Opening Custom Block Faceplates from PCS 7 mot_l APL Blocks

Overview: Custom Block Faceplate Integration in PCS 7 APL V8.0

SIMATIC PCS 7 V8.0 with the Advanced Process Library (APL) V8.0 exposes a standardized faceplate for every channel, motor, valve, and analog block type shipped with the library. When you build a custom calculation block — for example, a power-consumption aggregator that derives kW and integrates kWh from one or more ch_ai inputs — you must reproduce the same picture-set conventions used by the standard APL blocks if you want the operator to open that faceplate from the same SelFaceplate1 input wired through a mot_l motor block or any other APL icon family that carries a faceplate button.

This reference documents the picture naming, block-icon registration, WinCC compile sequence, and verification steps required to make a custom block's faceplate open when the operator presses the faceplate button on a mot_l instance, or on any APL block icon derived from @@PCS7Typicals.PDL. It also covers the most common failure modes observed during commissioning of PCS 7 V8.0 SP1 with APL V8.0 SP1 (build 8.0.2.10) and notes the migration impact for PCS 7 V9.0/V9.1 and TIA-Portal-based PCS 7 V10.

Prerequisites and Software Stack

Reference documentation (download from the Siemens Industry Online Support portal):

• Manual SIMATIC PCS 7 V8.0 - Documentation Bundle: PCS 7 V8.0 documentation
• Manual PCS 7 - Operator Station - Configuring Faceplates: WinCC faceplate configuration
• APL block-icon source archive: PCS 7 APL V8.0 block icons (PCS7Typicals.PDL)
• WinCC Openness reference for faceplate importing: TIA Portal Openness: Importing a screen with a faceplate instance
• APL Style Guide Edition 2013: PCS 7 APL Style Guide V8.0

PCS 7 APL Block Architecture and Faceplate Naming

Each APL block type is associated with a fixed picture set in the WinCC picture tree. The canonical naming convention is:

The WinCC runtime resolves @PG_<blockname>_Standard.pdl at the moment the operator clicks the faceplate button. The block icon carries the dynamic property PictureName, normally populated by the CFC OS compiler from the block type's HMI attributes. For a custom block the engineer must populate this property at compile time, which is why the picture file must exist in the active WinCC project before the OS compile step. The runtime then maps the dynamic property to the PictureName attribute of the picture-window object embedded in the faceplate trigger button.

The block icons for the standard library live in @@PCS7Typicals.PDL. The C-action attached to the faceplate button in those icons is conceptually:

When the operator clicks the button, WinCC reads the BlockType property of the icon and calls OpenFaceplate(). The runtime substitutes BlockType with the actual type name and looks for @PG_<BlockType>_Standard.pdl. If that PDL does not exist, the click event is silently discarded (with a debug log entry), which is the most common symptom reported when a custom faceplate does not open from the mot_l button.

Understanding the SelFaceplate1 Input Structure

The SelFaceplate1 input of an APL block is a structured UDT (User Defined Type) with the following members:

When you connect an output of a custom block to the SelFaceplate1 input of a mot_l instance, the CFC compiler populates the UDT from the connected block's HMI attributes. Only the value subfield is wired by an actual data connection; the PictureName subfield is filled at compile time from the BlockType attribute of the custom block.

The SelFaceplate2 input (where present) follows the same structure and is used for a secondary faceplate (for example, an additional detail view of a complex block). For a power-consumption block, only SelFaceplate1 is normally used.

Custom Block APL Style Guide Compliance

Before authoring the faceplate, the custom block itself must satisfy the APL Style Guide. The non-negotiable attributes are:

Add the attributes via the block's Object Properties → Attributes tab in the CFC editor or directly in the SCL source. Sample SCL attribute declaration:

Step-by-Step: Build the Custom Block in the CFC/SFC Editor

1. Open the master data library in the CFC editor (View → Library).
2. Insert a new SCL source FB_PowerCalc in the Blocks container, family PowerCalc.
3. Declare inputs PT_Primary (REAL, kW), PF_Factor (REAL, default 1.0), and outputs PWR_kW (REAL), PWR_kWh (REAL, integrating), PWR_Status (WORD).
4. In the FB body, add the calculation logic:

