Desk counter SC 62KE is urgently needed, and the amount is large

Wuxi Riheng Electronic Technology **** has been doing this table for more than 10 years, you can check their company**. The technical service is in place. They **0510-83505557

Passenger flow counters are generally used in simple or complex passenger flow gathering places, the general simple passenger flow counters are hundreds of pieces, and complex passenger flow places require high accuracy, between more than 2,000 and 5,000, of course, foreign passenger flow counters as many as 10,000 pieces.

According to the use scenario and needs, ** is different. Simple only need customer flow ** is very cheap, reference to Zhike 01 only needs about 300, if you need to count and analyze the store customer flow, customer flow trends, sales and customer flow relationship and other data analysis, software and hardware combined, Zhike 02 only needs about 500, these are infrared technology, easy to install, accuracy rate of 95%...

Depending on the requirements, the function provision is also different. Refer to Yaliang Store Treasure, which is roughly divided into simple customer flow statistics equipment** is about 2000, if there is a customer group analysis needs, you can choose a device with face recognition function, the market ** is about 7000, the specific ** is different, it is recommended to choose a customer flow counter when comparing the market**.

It depends on what you're using it for? On the bus, in the mall, in the shop or at the airport? If it is on the bus, it will also be different according to the model (air suspension car or steel plate suspension car), the number of doors, the length of the vehicle, etc. Generally, ** is about 20 million yuan.

Cheap, if you are used in the retail industry, more than 3000 can be bought, I have it in my clothing store, in a place called Shanghai Baozi Electronic **** to buy.

JS makes it easy to do this. But just like that, when you close the page and reopen it, the counter goes to zero. Since you don't have backend support, there's no way to save the amount of traffic you already have.

I don't know what language you use to make a web page, but it can give you an idea.

You can save the number of visits in a file or database, read the value with each click, and then add 1 to this and save it. Of course, when performing this operation, it is necessary to lock it so as not to have conflicts when two people access it at the same time.

Write a whole bunch of them. I won't write it, but I'll give you an idea. AJAX with JS

And finally this backend page returns a piece of data, based on this data prompt. Success or failure.

Let's use the database and record the data in the database.

To put it bluntly, it's the server's ability to withstand it. First, confirm that the server hardware is sufficient to support the current traffic.

Ordinary P4 servers can generally support up to 100,000 unique IPs per day, if the number of visits is larger than this, then you must first configure a higher performance dedicated server to solve the problem, otherwise no matter how you optimize it, it is impossible to completely solve the performance problem.

Second, optimize database access.

An important reason for the excessive load of the server is that the CPU is overloaded, and reducing the load of the server CPU can effectively break the bottleneck. The use of static pages minimizes the load on the CPU. Of course, it is best to implement complete static in the foreground, so that you don't need to access the database at all, but for frequent updates, static often can't meet some functions.

Another solution is caching, which is to store dynamic data into cached files, which are called directly by dynamic web pages without having to access the database, which is heavily used by WordPress and Z-blog. I myself wrote a counter plugin for z-blog, which is also based on this principle.

If you really can't avoid access to the database, then you can try to optimize the query sqlAvoid using statements such as select *from and return only the results you need for each query, avoiding a large number of SQL queries in a short period of time.

Third, external hotlinking is prohibited.

External ** or file hotlinking often brings a lot of load pressure, so the external ** or file hotlinking should be strictly restricted, fortunately, at present, you can simply control the hotlink through refer, Apache itself can prohibit hotlinking through configuration, and IIS also has some third-party ISAPI that can achieve the same function. Of course, forging refer can also be achieved through **, but at present, there are not many deliberate fake referrer hotlinking, so you can ignore it first, or use non-technical means to solve it, such as adding a watermark to **.

Large files can take up a lot of traffic, and for non-SCSI hard drives, a large number of files will consume the CPU, making them less responsive. Therefore, try not to provide large files larger than 2M**, and if you need to provide them, it is recommended to put large files on another server. There are quite a few free ones that offer sharing and file sharing features, so you can try to upload your files to these shares.

Counter error**1, quantization error 2, trigger error 3, standard frequency error.

A digital instrument that uses digital circuit technology to count the number of pulses passing through in a given time and display the counting results. Electronic counters are the basis for other digitized instruments. Various analog-to-digital converters can be connected to its input channel, and various digital instruments can be made by using the corresponding transducers.

The advantages of electronic counters are high measurement accuracy, wide range, multiple functions, simple operation, fast measurement speed, direct display of numbers, and easy to realize the automation of the measurement process, which is widely used in industrial production and scientific experiments.

Error of the counter**.

1. Quantification error.

2. Trigger error.

3. Standard frequency error.

The counters of ** are now mostly divided into two situations, one is implemented with ASP written **, and the other is implemented with **promotion, that is, it is implemented with embedded in other **.

I feel that the general ** doesn't spend too much energy writing ASP ** now, and it's not very good to embed other ** **, such as adding ads to you and the like, and the general small station can also be done without counters. It's not much use if you use it. It's true.

The maximum pulse frequency is only 416Hz, and both methods can be simple.

Damn, God-man. How fast is your photoelectric corresponding.

With timing and comparison. What is M-Law?