RPM-416 Electrical Parameter Recorder from Novatek-Electro

Today I’m reviewing a product that isn’t exactly unusual, but is definitely quite rare. In my experience, reviews of devices for industrial and specialized applications are few and far between, so with this review I’d like to help fill that gap a little.
So today I have an interesting gadget on my desk with a rather complicated name: an Electrical Parameter Recorder.


The link in the title goes to the Ukrainian version of the site; for readers in Russia, the link is different.

Not long ago, I posted a review of a WiFi electricity meter with overvoltage protection and logging capabilities. In a way, that’s also a recorder, but a very basic one. I’ve already installed it, by the way, and I’ll say a few words about it at the end of this review. The device I’m reviewing can’t disconnect the load, but it can measure a large number of different parameters simultaneously and save all the readings to a flash card. Its field of application is highly specialized, but still fairly broad: you can log what’s happening on your home power supply or at an industrial facility. Its specifications allow it to handle load currents of up to 2000 A, and I suspect that’s not even the limit.

But I’m getting ahead of myself. To keep things in order, I’ll start, as usual, with the packaging.
The box is considerably larger than the ones used for Novatek’s previous devices.


The package contents are clearly more extensive, too:
1. Recorder
2. Manual
3. Patch cable
4. Memory card.



The patch cable is a standard one, two meters long. The included memory card is unbranded and has a capacity of 2 GB. Cards up to 32 GB are supported. As far as I can tell, that limit is due to the FAT32 file system used here.
The manual is practically a tome. Even the table of contents takes up a page and a half, and the 67 pages cover almost every aspect of operating the device.
Rather than copy the whole manual here, it’s easier to download it from this link.


It’s worth noting that this fairly complex device comes with a ten-year warranty. It’s stated both in the product documentation and on the manufacturer’s website, so there’s no mistake.
The only caveat is that the manufacturer recommends servicing the device every six months. This includes tightening the terminals and at least wiping off the dust.


General specifications


Full specifications for the measured parameters.

The key point is that the device can measure 15 parameters simultaneously, plus 3 “virtual” wattmeters whose readings are calculated mathematically from the measured values. That’s what the product page means when it says the device has 18 measurement channels.


Now let’s take a look at the recorder itself.
It has a large gray enclosure, with a sticker on the side containing reminders to make it easy to connect to the Overvis cloud service. I can confirm that the setup really is simple: basically, you just need to configure internet access, then scan the QR code and follow the link.


Of course, it’s considerably larger than the previous devices I’ve reviewed: it’s nine modules wide.
It’s shorter than a standard circuit breaker, and even shorter than a voltage relay. I think that means the top of the front panel will end up flush with the panel of the electrical enclosure.


There are plenty of terminal blocks and connectors, occupying the entire top and bottom of the enclosure.
The top has:
1. Power terminals. The device can be powered not only from a 230 V mains supply, but also from 24 V DC. In my tests, it actually started working at 15–16 V.
2. Four digital inputs for monitoring the closure of external contacts.
3. An SD memory card slot, which is why an adapter is included.
4. An Ethernet cable socket.
5. A socket for connecting expansion modules. The description says you can connect up to four MP-01 modules, but I couldn’t find any information about the modules themselves.


The bottom has:
1. Three mains voltage measurement inputs, with a range of 3–450 V. These inputs are galvanically isolated from the other inputs (except the current measurement inputs), but share a common neutral with each other.
2. Four current measurement inputs. They’re galvanically connected to the voltage measurement input, but since current transformers are used, they’re isolated as well. The inputs are designed for standard CTs with a 5 A output; the software can be configured for ratios up to 2000/5 A.
3. Two temperature measurement inputs for external PTS1000 or PT1000 sensors.
4. A 0–10 V voltage measurement input for standard analog control.
5. 0–20 mA current measurement input, standard “current loop.”



All of this is fully detailed in the wiring diagram.


The front panel has:
1. A backlit 2004 display (20 characters by 4 lines)
2. Five control buttons.
3. Three indicator LEDs.


The manual includes a corresponding description of the controls and indicators.


