Configuring WinCC PAS CC Button for IEC 61850 Breaker Control

Overview

This reference explains how to wire a WinCC v6.0 SP4 graphical control button (running on a SICAM PAS CC configuration) to an IEC 61850 circuit breaker logical node using the standard double-command control object C_DC_NA_1 (Common Data Class DPC – Double Point Controllable, type identifier 46) and the single-point status with transient bit M_SP_TA_1 (CDC SPS with d-quality transient detection, type identifier 2). The solution described uses the legacy PAS internal C function PAS_Command_Integer_V500 bound to the Mouse Click event of a WinCC button, together with the IEC 61850 Select-Before-Operate (SBO) two-step control model required by most protection IEDs.

The same conceptual model also applies to the modern Siemens TIA Portal documentation for the WinCC Unified Button object, where the action handler is configured through the engineering interface rather than C scripting. The PAS-specific function calls in this article remain valid for SICAM PAS CC V5.00 / V5.10 and WinCC V6.0 SP4 projects.

Prerequisites

1. SICAM PAS CC V5.00 or V5.10 runtime installed and licensed on the HMI station, with the PAS CC – Configuration add-on.
2. WinCC V6.0 SP4 (or compatible SP5) development environment with a project connected to the same PAS database.
3. IEC 61850 IED data model already imported via SCL/ICD file; the controlled breaker logical node is exposed (e.g., CB_1 with Pos controllable double point and XCBR status).
4. The internal tag pointing to the command object exists in WinCC and is bound to the IEC 61850 data attribute Pos.ctlVal of the DPC instance. Verify with PAS UI Configuration → Tag Browser.
5. WinCC Global Script C editor enabled (Project Properties → Options → "Global Script Runtime" / "C-Script").
6. User authorization class with rights Operation – Switching assigned, otherwise the command is rejected by PAS security with qualifier object-not-selected.

IEC 61850 Control Object Reference

Per IEC 61850-7-2 §10.4, the SBO control model requires the client to first send a Select with Check, receive Select-+ with ctlVal mirrored, and then send Operate within the SBO timeout defined by the IED (default 30 s, configurable through Loc.stSeld or the CBOpCap settings).

Command Qualifiers (ctlModel / orCat / SBO)

The qualifier bits placed in ctlVal and the originator category determine which control model the IED will accept. For PAS CC the third parameter of PAS_Command_Integer_V500 encodes both the qualifier (SBO, Operate) and the originator category used for the LastAppAt timestamp.

The fourth parameter is the originator category (orCat) used for the Last-Application-At timestamp; in PAS the value 0 = not-supported, 1 = bay-control, 2 = station-control, 3 = remote-control, 4 = automatic-station, 5 = automatic-remote, 6 = maintenance, 7 = process. Use 2 for an HMI operator.

PAS_Command_Integer_V500 Function Reference

Function prototype exposed by SICAM PAS CC to the WinCC Global Script C runtime:

long PAS_Command_Integer_V500(
    LPCTSTR szTagName,
    long    nCommandValue,
    long    nCommandQualifier,
    long    nCheckFlag
);

Step-by-Step WinCC Button Configuration

Step 1 – Place the Button Object

1. In the WinCC Graphics Designer, open the picture that represents the single-line diagram of the bay.
2. Insert a new Button object from the standard palette (Object Palette → Windows Objects → Button).
3. Set the caption to e.g. CB1 – ON. Duplicate the button for the OFF command.
4. Note the configured Object Name (default: Button1, Button2) – required by the C action.

Step 2 – Bind the Status Indication Tag

1. Open the Property dialog of the button and select the Background Color or Flashing attribute.
2. Bind it to the internal tag that mirrors the IEC 61850 data object CB1_Pos_stVal (the value reported by the breaker auxiliary contact via the DPC stVal).
3. Typical mapping: 0 = intermediate (gray), 1 = OFF (green), 2 = ON (red), 3 = bad-data (yellow flash).

Step 3 – Add a Mouse-Click C Action

1. Select the ON button → Properties → Events → Mouse → Mouse Action (or "Mouse Click").
2. Choose "C-Action" instead of "Direct" or "Dynamic Dialog".
3. Paste the following C code. Replace CB1_Pos_ctlVal with your real tag name (right-click on the tag in the WinCC Tag Management and select "Copy Tag Name").

