We get the data from the Mercury 203.2T counters on RS-485

We get the data from the Mercury 203.2T counters on RS-485
 
 
Organize remote collection of readings from electricity meters - the task is not difficult, the counters are smarter and smarter every year and should send everything themselves, but no, the information is certainly there, but it is scattered. Manufacturers of equipment apparently also want to earn on the sale of their software. I'm writing this article to save time for everyone who has similar tasks.
 
official documentation.
 
 
The counter accepts an ADDR-CMD-CRC byte string, and gives the ADDR-CMD-DATA-CRC, where:
 
 
 
ADDR - The name of the counter (for Mercury 203.2T - coincides with the serial ...
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How we did BelAZ. Part 2 - Laboratory tests

How we did BelAZ. Part 2 - Laboratory tests  
 
In the last article was told about the composition of the electric transmission of a mining dump truck, and in this I will talk about how we started it up at the plant and what problems they faced. From this article you will learn: how to test an electric motor weighing one and a half tons, how to heat air by megawatt and how many boards need to be thrown out to make one.
 
this article .
 
 
This characteristic is removed in the first tests in a completely manual mode. One drive is started in the speed-keeping mode (with a speed PI controller), and then the second drive in torque-keeping ...
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We disperse the backup. Lecture of Yandex

We disperse the backup. Lecture of YandexSeveral next lectures will be based on the first Y. Subbotnik on databases, which took place in the spring . First, Ya.Subbotnik was made by the developer Andrei Borodin. He talked about WAL-G - a simple and effective tool for backing up PostgreSQL in the cloud, as well as algorithms and technologies that allow WAL-G to create backups faster. The main feature of WAL-G is delta-backup. From the lecture you will learn about their implementation and how support for this technology is developing in PostgreSQL.
 
 
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Practical video course of the School of Information Security

It makes no sense to remind once again why it is important to pay attention to security when developing services. We will talk about how to build defense systems, keep them up to date and develop with increasing number of threats. Quite a lot of practical knowledge on this topic can be obtained from the Internet. The theory, in turn, is well covered in several Russian universities. There are many useful literature. But a good security specialist is distinguished not only by knowledge of tools and theory, but by the ability to apply theory in real situations.
 
 
In April of this year, for the first ...
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What is component tests, and what is the SDET?

Abstract
 
The article talks about an unconventional, but useful form of tests, and also sums up the results of seven years of work in the development of tests.
 
Why do we need component tests?
 
After all, there are, say, unit tests, which test in detail the giblets of components. They thoroughly check that the component works in accordance with the concept of the developer. But often this is a test of "buttons", and not how the suit as a whole sits. And not always the behavior conceived by the programmer, coincides with what the customer wanted.
 
And there are, for example, acceptance tests...
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Constructive elements of a reliable enterprise R application

For those who work with R, it is well known that initially the language was designed as a tool for interactive work. Naturally, the methods convenient for the console-based step-by-step application by a person who is deep in the subject are not suitable for creating an application for the end user. The ability to get detailed diagnostics immediately after the error, to overlook all variables and traces, to execute manually the code elements (possibly, partially changing the variables) - all this will be inaccessible when the R application is autonomous in the enterprise environment. (we say R...
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Integer arithmetic. Divide with rounding the result. Part 1

Integer arithmetic. Divide with rounding the result. Part 1The simpler, at first glance, the task, the less the developer thinks about how to implement it correctly, and makes an error at best, at best, discovers it late, at worst - does not notice at all. It's about one of these tasks, namely, on fractional division and on scaling in controllers that support only integer arithmetic.
 
 
Why do not the developers of application programs pay attention to the subtleties of calculations under such arithmetic, the question. I'll venture to just assume that, in all likelihood, the habit of calculating on a calculator is affecting In any case, with an enviable ...
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Simple and efficient calculation of Modbus CRC16 in PLC and MK without bit-shift and tables

The sacred calculation algorithm CRC1? described in the literature and associated with the bitwise shift, fits poorly into the format of the computing capabilities of the PLC and MK. Firstly, in so far as its implementation takes a fair amount of computing resources of the above-mentioned devices, and secondly, because during this calculation the program scan time is significantly extended. The growth of the program scan is due to the fact that, due to the word or byte organization of the accumulator of the arithmetic-logical device, the resultant bit operations with words /bytes in it are performed ...
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How to speed up mobile search twice. Lecture of Yandex

How to speed up mobile search twice. Lecture of YandexOn the phone, web pages often load longer than on a desktop. The developer Ivan Khvatov tells about the reasons for the backlog and how to deal with it. The lecture consists of several parts: the first - about the main stages of loading the page on mobile devices, the second - about the techniques that we use to accelerate the load, the third - about our method of adapting the layout for different speeds.
 
 

 
- Hello everyone, my name is Ivan Khvatov, I work in the search infrastructure. Last time I'm working on speeding up the download of search results. I work with layout, backend ...
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The most difficult program is

From the translator: I found on Quora the question: What program or code can be called the most complex ever written? The answer of one of the participants was so good that it was quite drawn to the article.
 
 
Fasten your seat belts.
 
 
The most complicated program in history was written by a team of people whose names we do not know.
 
 
This program is a computer worm. The worm was written, apparently, between 2005 and 2010. Since this worm is so complex, I can only give a general description of what it does.
 
www.mypremierfutbol.com or ...
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