1. The terminals are good quality and use the proper clamping mechanism; they can accommodate wires up to 2.5 mm².
2. The DIN-rail mounting clip is spring-loaded.
3, 4. It may seem like a minor detail not worth mentioning, but I noticed that the latches on the sides of the case are different sizes, so it’s impossible to assemble it incorrectly. Of course, it would be impossible even without them, but I liked the attention to detail.


Overall dimensions


Before testing it and getting acquainted with the software, I decided to take the instrument apart, especially since it’s very easy to do.
To access the internals, remove the top part of the case by releasing the two side latches.


Inside is a “sandwich” of two boards: the main board and the control/display board.


The top board is held in place by the connectors. The single-row connector on the left simply secures the board, while the two-row connector on the right carries the signal lines. Once assembled, the top of the board is held down by the upper part of the case. Overall, I think it’s simple and reliable.


The layout is fairly dense. The power supply is on the left, the first measurement section is in the middle, and the control circuitry and second measurement section are on the right.


The specified power consumption is 6 W when powered from the mains and 2 W when powered from 24 V, but the power supply section looks considerably more substantial: the input capacitor is 47 µF, which is quite a lot.


1. They didn’t forget to add an input noise filter, fuse, and thermistor.
2. Noise suppression is handled by one X capacitor and a pair of Y2 capacitors made by Epcos, which surprised me a little—I haven’t come across them in equipment for a long time.
3. IRF830 transistor. I didn’t dig too deeply into the power supply circuitry, but as far as I can tell, it’s in the linear regulator circuit that powers the PWM controller when the input voltage is low.
4. The power supply’s switching transistor.


A classic UC3843 is used as the PWM controller. The feedback circuit includes a somewhat unusual component (bottom left, in a white package): an optocoupler with a built-in threshold element, essentially a hybrid of an optocoupler and a TL431.

The power supply has two outputs: one powers the main section, while the other powers the galvanically isolated voltage and current measurement section.


These are the mains voltage and current measurement inputs. Three resistors in the input voltage divider are visible on the left, and four 20 mΩ shunts on the right.


1. Hitano capacitors and some Elite capacitors I’m not familiar with are used in the power circuits.
2. Two optocouplers provide galvanic isolation between the main section and the measurement section.
3. The microcontroller used here has a built-in real-time clock, so a size 14250 battery is installed to power it. Don’t be put off by the 3.6 V marking—it’s not a rechargeable battery, but a primary cell.
4. External connection terminals. One of the two “headers” is visible nearby, presumably for programming the installed microcontroller.


The underside of the board. The assembly is neat, and the soldering was clearly done by machine, though a few small components have shifted slightly. It’s not a problem; I just noticed it. I think they should be installed with adhesive. In any case, there’s no cause for concern: the soldering is good, and the board is very clean.


The voltage and current measurement section is galvanically isolated from the main controller and powered by a separate winding. In this case, a separate small microcontroller handles everything here, while a four-channel op-amp amplifies the shunt signals. I even began to wonder why they added a fourth current channel. If they were already using a four-channel op-amp and the controller had a spare ADC input, why not add one more channel? But that’s just me thinking out loud.

While inspecting the board, I also looked at the clearances between the device’s sections and noticed they weren’t very wide. I was about to complain, but then realized there was no point in making them wider: the common wire for the section shown still has to be connected to earth—or at least to the mains neutral.


The KSZ8051MLL handles communication with the outside world, while everything else is handled by the STM32F107VCT6 controller. It has a 32-bit ARM Cortex-M3 core, 256 KB of flash, 64 KB of RAM, and a 16-channel, 12-bit ADC.


Near the controller, I also found a pair of 23LC1024 chips (1 Mbit SRAM), one 25A2E48 (2 Kbit EEPROM), a TS922A (dual op-amp), and a number of voltage regulators.


The device fully unfolded.


For anyone who says they could build this device for 20 bucks using an Arduino, a smartphone charger, a Nokia display, and fit it all in a shoebox: besides the software, which I’ll talk about next, this instrument is certified. That may not matter for home use, but it could be useful in an industrial setting.

