Robiton PM1 and PM2 power meters
Recently, I told you why you need a special device - a power meter (wattmeter) for accurate measurement of the power of electrical devices that operate on the network, and any measurements using conventional multimeters cannot be accurate.
I bought my first BEBUY power meter five years ago in one of the Chinese online stores. He, like many other similar meters, is quite accurate when measuring power from tens of watts, but at low power the measurement accuracy decreases.
In one of the reviews of LED lamps on the website led-obzor.ru I saw a photo of a power meter that showed power values with hundredths. I asked the author of the site, what kind of meter. Turned out to be Robiton. This manufacturer has two models of power meters: Robiton PM-1 and Robiton PM-2 . I asked the representatives of the brand to provide me with both models for close study.
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The devices do not differ much in price (PM-1 costs 780 rubles, PM-2 is white in color - 900 rubles, and black - 1000 rubles), but it is very different in terms of capabilities and measurement accuracy.
Both devices are included in the euro outlet, and the load, the power of which is to be measured, is connected to the outlet on the device body. Both instruments have three control buttons. Both devices are capable of measuring power up to 3600 watts.
Robiton PM-1.
The device measures the power, the amount of energy consumed by the load (kilowatt-hours), and the cost of the energy consumed. The price of a kilowatt is customizable.
The resolution in power measurement is not very high, therefore, with a load of 6 W, the readings of the device all the time “jump” between 5.5 and 6.4 W.
The Robiton PM-1 power meter is suitable for measuring the power and cost of energy consumed by medium and high power electrical appliances - computers, heaters, teapots, refrigerators, washing machines.
Robiton PM-2 has much more features and higher accuracy.
Three batteries are used to work the built-in clock and save the readings after disconnection from the mains.
The device displays time, mains voltage, frequency, current, load power, power factor (Power Factor), measurement time, the amount of energy consumed by the load (kilowatt-hours), and the cost of consumed energy. The price of a kilowatt is adjusted taking into account day and night consumption with two-tariff accounting. It is possible to reset the measurement time, energy consumption and cost.
The manual Robiton PM-1 indicates the accuracy of power measurement ± 0.1 W at a load of up to 100 W and 1% with a load of more than 100 W. For Robiton PM-2, the power measurement accuracy is ± 1% or ± 0.2 W, the voltage measurement accuracy is ± 1% and the current measurement accuracy is ± 1% or ± 0.01 A.
In order to understand how accurate wattmeters are, I used my entire arsenal of measuring instruments.
As a source of reference voltage of 230 V, I used an uninterruptible power supply with a pure sine wave APC Smart UPS 700INET in battery mode.
The most accurate of my multimeters - Mastech MY65(accuracy ± (0.1% + 3), ie ± 0.53 V to 230 V ) showed 231.2-232.0 V. Presumably, the source gives 231.5 V. Robiton PM2 honestly showed 232 V. Multimeter UNI-T UT61E overestimated the readings, but its accuracy is ± (0.8% + 10) which is only ± 2.84 V at 230 V.
upd .: I made a mistake with the accuracy of the multimeter Mastech MY65, and the Chinese have failed. The box on the multimeter says "AC Voltage 750V ± (0.15% + 3)" i.e. ± 0.65 V to 230 V, in the Russian manual attached to the multimeter ± (1% + 15), that is, ± 3.8 V to 230 V, on the official website ± (1.2% + 15) , i.e. ± 4.3 V to 230 V. To believe I do not know.
As a low-power measuring load, I used a 27 kΩ 2 W resistor. MY65 (accuracy ± (0.3% + 1)) showed that its resistance is 26950 Ohms. The power should be 231.5 / 26950 * 231.5 = 1,9886 watts. Robiton PM-2 showed 1.99 watts. Perfectly accurate!
Robiton PM-1 showed alternately 1.8 and 2.0 watts.
In addition, I measured the power of incandescent bulbs 25 and 75 watts. PM-1 showed 25.7 and 75.4 W, PM-2 - 25.95 and 75.58 W.
I had the opportunity to compare the results of measuring the power of a Robiton PM-2 wattmeter with the results obtained on expensive laboratory equipment for measuring power, and even on a load with a low power factor and "ragged" consumption - LED lamps. Ten different samples of lamps with power from 3.4 to 13.8 W deviations ranged from 0.2% to 2.1%. Excellent result!
Despite the wide range of measurements, the Robiton PM-2 gives very accurate results even at low power.
In order to open the power meters, you need a tricky three-sided screwdriver. The PM-1 design consists of two boards.
There is a calibration button on the indicator board. I decided not to risk it and not to press it.
Measuring shunt.
The reverse side of the main board.
Robiton PM-2 design.
Main board and shunt.
Payment from the reverse side.
The power meter is an inexpensive and useful device that allows you to find out how much various electrical appliances consume. Using it, you can find out how much a refrigerator consumes per day, how much a washing machine consumes per wash, or find out how much it costs to boil a kettle. With the help of this device, you can determine which electrical appliances in the house consume the most energy (believe me, these are far from the most powerful appliances) and learn how to save electricity.
