use. I mainly use them for calibrating instruments; the signals we typically work with are in the range of 4.000–20.000 mA. Taking practical errors into account, I think it’s necessary to be able to detect values within the range of 4.0000–20.0000. The seller recommended that I choose a six-and-a-half-digit multimeter. I’ve now looked at one model from Tonghui as well as one from Shengli. Those DeTech products do seem a bit expensive. The Tonghui products come with a two-year warranty, and calibration can be carried out annually at a cost of 100 per calibration. Could an expert help me figure out which multimeter I should choose for this purpose? Is it really necessary to go with a model that has six and a half digits? Are there any other brands you can recommend?
An error of 0.6% is unacceptable; in that case you have to use a 6.5-digit device. For ordinary users, simple calibration with the AD584 is sufficient.
Since the magnetostrictive level gauge needs to be calibrated now, with a theoretical accuracy of 0.05% Fs, the current error should also be within 0.05%. Considering a range of 16 mA, the error should be within 0.008 mA
Can I buy those second-hand Agilent items on Taobao?
That multimeter of yours, which costs 315 yuan, is only suitable for general use – for measuring standard current signals. You should use a multimeter that has the capability to measure standard signals, or one with high precision. Multimeters used by general instrument technicians to measure circuit current signals – products from companies such as FLUKE, YOKOGAWA, and HP – are of this type.
This is really low-end; my instruments have an accuracy of 0.05% already
Look at my requirement: it’s unclear whether it’s reasonable to choose 5.5 digits or 6.5 digits. I checked Tonghui’s model 1951, and the display shows 119999; the seller himself isn’t sure either as to why there are two 1s at the beginning. In my understanding, 5.5 digits should mean 199999, with the first 1 representing half a digit