It also comes with a stated 10-year warranty and an operating temperature range of -20 to +45 degrees.


I later noticed that in the manufacturer’s picture, the flash card sticks out quite a bit from the case. In reality, it sits flush with the case.


Along with the logger, they sent me three current transformers for testing. There were several ratings to choose from, and I picked the lowest one, 100/5 A — link. They cost $27 each, with a stated accuracy of 1.5% over a load range of 5–120% — datasheet


The transformers are very compact. They’re designed for the power cable to pass straight through, but they split open, so there’s no need to disconnect anything to install one.
The window measures 26 × 24 mm.
The wires are marked 450/750 V. I couldn’t find any information about their cross-section, but they look substantial even without measuring them.


I also bought a locally made 5/5 A transformer specifically for this review. After all, it’s easier for me to get a current of 5 A than 100 A.
This one looks much more rugged, of course. It even brought back memories of my internship at the Serp i Molot factory in the early 1990s.


And here’s a photo comparing the transformers side by side.


Now I’ll describe the functions, controls, and display of measured values.
The device can be operated entirely through its own interface, without connecting it to a PC. I’ll cover these features briefly, though, because:
1. The 2004 display is reasonably informative, but it can’t compare with the computer software.
2. The controls aren’t particularly convenient either, though they’re perfectly usable. I think we all know that multi-level menus don’t make things any quicker.
3. Virtually all functions and measurement modes are available to the same extent whether you use the device’s controls or the PC software.
4. This display is awkward to photograph: the backlight is comfortable to work with, but not for taking pictures.

Still, I’ll show some of the settings menus and measurement results, especially since remote monitoring requires using the built-in controls anyway.

When powered on, the device displays its name, then switches to the basic display mode, showing the current time and memory card status. The two screens alternate.


1–4. The device menu has 11 items, where you can configure the backlight auto-off, date and time, access password, network access, and more.
5. You can also check the firmware version and MAC address.
6–8. Since the PC software can’t automatically find devices connected to the network, I first had to configure the IP address—or, more precisely, enable DHCP. There are also settings for access through the Overvis cloud service, direct access, FTP access, and so on.
9–12. Basically, there’s nothing complicated in the settings. In almost every case, I just went by intuition, which suggests the developers did give some thought to the menu and settings structure.


There’s a short video on the manufacturer’s website explaining the menu.


Here are a few examples to demonstrate how measured parameters are displayed.
1, 2. Measuring voltage on one of the channels. The display shows not only the voltage itself, but also frequency, harmonic distortion percentage, and peak and instantaneous voltage.
3. I don’t have an RT1000 temperature sensor, but that doesn’t really matter, since it’s a resistive sensor and can therefore be emulated simply by changing the resistance connected to it.
4. The instrument can display not only the measured temperature, but also the sensor status: open circuit or short circuit.
5. In practice, though, “short circuit” or “open circuit” refers to a sensor condition where the calculated resistance corresponds to a displayed temperature outside the range of ±1000 degrees. Positive values are perfectly reasonable, but a temperature of, say, -800 degrees looks a little odd. I think the developers should limit this value in software to at least -273, so as not to violate the laws of physics.
6, 7. In the power measurement (calculation) mode, the display shows apparent, active, and reactive power, the power factor, and active and reactive energy counters in kWh. Because of the limited line width, though, it displays kWh as kWh with one letter omitted.
9. I found a 19th channel, which displays line voltage as well as positive-, negative-, and zero-sequence components.




To use it with a PC, install the software from the manufacturer’s website. Updates are available there too, but I already have the latest version installed. Interestingly, firmware is available in two languages: English and Russian.

The advantage of the software is that you can see everything at once on a single screen. The measured parameters are grouped by phase and color-coded, which is genuinely convenient.


I ran into two minor issues when connecting:
1. The software can’t find the device automatically, even when it’s on the same subnet as the computer. So first I had to check the router to see which IP address it had assigned, then enter that IP in the software settings. I’d call this an oversight, though maybe I’m just used to the fact that, for example, Hikvision camera software can find its devices automatically, even on other subnets.
2. Even if you enter everything correctly, the software may refuse to save the settings. The fix is simple: run the program as administrator. At least, that’s what I had to do during my tests in Win10.
You don’t need to run the software as administrator for subsequent launches or regular use; the issue only came up while configuring the network.

