# Parameter passing

You can use parameter files or parameter lists to pass (carry forward) parameters from one display to other related displays that open from it. To carry the same parameter forward to subsequent displays, assign the same tag placeholder (for example, #1), instead of a tag name in the parameter list or parameter file field of the object in the related display.

## Example: Use a parameter list to replace tag placeholders in linked displays

This example uses PIDE faceplate displays to demonstrate parameter passing.

The main, or first level display, is called MAIN. It has a Goto display button that opens a Logix_PIDE faceplate display. The faceplate has a Goto display button that opens a Trend faceplate.

On the Main display, the Goto display button has the parameter list option on the General tab selected, and a structure tag name, with a shortcut, selected from the Tag Browser to represent #1: {::[PLC1] Program:Fermenter_Temp.Tank_PIDE01}, for example.

When the button is pressed, the Logix_PIDE faceplate opens. The objects on the faceplate have been set up to read the tags in the structure: #1.CV, #1.SP, and so on. The objects replace the parameter #1 with the structure tag name and then derive their values from the structure elements they have been set up to read.

To carry the same parameters forward another level, the Goto display button on the Logix_PIDE faceplate display has the parameter list option on its General tab selected, and the parameter {#1} typed in. When this button is pressed, the Trend faceplate opens, and its objects in turn replace their #1 parameters with the same structure tag name, and read their values from the appropriate elements.

## See also

Create parameter files

Create parameter lists

Causes of run-time errors for parameter files

Tag placeholders