   
   PWR_kW := PT_Primary * PF_Factor;
   IF PWR_kWh_running THEN
       PWR_kWh := PWR_kWh + (PWR_kW * CYCLE_TIME / 3600.0);
   END_IF;
   PWR_Status.0 := (PWR_kW > PWR_Max);
   PWR_Status.1 := (PT_Primary < 0.0);
   

   where CYCLE_TIME is the OB35 cycle (default 1000 ms = 1 s on PCS 7). For longer OB35 cycles, scale accordingly.
5. Apply the HMI attributes from the table above. Confirm with right-click → Special Object Properties → HMI that every variable intended for operator display shows up under "Operator Control and Monitoring".
6. Compile FB_PowerCalc to a CFC block type and place it on the chart PWR_AGGREGATE_01.
7. Wire the motor's PWR_kW from this instance to SelFaceplate1 input of the same mot_l instance if you want the operator to open the power faceplate from the motor block icon. The motor block's SelFaceplate1 input is of type STRUCT with subfields Visible and PictureName; the CFC compiler populates PictureName from the connected block's BlockType attribute automatically.
8. Save and close the chart.

Step-by-Step: Author the Faceplate Picture Set

The picture set must be created in the WinCC Graphics Designer before the OS compile step, otherwise the icon cannot resolve @PG_PowerCalc_Standard.pdl.

1. In WinCC Explorer, navigate to Graphics Designer → Project Pictures.
2. Right-click and select New Picture; name it @PG_PowerCalc.pdl. Set Start Picture = false and Apply Project Color Scheme = true.
3. Open the new picture and lay out the standard faceplate template:
   • Header bar with block tag name (dynamize via tag prefix property PictureWindow.TagPrefix).
   • Process value fields for PWR_kW, PWR_kWh (I/O field with output-only via OutputValue property).
   • Limits area with bar graph from 0 to PWR_Max (configure in Tag dialog as Bar representation, fill direction bottom-to-top).
   • Eight function buttons (Standard, Message, Limits, Trend, Parameter, Batch, Faceplate-1, Faceplate-2). For a calculation block, only Standard + Trend + Faceplate-1 are normally wired.
4. Save the picture as @PG_PowerCalc_Standard.pdl. The picture file must exist in the active project before the next OS compile; do not save it under a different name or with leading spaces.
5. Duplicate the picture for each additional view (@PG_PowerCalc_Trend.pdl, @PG_PowerCalc_Limits.pdl, etc.).
6. Verify in WinCC Explorer that all six files are listed under Project Pictures. Reopen each, check Properties → Window Attributes: Start Picture must be false; Adapt Picture = no; Border = dialog with caption.

Step-by-Step: Wire SelFaceplate1 and Register the Block Icon

Two artefacts must be in place for the faceplate to open:

1. Picture file exists: @PG_PowerCalc_Standard.pdl (case sensitive) must reside in the WinCC project.
2. Block icon calls OpenFaceplate(): The block icon on the process picture must invoke the WinCC internal function with the correct BlockType string.

The APL block-icon family in @@PCS7Typicals.PDL already implements the call. To reuse the icon for a custom block:

1. Open @@PCS7Typicals.PDL from the project library (read-only copy). Identify the icon closest to your block — for a power aggregator pick the analog-input block icon APL_AI_Icon.
2. Duplicate the icon into the project-specific picture set (drag-and-drop while holding Ctrl).
3. Open the duplicate, change the dynamic property PictureName from the default to @PG_PowerCalc_Standard.pdl.
4. Confirm the C-action on the faceplate button reads: OpenFaceplate("PowerCalc", GetPropChar(lpszPictureName, "BlockType")); Replace the literal "PowerCalc" with the exact BlockType attribute from your custom FB; the string is case-sensitive and must match the basename of the PDL (without the leading @PG_ prefix and trailing _Standard.pdl suffix).
5. On the mot_l instance that you want to drive, navigate to Object Properties → I/Os. Set the input SelFaceplate1 to point to the output of the PowerCalc instance via CFC interconnection; do not write the picture name manually in WinCC, because the OS compile regenerates the value from BlockType.
6. Save the picture and the CFC chart.