Otherwise, if you do everything I described above, the connection is established very quickly, and after you enter the settings, a message should appear confirming that they were saved successfully.


Once the settings are configured, click Connect.


If everything is configured correctly, you’ll see some measured values on the screen. In this case, almost all of them are zero. The exception for me was the pulse inputs—I ran tweezers across one of them just for the experiment :)


If the connection is lost—as happened to me when rebooting or changing some settings—you get a notification, and the instrument reconnects automatically once the connection is restored.


And here’s what I wanted to discuss separately: the settings. I got the impression that you can configure just about everything—or, if not everything, then certainly a great deal.
The general settings let you set the backlight timeout and adjust the built-in clock. There’s also a button to force synchronization.
The event logging options let you set the logging interval. For example, the default is once per second, but the full range is from 10 ms to 60 min. I’ll come back to this setting later.


There are plenty of options in the network settings too. Note that the FTP server is enabled; it’s disabled by default, and I had to enable it to access the memory card remotely.

The voltage and current measurement options let you set the voltage measurement coefficient and the current transformer rating, up to a maximum of 2000 A. You can’t set it any higher.
Unlike the previous parameters, the temperature sensors can be calibrated and digitally filtered, i.e. Averaging the measured values to eliminate “jitter.”


The low-level analog inputs have no correction, but they do support digital filtering and scaling the signal over a specified range (enabled under Input Type).
The discrete inputs can be configured to respond to a rising or falling edge, and can also be inverted (the device distinguishes between logic levels).

After changing the settings, just click “Write to device” to save the parameters to the device’s memory and apply them immediately. Some parameters require the device to be restarted, but that isn’t necessary when configuring the input ports.


To demonstrate how it works, explore the configuration options, and run some tests, I put together a setup consisting of the device and four current transformers. I simulated the temperature sensors with ordinary 1 kΩ resistors and also connected the low-level analog inputs. The only inputs left unused were the discrete ones.

The four current transformers measured the current in the transformer’s secondary winding. The primary winding was connected to a Variac through the fourth current transformer. I was pleased to find that you can configure the current transformer ratio separately for each input.


I ran into a small snag when connecting the current transformers: the tinned wire ends simply wouldn’t fit, so I had to snip them off and insert the stripped wires instead.


Overall, even though the transformers were right next to each other and I didn’t follow any installation guidelines at all, the readings didn’t vary much—about ±0.4%. The transformers were operating at nearly 1.5 times their rated load, too. As I understand it, the device can display current up to 150% of the rated value.


Since we’re experimenting, I set the current transformer rating to 2000 A, so the device started calculating a proportionally higher current in the primary circuit. In this case, I got readings of up to 3 kA. Since the device supports current transformers rated up to 2000/5 at most, that displayed 3 kA is the upper limit.


It turned out that the current transformer rating doesn’t have to be a multiple of 100 A; you can set it in 1 A increments. In this case, you can make a very rough adjustment to the readings. If the manufacturer had allowed this parameter to be changed in 0.1 A increments, it would have been possible to compensate for current measurement error quite accurately..


As you can see, after this arbitrary change, the readings changed proportionally as well.


While exploring the settings menu, I came across an option to change the voltage measurement input coefficient. At first I thought it was for correcting measurement error, but it turned out not to be. This parameter can only be set in very coarse increments, and only in one direction.
It turned out that this option lets you measure higher voltages by adding an external voltage divider to the device input and setting the corresponding coefficient.


For example, I set the multiplier to 10, 100, and 1000, and got 2.2, 22, and 220 kV instead of 220 V, respectively. But I found an “issue”: the device can display a maximum power of 200000000 kW, or 200 MW (actually 215), and once that limit is exceeded, the readings start to display incorrectly.
On the left, the third input (channel 18) is over the limit; on the right is the value just before it was exceeded. In my opinion, in this situation it would be better to display something like “overload” rather than an incorrect value.