// ----- SBO SELECT (first step) -----
long lRet;
lRet = PAS_Command_Integer_V500("CB1_Pos_ctlVal.Value", 0, 4, 0);
if (lRet != 0)
{
    // Select failed, do not proceed
    printf("SBO Select failed, AddCause = %ld\r\n", lRet);
    return;
}
// ----- OPERATE (second step) -----
lRet = PAS_Command_Integer_V500("CB1_Pos_ctlVal.Value", 2, 14, 0);
if (lRet != 0)
{
    printf("Operate ON failed, AddCause = %ld\r\n", lRet);
}

For the OFF button, change the second call to command value 1:

Step 4 – Single-Step Variant (Direct-with-Normal-Security)

Some simple IEDs (e.g., a SIPROCESS busbar) accept the old "single-step" control model. In that case, replace the two calls with a single call:

// ON
PAS_Command_Integer_V500("CB1_Pos_ctlVal.Value", 2, 3, 0);
// OFF
PAS_Command_Integer_V500("CB1_Pos_ctlVal.Value", 1, 3, 0);

Qualifier 3 = direct-with-enhanced-security. The SBO first step is not required.

Step 5 – Add the Cancel Button (Optional)

During commissioning it is common to expose a Cancel button that aborts a pending SBO. PAS does not expose a dedicated PAS_CancelCommand; instead send an Operate with ctlVal=0 and qualifier 11:

Step 6 – Confirmation Dialog and Authorization

1. Right-click the ON button → Properties → Events → Mouse Action and prepend a call to SSMGetLevel / PWRTCheckPermission to verify the operator class.
2. If authorization is insufficient, return before calling PAS_Command_Integer_V500 and pop a message box via MessageBox (C runtime).

Verification and Commissioning

1. Compile the C action (Graphics Designer → File → Compile → C-Actions). The output window must show 0 errors, 0 warnings. If you see unresolved external for PAS_Command_Integer_V500, the PAS header is missing; in the C-Editor settings add %PAS_PATH%\include and link against PAScmd.lib.
2. Activate WinCC Runtime. Open the picture; the status field should reflect the current stVal from M_SP_TA_1 / DPC.stVal.
3. Click the ON button. Within 1 s the breaker should close. The internal stVal of the DPC object becomes 2 (ON).
4. Click the OFF button. Breaker opens, stVal becomes 1 (OFF).
5. Verify the SBO timeout: do Select only (i.e., simulate a single call with qualifier 4) and wait 35 s. The IED will release the reservation; the next Operate will return AddCause object-not-selected (1).
6. Open the PAS Message List and confirm a Command Operation entry with the configured orCat and orIdent.

Mapping Table – IEC 61850 ↔ PAS Function Call

Troubleshooting Matrix

Migrating to WinCC Unified (TIA Portal V20)

If the same functionality must be reproduced in a modern TIA Portal project, the C scripting layer is replaced by the WinCC Unified Button object. Configuration steps:

1. Insert a Button in the Unified screen.
2. Open Properties → Events → Click.
3. Add a system function or JavaScript action that calls the IEC 60870-5-104 / IEC 61850 command function block exposed by the HMI tag connection.
4. Under Security define the required operator authorization level.

The conceptual mapping is identical: Click → SelectWithValue → Operate, with the same ctlVal encoding (0/1/2/3) and the same AddCause handling. The Unified runtime exposes the AddCause code in the system tag LastError of the command connection.

Field-Proven Cautions

• Always re-issue a Select before Operate; do not rely on the IED retaining the SBO reservation across long script sequences (network round-trip, GC pause, etc.).
• Do not embed MessageBox in the same C-action that fires the command – it can stall the MMS thread and cause PAS to drop the report. Use a separate trigger tag to flash an alarm on failure.
• When two operators click simultaneously, PAS arbitrates via the tag reservation mechanism. The losing client receives AddCause object-already-selected (10).
• Configure cbOpCap.stSeld visualization on the button to show whether a tag is currently selected – this prevents ambiguous operation.
• In multi-monitor stations, scope the tag name to the project prefix; the same picture opened on a redundant server may otherwise use the wrong tag.

Glossary of Acronyms