Step-by-Step: Compile OS and Load Runtime

1. Open the OS project in WinCC Explorer and run OS Compile from the SIMATIC Manager toolbar. Confirm the OS server selection and check the box Generate block icons from CFC.
2. Open the OS log after compile. Look for lines such as:

   
   INFO  Block icon: PowerCalc → @PG_PowerCalc_Standard.pdl (resolved)
   WARN  Block icon: PowerCalc → @PG_PowerCalc_Standard.pdl (NOT FOUND)
   

   A NOT FOUND warning indicates the picture file is in the wrong directory or has a typo in its name.
3. Run OS Project Editor and OS Download to push the project to the OS server.
4. Activate runtime, open the picture containing the mot_l icon, and click the faceplate button.

Verification Procedure

Use this checklist to confirm the custom faceplate opens as expected from both the motor block icon and the custom block icon.

1. In the process picture, click the faceplate button on the mot_l block icon. The @PG_PowerCalc_Standard.pdl faceplate opens. If a generic APL faceplate opens, the SelFaceplate1 interconnection is not yet propagated; rebuild the CFC.
2. Click the faceplate button on the PowerCalc block icon directly. The same faceplate opens.
3. Verify the tag prefix in the faceplate header matches the actual instance tag, e.g. PWR_AGGREGATE_01/PowerCalc. A wrong prefix indicates the block's I/O names were renamed after compile.
4. Generate an acknowledgment by clicking the standard faceplate's Acknowledge button; a confirmation event should appear in the Alarm Line.
5. Press Ctrl+F5 in WinCC Explorer to inspect Diagnostics → PDL Cache and confirm the file @PG_PowerCalc_Standard.PDL was loaded into the runtime cache.
6. Toggle the operator user to a higher authorization level (level 5 or above) and confirm that write operations on the faceplate are accepted.
7. Switch the operator language to a non-default (e.g. German) and verify all text fields render correctly. Re-run Text Library → Compile if any text shows the source identifier instead of the translated string.

Troubleshooting Matrix

Naming Convention Reference

The WinCC runtime resolves faceplate names through a series of substitution rules. Memorize the canonical pattern:

Block Icon Script Reference

The WinCC C-action attached to the faceplate button of every standard APL block icon is functionally equivalent to the following VBScript snippet, which can be embedded in custom icons via the Event → Mouse → Click tab:

Sub OnLButtonDown(ByVal Item, ByVal nFlags, ByVal x, ByVal y)
    Dim sBlockType
    sBlockType = GetPropChar(Item.LpszPictureName, "BlockType")
    If Len(sBlockType) > 0 Then
        OpenFaceplate(sBlockType, Item.LpszPictureName)
    End If
End Sub

You can also invoke the faceplate from a button in C-script directly:

{
    char szType[64];
    strcpy(szType, GetPropChar(lpszPictureName, "BlockType"));
    OpenFaceplate(szType, lpszPictureName);
}

If you want to open a faceplate from a non-APL icon (a regular WinCC picture window), populate the picture window's PictureName property with the full PDL string, e.g. @PG_PowerCalc_Standard.pdl, and set AdaptSize = 1 so the picture window snaps to the 100 × 50 (or 100 × 100) standard size.

Sample Complete Power-Consumption Block (SCL)

The following SCL source illustrates a fully APL-compliant power-consumption block. It demonstrates the HMI attributes, the integrating logic, and the alarm-class binding needed for the faceplate to integrate correctly with mot_l.

FUNCTION_BLOCK FB_PowerCalc
TITLE  = 'Power Consumption Calculator'
VERSION : '1.0.0'
AUTHOR  : eng
FAMILY  : PowerCalc
{ S7_m_c := 'true'; S7_alarm_8 := 'true'; BlockType := 'PowerCalc'; S7_shortcut := 'PWR' }

VAR_INPUT
    PT_Primary   : REAL  := 0.0;    // Primary power (kW)
    PF_Factor    : REAL  := 1.0;    // Power factor multiplier
    PWR_Max      : REAL  := 1000.0; // Maximum expected (kW)
    CYCLE_TIME   : REAL  := 1.0;    // OB35 cycle time (s)
    Reset_kWh    : BOOL  := FALSE;  // Operator reset
END_VAR