The software turned out to be very convenient to use. It even supports working with several data loggers at once—for example, we have three power feeds at work. I liked almost everything about it, except for one small thing: the interface doesn’t scale to fit the screen. I tried maximizing the program, but essentially nothing changed. It would be so much more convenient if it did.
The point is that this kind of software is sometimes used for monitoring, and not always by people with good eyesight (for example, the former chief power engineer at the company where I work). It would be nice if maximizing the window also scaled up the software interface.


A few tests.

First, voltage measurement. I compared the multimeter readings with those from the device’s first input. The manual specifies an error of up to 1%; in practice, I got closer to 0.2%—an excellent result.


The specified current measurement error is 2.5%. I got no worse than 1%, but bear in mind that I compared it with a clamp meter whose actual measurement error I don’t know. However, in this case the measurement error also depends on the accuracy of the current transformers, so it is not determined by the instrument alone.


I also checked the auxiliary inputs, although in my opinion accuracy is less critical here.


The stated accuracy for the 0–10 V input is 1%, which is 0.1 V of the full range. The actual error was 0.084 V, just barely within spec. In addition, the digital filter is set to 1.5 seconds by default, but in reality the voltage changed much more gradually: for example, it took about 5–6 seconds to stabilize after a 2.5 V change.


As for the 0–20 mA current input, there’s no point even quoting the stated accuracy, since its readings matched those of a much higher-grade multimeter almost exactly.


The temperature results were somewhat worse, since I don’t have any reference standards—or even the PTC1000 temperature sensors themselves. But we’re simple folk, so let’s try another approach.
The PTC1000 and PT1000 temperature sensors are thermistors, so you can connect an ordinary resistor to the instrument’s input and use a table to calculate the corresponding temperature.
But the table is rather coarse, with a temperature resolution of 1 degree, so in the end I used an online calculator.


1. −2.6 degrees, resistance 0.9924 kΩ, calculated temperature −1.94 °C
2. +4.4 degrees, resistance 1.02 kΩ, calculated temperature 5.12 °C
3. +43.9 degrees, resistance 1.1756 kΩ, calculated temperature 45.23 °C

In tests 1 and 3, the resistor was connected to the first input; in test 2, to the second.

The instrument’s stated accuracy is ±1.5 degrees. It stays within this limit up to around 60–70 degrees, but the error increases as the temperature rises, so you’ll need to apply a correction. Fortunately, that option is available.


And the last test: the digital inputs.
For this test, I connected a signal generator output to the instrument’s input. The test is somewhat pointless, of course, since the instrument’s measurement accuracy is determined by its crystal oscillator, so I was really testing the generator rather than the instrument. But I was more interested in the maximum frequency it could measure.
The manual specifies a maximum of 15,000 pulses per minute, or 250 Hz. I managed to get twice that: the instrument measured frequencies up to 500 Hz. But if, for example, you set it to 600 Hz, it starts displaying 24,000 instead of 36,000; at 700 Hz, it showed 18,000 instead of 42,000.
In any case, the instrument handled twice the specified range, which is pretty good.


One of its main functions—in fact, it’s right there in the name—is the data logger.
The device records data in frames containing the date, time, and 18 measured and calculated parameters corresponding to the channel number, for a total of 20 values. The frame size is fixed at about 90 bytes. The device can record frames at different rates, from 1,000 times per second down to one frame every 60 minutes. The default is one frame per second, so a 2 GB memory card will hold about 7 months of continuous recording.
You can also set the maximum file size, but bear in mind that because of the way the data is structured, a frame that starts recording at, say, 22:15 one day and finishes at 03:23 the next will be split between two files. In other words, the logger can’t record several days into a single file. That’s not very convenient for analysis, but it does make downloading files easier.

The logger can record “out of the box”: just select “Record” either on the logger’s panel or in the software. But to read the data, you first have to go into the settings and enable FTP access.
After that, a “Memory Card” button appears in the software. Click it to open the file explorer, where you’ll find your memory card. To work with a file, you first have to copy it to your computer. You can't work directly with files on the memory card, which is inconvenient too.


