Tags

Tags are the building blocks of any VTS application. Tags are software components that represent equipment and equipment processes in your physical system (i.e. pumps, motors, fans, tanks, and their status (on or off), mode (auto or manual), value, etc.).  Tags also are used to represent the port and the driver used to communicate with the equipment, and even the computer upon which VTS is running.

Several tags might be used to represent different processes for a single piece of equipment. For example, one pump might have a tag that reads the status of the pump (on or off), a second tag that allows you to see the speed of the pump, and an additional tag that enables you to send a signal to the pump to turn it on or off.

The image below displays an example of the physical system and the arrangement of tags in the related VTS application.

 

In order for VTS to emulate a physical system, several different types of tags are required. As you can see from the above image, there are analog tags to read analog (continuous) values, digital tags to read digital (discrete) values, and driver and serial port tags to facilitate communication between VTS and the equipment. There may even be tags that have been custom-built for your application.

While you need not become familiar with all the tag types, you will find it helpful to be able to recognize a few of the standard types that might be used in your application. The next chapter describes some of the most commonly used tags.