Setting WinCC Analog Input Faceplate Position in PCS 7

Overview

In a Siemens PCS 7 OS runtime, an analog input I/O field opened by the standard block icon or by openfaceplateV6() triggers a child picture (the faceplate or RawAnalogInput dialog) that the OS host places using internal defaults. On multi-monitor installations, on touch panels with limited resolution, or when the parent picture is anchored near the bottom of the screen, the dialog can appear underneath the I/O field, off-screen, or hidden behind another window. This forces the operator to either drag the dialog into view, scroll the parent picture, or resize the OS window before the parameter can be edited.

This reference covers four field-proven methods to control where the analog input dialog opens in PCS 7 V7.1 SP1 and later V8.x/V9.x projects:

1. Setting the Default Position property on the APL block icon instance (recommended, lowest risk).
2. Overriding the dialog position with C functions SetLeft() and SetTop() inside a project-wide C action.
3. Replacing the C action with an equivalent VBScript using objScreenItems positioning properties.
4. Activating the Adapt Picture runtime option so the OS workspace auto-resizes the dialog to fit the visible area.

All four approaches are compatible with the PCS 7 OS authorization model and operate without modifying Siemens-delivered standard scripts.

Prerequisites

Verify that the OS runtime is fully started and that the faceplate you intend to relocate is the standard APL faceplate (not a customized variant) before changing scripts. Customized faceplates store their own Open position logic in OpenFaceplate callbacks and override global changes.

WinCC Faceplate Architecture

The analog input dialog originates from the standard APL block CH_AI (or MOT_SPEED, CTRL_PID, depending on the signal class). When the operator clicks an I/O field, the block icon dispatches the C function openfaceplateV6(). The function inspects the source object name, looks up the matching faceplate type in the FaceplateDesigner registry, and instantiates a child picture window at the default screen origin.

The openfaceplateV6() implementation is located in the project-level C script set, under Project Functions > Standard Functions > openfaceplateV6. The body of this function is normally inherited from the APL master and should not be edited. To control position you must intervene either:

• before the call returns (wrap the call in your own C action), or
• by setting per-instance defaults on the block icon itself.

#include "apdefap.h"
void OnClick(char* lpszPictureName, char* lpszObjectName, char* lpszPropertyName)
{
    BOOL  bOperation5;
    char* lpszTag;
    char* lpszStructureIdentifier;

    // Extract the tag linked to the I/O field
    lpszTag = GetLinkedVariable(lpszPictureName, lpszObjectName, "Tag");

    // If the tag is part of a structure, enforce operator authorization
    lpszStructureIdentifier = strstr(lpszTag, ".");
    if (lpszStructureIdentifier)
    {
        bOperation5 = PCS7_CheckPermission(lpszTag, 5);
        if (!bOperation5)
        {
            MessageBox(NULL,
                       "Error: User does not have authorization to edit this tag value.",
                       "Error",
                       MB_OK|MB_ICONEXCLAMATION|MB_SETFOREGROUND|MB_SYSTEMMODAL);
            return;
        }
    }

    // Standard APL call to open the Raw Analog Input dialog
    Common_OpenRawAnalogInput(lpszPictureName, lpszObjectName);
}

The functions referenced are part of the PCS 7 project API; their declarations are auto-generated when WinCC compiles the project. GetLinkedVariable reads the configured tag from the picture object; PCS7_CheckPermission evaluates WinCC User Administrator rights for the configured area (here, operation level 5).

Approach 1: Per-Instance Default Position on the APL Block Icon

This is the cleanest solution because it does not require any script modification. The APL block icon exposes a Position property group:

Steps:

1. Open the picture containing the I/O field in Graphics Designer.
2. Double-click the I/O field to open its configuration dialog.
3. Switch to the Block Icon tab (the tab name varies between APL versions: Properties in V7.1, Block Icon in V8.x/V9.x).
4. Set Use default position to No.
5. Enter Position X and Position Y in pixels. Coordinates are relative to the picture origin (0,0 = top-left of the parent picture).
6. Compile and download the OS.

Approach 2: Override Position with C Functions SetLeft and SetTop

When the I/O fields are positioned dynamically at runtime (for example, by a layout script that arranges control groups based on the picture size), per-instance defaults cannot cover every case. The C functions SetLeft and SetTop reposition the dialog after Common_OpenRawAnalogInput returns. Because the dialog is a child picture window, the position is enforced on the picture object rather than on the faceplate type.