To work with recorded files, click the View RDF button. This opens a separate window for the recorded-file analysis program.
Here you can choose which parameters to display, set the line color and thickness and the marker size, and convert the data to CSV format.


It would all be fine if not for one thing: the program plots data on only two axes, time and value, so you get a single vertical scale with one range. That's not very convenient when analyzing several parameters with very different values at the same time (look at the green curve).


In this respect, I can say that it's much more convenient when a graph has two vertical scales, for voltage and current, for example, as on ZKEtech electronic loads. You can also display a third vertical scale for power, highlighted in a different color.


Since CSV export is available, I checked the measurement rate.
First, I set the recording interval to 10 ms, i.e. 100 times per second, and looked for the smallest voltage change in the file. The measurement rate turned out to be no more than 40 ms, or 25 times per second. It may be higher, but that's the fastest interval I found.


Next, I was curious about the sampling rate for digital signals. I set the recording rate to 1,000 times per second (1 ms) and applied a 300 Hz square wave to the input. I immediately found out two things:
1. The file contains only zeros and ones, not accumulated values.
2. The instrument can even record a single value per frame, so the recording rate is really very high and exceeds what the inputs themselves can handle, which is necessary for accurate measurement.

Naturally, in this and the previous recording modes, the data rate is no longer 90 bytes per second, but 9 or 90 KB, respectively, and 2 GB no longer seems like all that much.


In addition to the software, the data logger has its own web interface. I'll get ahead of myself and say that using the software doesn't disable the front-panel controls, and you can even operate it from five places at once (tested):
1. From the front panel
2. From the software
3. Through the web interface
4. Through the Overvis service on a PC
5. Through the Overvis service on a smartphone

To connect over your local network, all you need is the data logger's IP address, the password, and any browser. The interface looks quite user-friendly.


But beyond that, things aren't so straightforward. Yes, it displays all the measured parameters, just like the software, but here we run into the same problem: the interface doesn't scale, so the parameters appear as one long list...
It would be nice if the interface could scale, or if it used graphs like the software.

There's no point explaining the details, since otherwise it offers the same options for displaying measured values as the software.


The third connection method is through the Overvis cloud service.
To get access, you first need to enable the corresponding option in the device settings.


At first I planned to explain how to connect, but then decided you could figure it out without instructions. Instead, I'll focus on a developer oversight I ran into along the way.



I set up the connection and registered for the service on my smartphone. I already had an account that I use with the EM-129, but it wasn't accepted, so I had to register again.
But that's not the point. I think anyone who's used a smartphone knows that the first character in some text fields is often automatically capitalized. And that's where the problem lies.

After registering on my smartphone, I logged into the service, connected to the data logger, poked around a bit, and decided to log in from my PC. I entered my email and password and got an error.
I didn't get it, I thought. The email was right, the password was right, but it wouldn't let me in... It didn't take long to figure out: the email, which in this case is also the username, is case-sensitive. Dear developers, please note that worldwide, usernames—and especially email addresses—are case-insensitive!


In the end, I could only log in after entering my email with a capital first letter.

The interface here is even more different, and in my opinion, for the worse. Yes, technically, it offers a great many options and features—even more than the software and web interface—but it’s less convenient to use.


At first glance, everything here is just like in the web interface: it displays the measured values. The only difference is that the information refreshes much more slowly than in the software.


On the other hand, you can configure more settings for each parameter. I find it hard to judge, though, since some of them were unclear to me.


Unlike the previous connection options, however, the Overvis service lets you upload data to the cloud and do a basic analysis without downloading files. The update rate is lower, of course, but still quite sufficient for a rough assessment.
One drawback is that you can analyze only one parameter at a time; displaying two simultaneously isn’t possible.
I also found a small “glitch” here, highlighted in blue: the time doesn’t always move forward; sometimes it goes backward :)


In addition to displaying numerical values, the Overvis service can plot the selected parameter, which can be very handy. In other words, recording with the device is fast and convenient, and lets you view many parameters at once. Overvis, on the other hand, lets you view simplified graphs without enabling recording on the device or transferring files to your computer.


I’ll keep my comments on accessing Overvis from a smartphone brief, especially since it essentially works just like access from a PC.