VAR_OUTPUT
    PWR_kW       : REAL;            // Instantaneous power (kW)
    PWR_kWh      : REAL;            // Integrated energy (kWh)
    PWR_Status   : WORD;            // Bit 0: overload, bit 1: under-range
END_VAR

VAR
    fbIntegrate  : INTEGRATE;       // PCS 7 standard integrator FB
END_VAR

BEGIN
    PWR_kW := PT_Primary * PF_Factor;

    IF Reset_kWh THEN
        PWR_kWh := 0.0;
    ELSE
        PWR_kWh := PWR_kWh + (PWR_kW * CYCLE_TIME / 3600.0);
    END_IF;

    PWR_Status.0 := (PWR_kW > PWR_Max);
    PWR_Status.1 := (PT_Primary < 0.0);

    // Alarm-class binding — required for S7_m_c = true
    IF PWR_Status.0 THEN
        // Raise MSG_CLASS = "PWR_HIGH"
    END_IF;
END_FUNCTION_BLOCK

After compiling this block, verify that the HMI export contains entries for PWR_kW, PWR_kWh, PWR_Max, Reset_kWh, and PWR_Status. The exported XML file resides in the CFC project under Generated\HMI\BlockTypes\PowerCalc.xml.

Multilingual Faceplate Considerations

PCS 7 faceplates support up to 32 operator languages through the WinCC Text Library. When you author a custom faceplate:

1. Every visible string must be wrapped in a text-library entry. Do not embed raw text in the PDL.
2. Create one text-library entry per language per string. The default language is the one shipped with the project template.
3. After modifying text, run Text Library → Compile All and download to the OS server. Without a recompile, text fields display the source identifier such as @PWR_AGGREGATE_01.PWR_kW.
4. Verify on the runtime by switching the operator language in User Administrator → Operator → Language.

Performance and License Considerations

Each unique faceplate type loaded in runtime consumes one faceplate license count, regardless of how many instances are open simultaneously. The standard PCS 7 V8.0 SP1 RT license grants 256 faceplate instances per OS server; PCS 7 V8.0 SP2 raises this to 512. Each add-on picture (_Add_1 … _Add_5) is a separate faceplate type and counts independently.

For plants with hundreds of custom blocks, batch the custom-block compilation and audit the OS server's faceplate count with the WinCC Performance Monitor to avoid reaching the licensed ceiling during a major process upset when every operator may open multiple faceplates at once.

Diagnostic Tools and Log Files

Migration Notes and Compatibility

When migrating from PCS 7 V8.x to V9.0 / V9.1 the picture naming is unchanged, but two settings are now strictly enforced:

• The HMI attribute S7_shortcut is required for every operator input. Without it, the OS compile issues error 0xE0150018 ("attribute missing") and aborts the icon generation.
• The new "APL+" type system in V9.0 expects the picture file to declare a Version property in the PDL header. V8.0 PDLs continue to work, but V9.0 will log a deprecation warning to WinCC_Sys.log until you re-save the PDL.

When migrating custom blocks created for the classic APL (PCS 7 V7.1 and earlier), the picture files used the older @PG_*.pdl pattern with no _Standard suffix. The V8.0 runtime still supports these, but the faceplate button on mot_l in modern libraries always routes to the _Standard variant, so any pre-V8.0 faceplate must be renamed to keep the click working.

For customers moving to TIA Portal-based PCS 7 (V18 / V19 with PCS 7 V10), the same OpenFaceplate() API is preserved in WinCC Unified but the syntax changes to UI.OpenFaceplateInWindow(...). Existing custom PDLs need to be re-authored in the Unified graphics designer because the .pdl file format is replaced by .svg plus a JSON manifest.

Security and Audit Trail

Every faceplate open is logged in the WinCC Audit trail when the project has the optional PCS 7 Audit component installed. The audit entry includes the operator's user ID, timestamp, block tag name, and faceplate name. Operator authorization level 6 ("Process controlling — level 6") is required to modify PWR_kWh reset values; configure this in User Administrator → Authorization Levels.

FAQ