Indirect tag binding is a type of data binding available in FactoryPMI 3.0. It allows the designer to bind a component’s property to any number of tags using one or more layers of indirection. This lets one create templated components and parameterized windows. A templated component is a component or group of components whose data bindings are relative to some properties of the component. A parameterized window is similar, the difference being that the entire window’s contents are relative to a parameter that is passed into the window when it is opened. Indirect tag binding makes creating these components and windows a snap. All you need to do is bind to a tag, and then choose the part of the tag path that changes, replacing it with a value from a property in the window.
To demonstrate indirect tag binding, suppose we had a tank farm with four tanks. Each tank has some properties, like level and temperature. Each tank also has an outlet pump, that can be controlled from the screen and has amperage associated with it. Here is how the tag structure would look in the SQLTags browser:
"X"is replaced with 1-4. Let’s say we wanted all 4 tanks on the same screen. In this case we’ll set up a templated component, or rather, group of components. Put all the components you want to represent 1 tank in a container, like so:
"TankNum", and set its value to 1. Now modify each of the data bindings on the components’ properties from a direct tag binding like this:
"Tank1/Level."Then, remove the
"Tank1", and browse for your
"TankNum"dynamic property. That’s it – your binding is now indirect, and will point to whichever tank is indicated by the value of
"TankNum". Now all you need to do is copy and paste this container 4 times and change the value of
TankNumappropriately, to create a screen like this:
Creating a parameterized window is just as easy. The only trick is that the dynamic property
"TankNum" that controls the indirection for the bindings needs to be placed on the popup window’s Root Container. This lets you create a popup window like this:
"TankNum"parameter in the navigation action. In this way, one popup window can be used for a number of devices.
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