Replace the body of Common_OpenRawAnalogInput (or the original OnClick action) with:

#include "apdefap.h"

void OnClick(char* lpszPictureName, char* lpszObjectName, char* lpszPropertyName)
{
    BOOL  bOperation5;
    char* lpszTag;
    char* lpszStructureIdentifier;

    lpszTag = GetLinkedVariable(lpszPictureName, lpszObjectName, "Tag");
    lpszStructureIdentifier = strstr(lpszTag, ".");
    if (lpszStructureIdentifier)
    {
        bOperation5 = PCS7_CheckPermission(lpszTag, 5);
        if (!bOperation5)
        {
            MessageBox(NULL,
                       "Error: User does not have authorization to edit this tag value.",
                       "Error",
                       MB_OK|MB_ICONEXCLAMATION|MB_SETFOREGROUND|MB_SYSTEMMODAL);
            return;
        }
    }

    // Open the standard Raw Analog Input dialog
    Common_OpenRawAnalogInput(lpszPictureName, lpszObjectName);

    // Reposition the dialog 200 px from left, 150 px from top
    // Adjust lTop / lLeft for your screen geometry
    long lLeft = 200;
    long lTop  = 150;
    SetLeft(lpszPictureName, lpszObjectName, lLeft);   // return BOOL
    SetTop(lpszPictureName, lpszObjectName,  lTop);    // return BOOL
}

Function signatures per the WinCC scripting reference:

The position values are in screen pixels of the OS runtime window. If the OS is configured for a 1920x1080 panel, lTop = 150 places the dialog 150 px below the workspace top. To anchor relative to the parent I/O field instead of the screen, calculate the offset using GetLeft and GetTop:

long lOriginX = GetLeft(lpszPictureName, lpszObjectName);
long lOriginY = GetTop(lpszPictureName, lpszObjectName);
SetLeft(lpszPictureName, lpszObjectName, lOriginX - 200);
SetTop(lpszPictureName, lpszObjectName,  lOriginY - 150);

Approach 3: VBScript Equivalent

Projects migrated from C to VBS (default in PCS 7 V8.2+) need a VBScript equivalent. Use HMIRuntime.Screens and ScreenItems for the dialog:

Sub OnClick(ByVal Item)
    Dim lpszTag
    Dim bAuth
    lpszTag = Item.GetLinkedVariable("Tag")

    ' Authorization check for structured tags
    If InStr(lpszTag, ".") > 0 Then
        bAuth = PCS7_CheckPermission(lpszTag, 5)
        If Not bAuth Then
            MsgBox "Error: User does not have authorization to edit this tag value.", _
                   vbExclamation + vbSystemModal, "Error"
            Exit Sub
        End If
    End If

    ' Open standard dialog
    Common_OpenRawAnalogInput Item.Parent.Parent.PictureName, Item.ObjectName

    ' Reposition the dialog window
    Dim dlg
    Set dlg = HMIRuntime.Screens(Item.Parent.Parent.PictureName).ScreenItems(Item.ObjectName)
    dlg.Left = 200
    dlg.Top  = 150
End Sub

VBScript exposes .Left, .Top, .Width, .Height directly as properties. Numeric values are in pixels. The Item.ObjectName resolves to the same object referenced by the C function, so the dialog can be moved as soon as the standard call returns.

Approach 4: Adapt Picture Runtime Setting

Activating Adapt Picture instructs the WinCC runtime to scale the entire workspace picture to the OS window client area. The analog input dialog, being a child picture, is then scaled automatically, removing the need for fixed pixel coordinates. Configuration path:

1. In WinCC Explorer on the OS, right-click the OS server node and choose Properties.
2. Open the Startup tab (or Runtime in V8.x).
3. Enable the option Adapt picture to window size.
4. Also enable Adapt to screen resolution under Computer properties > Graphics.
5. Restart the OS runtime.

Adapt Picture is a global setting and affects every picture in the project. Use it only when the OS target resolution is unknown at engineering time or when the project will be deployed to multiple panel sizes.

Implementation Procedure

1. Identify the analog input source. Use WinCC Information System (Tools > Cross References) to locate every instance of the I/O field that calls Common_OpenRawAnalogInput.
2. Choose the approach. Per-instance default for static layouts; SetLeft/SetTop for dynamic; VBS for new projects; Adapt Picture for variable-resolution panels.
3. Edit the action. In Graphics Designer, double-click the I/O field, switch to the Events tab, and replace the Click action. Use the project function path (not the master data library) to avoid changes being overwritten on OS download.
4. Recompile the OS. Open the OS Project Editor and run Compile OS > All. Watch for C compile errors in the diagnostic output.
5. Download to the OS target. Use OS Download > Complete download for the first change; delta download is sufficient thereafter.
6. Verify in runtime. Click each I/O field. The dialog should open at the configured coordinates and remain visible without scrolling.

Verification

Add the modified action to your project regression checklist so future APL library updates do not silently revert it.

Troubleshooting Matrix

Best Practices

• Prefer per-instance default positions over global C edits; they survive APL library upgrades.
• Always keep the authorization block at the top of any OnClick action; it is mandatory for structured tags in PCS 7.
• Document any custom positioning in the project quality log so commissioning engineers can locate it.
• Avoid hard-coded coordinates when the OS targets multiple resolutions; pair SetLeft/SetTop with Adapt Picture for portability.
• Re-test every change on a 1080p panel and a 4K panel before signing off the OS download.

Related Standards and Documentation

For further verification of operator authorization levels and the WinCC scripting API, refer to the official Siemens documentation set:

• Siemens Industry Online Support
• SIMATIC PCS 7 OS Configuration Manual
• WinCC Scripting: C and VBS Reference