Of the two wattmeters of Robiton, I, of course, recommend the Robiton PM-2 - it is more accurate and has much greater capabilities.
2016, Alexey Nadyozhin.
I bought my first BEBUY power meter five years ago in one of the Chinese online stores. He, like many other similar meters, is quite accurate when measuring power from tens of watts, but at low power the measurement accuracy decreases.
In one of the reviews of LED lamps on the website led-obzor.ru I saw a photo of a power meter that showed power values with hundredths. I asked the author of the site, what kind of meter. Turned out to be Robiton. This manufacturer has two models of power meters: Robiton PM-1 and Robiton PM-2 . I asked the representatives of the brand to provide me with both models for close study.
')
The devices do not differ much in price (PM-1 costs 780 rubles, PM-2 is white in color - 900 rubles, and black - 1000 rubles), but it is very different in terms of capabilities and measurement accuracy.
Opportunities
Both devices are included in the euro outlet, and the load, the power of which is to be measured, is connected to the outlet on the device body. Both instruments have three control buttons. Both devices are capable of measuring power up to 3600 watts.
Robiton PM-1.
The device measures the power, the amount of energy consumed by the load (kilowatt-hours), and the cost of the energy consumed. The price of a kilowatt is customizable.
The resolution in power measurement is not very high, therefore, with a load of 6 W, the readings of the device all the time “jump” between 5.5 and 6.4 W.
The Robiton PM-1 power meter is suitable for measuring the power and cost of energy consumed by medium and high power electrical appliances - computers, heaters, teapots, refrigerators, washing machines.
Robiton PM-2 has much more features and higher accuracy.
Three batteries are used to work the built-in clock and save the readings after disconnection from the mains.
The device displays time, mains voltage, frequency, current, load power, power factor (Power Factor), measurement time, the amount of energy consumed by the load (kilowatt-hours), and the cost of consumed energy. The price of a kilowatt is adjusted taking into account day and night consumption with two-tariff accounting. It is possible to reset the measurement time, energy consumption and cost.
Accuracy of measurements
The manual Robiton PM-1 indicates the accuracy of power measurement ± 0.1 W at a load of up to 100 W and 1% with a load of more than 100 W. For Robiton PM-2, the power measurement accuracy is ± 1% or ± 0.2 W, the voltage measurement accuracy is ± 1% and the current measurement accuracy is ± 1% or ± 0.01 A.
In order to understand how accurate wattmeters are, I used my entire arsenal of measuring instruments.
As a source of reference voltage of 230 V, I used an uninterruptible power supply with a pure sine wave APC Smart UPS 700INET in battery mode.
The most accurate of my multimeters - Mastech MY65
upd .: I made a mistake with the accuracy of the multimeter Mastech MY65, and the Chinese have failed. The box on the multimeter says "AC Voltage 750V ± (0.15% + 3)" i.e. ± 0.65 V to 230 V, in the Russian manual attached to the multimeter ± (1% + 15), that is, ± 3.8 V to 230 V, on the official website ± (1.2% + 15) , i.e. ± 4.3 V to 230 V. To believe I do not know.
As a low-power measuring load, I used a 27 kΩ 2 W resistor. MY65 (accuracy ± (0.3% + 1)) showed that its resistance is 26950 Ohms. The power should be 231.5 / 26950 * 231.5 = 1,9886 watts. Robiton PM-2 showed 1.99 watts. Perfectly accurate!
Robiton PM-1 showed alternately 1.8 and 2.0 watts.
In addition, I measured the power of incandescent bulbs 25 and 75 watts. PM-1 showed 25.7 and 75.4 W, PM-2 - 25.95 and 75.58 W.
I had the opportunity to compare the results of measuring the power of a Robiton PM-2 wattmeter with the results obtained on expensive laboratory equipment for measuring power, and even on a load with a low power factor and "ragged" consumption - LED lamps. Ten different samples of lamps with power from 3.4 to 13.8 W deviations ranged from 0.2% to 2.1%. Excellent result!
Despite the wide range of measurements, the Robiton PM-2 gives very accurate results even at low power.
What's inside?
In order to open the power meters, you need a tricky three-sided screwdriver. The PM-1 design consists of two boards.
There is a calibration button on the indicator board. I decided not to risk it and not to press it.
Measuring shunt.
The reverse side of the main board.
Robiton PM-2 design.
Main board and shunt.
Payment from the reverse side.
Conclusion
The power meter is an inexpensive and useful device that allows you to find out how much various electrical appliances consume. Using it, you can find out how much a refrigerator consumes per day, how much a washing machine consumes per wash, or find out how much it costs to boil a kettle. With the help of this device, you can determine which electrical appliances in the house consume the most energy (believe me, these are far from the most powerful appliances) and learn how to save electricity.
Of the two wattmeters of Robiton, I, of course, recommend the Robiton PM-2 - it is more accurate and has much greater capabilities.
2016, Alexey Nadyozhin.
Source: https://habr.com/ru/post/392827/
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