C135 PCS 7 (PCS7)
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Disabling the Confirmation OK Button in SIMATIC PCS 7 Industry Library Faceplates

Disabling the Confirmation OK Button in SIMATIC PCS 7 Industry Library Faceplates

To disable the confirmation 'OK' button and enable rapid 2-step command execution in SIMATIC PCS 7 Industry Library (IL) faceplates, the resolution depends on the specific library flavor deployed. For 'IL for PCS 7' blocks conforming to Advanced Process Library (APL) standards, change the start value of internal WinCC tag @APLCommandExecutionSteps from 3 to 2 on all OS client workstations. However, for 'IL for S7' blocks (designed for S7-300 / Comfort Panels), command execution is hardcoded in proprietary C-scripts within the operational PDL (@PG_IL_*.pdl) that do not evaluate the @APLCommandExecutionSteps tag. For IL for S7, eliminating the OK button requires manually editing the faceplate C-action or migrating technological blocks to native IL for PCS 7.

Table of Contents

Executive Summary

Operator ergonomics and rapid response times are critical in industrial process control. In the SIMATIC PCS 7 Advanced Process Library (APL) and SIMATIC PCS 7 Industry Library (IL), technological faceplates support multi-step command confirmation to prevent accidental actuation of field equipment (such as starting a heavy pump or opening a chemical valve). The default standard is 3-step operation: 1) Select Object -> 2) Click Command (e.g. Open) -> 3) Click 'OK' in the execution area. However, operations teams frequently request streamlined 2-step operation (Clicking 'Open' executes immediately without requiring the redundant 'OK' click). While changing the internal WinCC tag @APLCommandExecutionSteps cleanly modifies APL blocks, engineers applying this change to Industry Library faceplates discover that the 'OK' button remains mandatory for certain blocks. This discrepancy arises from architectural divisions within the Industry Library. This technical guide details the root causes and provides implementation solutions.

Command Execution Models: 2-Step vs 3-Step Operation in PCS 7

The PCS 7 HMI framework supports two primary command execution workflows:

  • 3-Step Operation: Select block icon -> Click command button -> Click 'OK' confirmation button. Provides maximum protection against inadvertent touch or mouse clicks in safety-sensitive plants.
  • 2-Step Operation: Select block icon -> Click command button -> Command executes immediately. Eliminates operator fatigue and accelerates emergency intervention.

The APL Command Execution Tag: @APLCommandExecutionSteps

In native APL and IL for PCS 7, the operation area picture contains an object named cmnObj. The property StepOp is bound to the internal WinCC tag @APLCommandExecutionSteps:

  • If @APLCommandExecutionSteps = 3: The 'OK' button is visible and required.
  • If @APLCommandExecutionSteps = 2: The 'OK' button is invisible and bypassed; commands execute directly upon clicking.

Architectural Difference: 'IL for PCS 7' vs 'IL for S7'

The SIMATIC PCS 7 Industry Library is partitioned into two distinct product lines:

  1. Industry Library for PCS 7: Built natively upon APL design guidelines. Faceplates inherit APL typical scripts and respond fully to @APLCommandExecutionSteps.
  2. Industry Library for S7 (STEP 7 / Package Units): Developed for integrating SIMATIC S7-300 / S7-1500 controllers and Comfort Panels. The WinCC faceplates for these blocks utilize legacy C-scripts (@PG_IL_*.pdl) with hardcoded execution routines that do not link to @APLCommandExecutionSteps. Consequently, changing the tag has no effect on IL for S7 blocks.

Industry Library Faceplate Command Model Comparison

The following table compares command confirmation behavior across library families in PCS 7:

Library FamilyBlock ExamplesEvaluates @APLCommandExecutionStepsHow to Eliminate 'OK' ButtonRecommended Application ScopeAPL StandardMotL, VlvL, PIDConLYes (Native)Set @APLCommandExecutionSteps = 2Standard PCS 7 plant automation.IL for PCS 7VlvMotL, Aggr16, SplRangeYes (APL-Based)Set @APLCommandExecutionSteps = 2Complex APL-based industrial package units.IL for S7 (WinCC)S7_Mot, S7_Vlv, IL_S7300No (Hardcoded C-Script)Modify C-script in @PG_IL_*.pdlS7-300 / S7-1500 package unit skids.Classic LibraryMOTOR, VALVE (PCS 7 V6/V7)NoModify Faceplate Designer templatesLegacy plant migrations.

Step-by-Step Procedure to Enable 2-Step Execution

Method 1: Enabling 2-Step Operation for APL and IL for PCS 7

  1. Open the OS project in WinCC Explorer.
  2. In the navigation tree, click on Tag Management.
  3. Expand Internal Tags and select tag group APL.
  4. Locate internal tag @APLCommandExecutionSteps.
  5. Open its properties and change the Start value from 3 to 2.
  6. Repeat this change on all OS Client projects in the multiproject.
  7. Restart WinCC Runtime; confirm that clicking 'Open' or 'Close' executes immediately without the 'OK' button.

Method 2: Customizing Hardcoded C-Scripts in IL for S7 Faceplates

  1. Open WinCC Graphic Designer.
  2. Open the specific operation area picture (e.g. @PG_IL_Valve_Standard.pdl).
  3. Locate the button object for 'Open' or 'Close'.
  4. Inspect the mouse click C-action. Identify the script section where command writing is conditional upon the 'OK' confirmation variable.
  5. Modify the script to trigger the direct tag write function (SetTagBit) immediately upon mouse click.
  6. Set property Visible = No on the 'OK' button object.
  7. Save the picture in the project GraCS folder.

Verification

To verify that 2-step command execution functions properly:

  1. Tag Value Verification: In WinCC Runtime, open a Variable Table or Tag Status view. Confirm that @APLCommandExecutionSteps evaluates to 2.
  2. Faceplate Execution Test: Open a valve faceplate. Click the OPEN button. Confirm that the valve begins opening immediately without requiring an 'OK' button click.
  3. Visual Inspection: Verify that the 'OK' button is either completely hidden or disabled in the faceplate execution pane.

Limitations and Operational Precautions

  • Safety Considerations: Disabling the 'OK' confirmation button increases the probability of accidental operator commands. Never disable confirmation on safety-critical ESD or trip valves.
  • OS Client Scope: The @APLCommandExecutionSteps tag is an internal local tag; modifying it on the OS Server does not automatically update OS Clients. Set the start value on each physical client workstation.
  • Library Update Overwrite: Modifying standard system pictures (@PG_IL_*.pdl) manually can result in your changes being overwritten when upgrading the Industry Library or running OS Project Editor.

Engineer FAQ

Can @APLCommandExecutionSteps be configured with a value of 1?

No. Value 1 is not a valid setting; APL supports 2 (direct 2-step execution) and 3 (3-step confirmation with OK button).

Why does changing @APLCommandExecutionSteps on the server not affect the clients?

Internal tags prefixed with '@' are local to the running WinCC client instance; each client maintains its own independent internal tag cache.

Is it possible to have 2-step operation for valves but 3-step operation for large motors?

Yes, by customizing the block icon or faceplate script to dynamically toggle the StepOp property on a per-faceplate basis.

Technical References

Related Articles

Related Tags

  • https://industrialautomation.net/search?query=simatic-pcs7
  • https://industrialautomation.net/search?query=industry-library
  • https://industrialautomation.net/search?query=advanced-process-library
  • https://industrialautomation.net/search?query=faceplates
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