You can also view current values and data saved in the cloud, and plot graphs, although zooming in and out is noticeably more difficult here.


Worse still, even with the same resolution on my smartphone and monitor, viewing the data on the phone is noticeably less convenient. In portrait orientation, some of the values extend beyond the screen, so you have to swipe left and right. In landscape orientation, very few rows of values fit on the screen.
That said, I can’t say it doesn’t work: everything works just as it does on a PC, with the same analysis and configuration options.


Unfortunately, I don’t currently have the technical means to test the logger on a three-phase supply. That would be not only more appropriate, but also more interesting. I’ll try to do it when I get the chance, especially since I’m curious myself.
For now, though, I can share a report from the EM-129 energy meter. I mentioned in my review that I planned to install one at home.

I replaced the old voltage relay with an EM-129 and RN-11 setup, which has been running for 18 days now. There hasn’t been a single failure or false trip during that time.


The device reliably records all the parameters. It’s especially interesting to see how the load and mains voltage changed over the course of a day.


There is one minor bug in the meter’s software. It’s not serious, but it’s there, and I’ve notified the developer.
The meter calculates everything correctly and tracks daily consumption, but for some reason it transfers the data to the daily counter not at 00:00, but at 3:00. As far as I can tell, the data is transferred correctly for the 00:00–00:00 interval; it’s just that the process itself happens at 3 a.m.


So far, it has “clocked up” more than 100 kWh, but it hasn’t been very hot and the air conditioners were off. Otherwise, the figure would have been noticeably higher.


And now, the conclusions. I’ll try to keep them brief.
In terms of construction and circuit design, I liked the device. It’s genuinely well thought out, with good circuitry, extensive functionality, lots of parameters measured simultaneously, and flexible settings.

I liked that it can be powered by practically “anything”: you can supply 24 V DC or 250 V AC, and the device works without even noticing the difference. Still, I do have one suggestion for the developers. We live in a world where local networks seem to be everywhere, and network designers came up with a very convenient solution for applications like this: PoE. In my opinion, it would be a great fit here, especially since you’re more likely to find it on an enterprise network. It solves several problems at once: power is supplied over the Ethernet cable, and it’s often backed up by a UPS.

My only concern about measurement accuracy was the temperature measurement. As I mentioned, though, this parameter can be calibrated—in fact, it’s the only one that can. You could also question the accuracy of the 0–10 V measurement, but it was within the specified tolerance. Although the ability to calibrate the other parameters would be useful too, at the very least it would be good to calibrate the current measurement inputs or, as I mentioned, set the current transformer rating in 0.1 A increments rather than 1 A.

Software, controls and display.
Well, this isn't entirely straightforward, so let me explain:
1. Local controls. 5 points. Everything is intuitive and easy to operate, even given the technical limitations (a 2004 display, three LEDs and five buttons).
2. Standalone software. It looks great, displays the parameters very clearly and is easy to configure. I'd give it 5 points if not for a couple of minor issues: there's no interface scaling, and the graphs aren't displayed very conveniently. So, 5-.
3. Web interface. Generally convenient and intuitive, but the interface seems designed for a portrait-oriented screen, so it's not as clear on a regular PC. 4 points here, although if you're working on a PC, it's easier to launch the standalone program.
4. Overvis service. It has more options and can write data to the cloud as well as to the card, albeit slowly. But the interface is very inconvenient, so I'd give it around 4-. The main advantage is cloud recording; it can be useful when you really need it.
5. Overvis on a smartphone. A generous 3 points, because using it on a smartphone is only practical if you really have to. For regular use, it's a nightmare...

As you can see, all the issues mentioned are related to the interface in one way or another, and I think the developers have some things to think about here. I really liked the device itself, and I hope the manufacturer improves its remote control and monitoring.

That's all for today. Of course, there's a lot I haven't covered; I forgot some things along the way, and there are some topics I'd like to discuss in more detail, but there's simply too much to fit into one article. So I think it'll be easier to answer questions as they come up, especially since a representative of the developer may be able to answer some of them—that would be more accurate and appropriate.