Web Application for Weight Data Collection
Whenever industrial scales are used to weigh items, the weight obtained is used for some purpose. One common situation is the use of a platform scale to weigh packages that are going to be shipped out. Another is the use of a drum scale to determine how much liquid remains to be dispensed from a tank that sits on the platform. Yet another is the use of a parts counting scale to count the number of parts in a container. And yet another is the use of a bench scale to batch ingredients that will be mixed together into a final product.
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In the first case, a scale operator could place the package on the platform of the electronic scale and determine its shipping weight. He could write down that value, and go the computer used in the shipping department to enter all of the pertinent information. This computer could print out a shipping label, and collect the information in a database table for later review.
Similarly, in the case of the drum scale, the operator could go to the location of the tank and observe the weight on the digital indicator. This value could then be written down, or simply noted. If necessary, the weight value could be brought back to a central computer for entry. If the weight value is lower than a pre-determined target weight, the scale operator could notify the proper people to arrange to replace the nearly empty tank with a new full one.
In the case of the parts counting scale and the bench scale, once again the operator could be responsible for reading the weight directly at the digital scale and then taking the correct action as determined by that weight value.
While these may be appropriate arrangements for very small operations, or where industrial scales are rarely used, it is quite clear that it is neither an efficient or easy way to obtain weight data. Furthermore, it is easy to understand that there can be errors introduced by manually handling the data. It would be much better to have some automatic means of collecting weight data and recording it.
Many industrial scales can be directly connected into computer systems. One of the most common methods is to simply connect a serial data interface on the scale into the computer. Application software on the computer accepts this data and uses it accordingly. It could place the weight directly into a shipping manifest. Or it could take multiple weight readings from a tank and record the weight value at specific times. The application can have target values that are compared to the weight remaining in the tank. When a low weight target is reached, for example, and alarm can be initiated to notify that some action must be taken. Other very equivalent methods for transmitting the weight data from the electronic scales can employ the USB (Universal Serial Bus) on the computer, or even make use of an Ethernet connection.
In all of the cases noted, the industrial scale must be in the same general location as the computer system. Serial data is usually transmitted by RS-232 protocol. This limits the length of cable that can be used to connect the scale and computer. USB has an even more severe limitation. Ethernet has a different set of distance specifications. A variety of different Ethernet options are available for extensively increasing the distance.
The ultimate data collection system is to use the Internet to transmit the data to any location desired. Unusually this will be coupled by some method of secure data transmission, so only those who have the correct password or security arrangement will be able to view the data. But there are a number of technical hurdles that must be dealt with. When an external internet source wishes to read data from an internal source, Local Area Networks will often employ a number of strategies to make certain that the request is valid, and that it does not inadvertently allow mis-use of the Internet connection. A firewall is a typical software or hardware device that is used to accomplish this. It may also be necessary to setup the Local Area Network with technical specifications so that it opens up the correct ports and addresses for this purpose.
A superior method is to use a central database system to be the recipient of the scale data. The scales can be pre-programmed with a specific Internet address to which it will send its data. Now, any Internet user with the correct password can use a browser to connect and use this data.
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