Mass Inverting Block Input Connections in SIMATIC PCS 7 Process Object View (POV) Using Inversion Prefix (~-~)

In SIMATIC PCS 7 Process Object View (POV), bulk inverting Boolean feedback signals across hundreds of channel driver blocks (such as Pcs7DiIn or MotL FbkClose inputs) without opening individual CFC charts is accomplished by filtering target input pins in the 'Parameters' or 'Signals' tab and prefixing the connection path string with the tilde-minus syntax ('~-~'). In PCS 7 CFC database notation, '~-~' represents logical inversion of an interconnected Boolean signal. By selecting the connection column in POV, copying the column into Microsoft Excel, prepending '~-~' to all paths, and pasting back into POV, engineers invert hundreds of field signals in a single operation.

Process Object View (POV) Architecture and Mass Engineering

In large-scale SIMATIC PCS 7 engineering projects encompassing thousands of process tags, opening and editing individual CFC charts manually is prohibitively slow and prone to human error. Process Object View (POV) provides a spreadsheet-like engineering interface:
- Tabbed Relational Data:
* Displays all plant components across dedicated tabs: General, Parameters, Signals, Messages, Picture Objects, and Archive Tags.
* Allows tabular editing, sorting, filtering, and bulk parameterization.
- The Challenge of Bulk Signal Inversion:
* During commissioning, instrument piping changes or normally-closed (NC) versus normally-open (NO) valve limit switch discrepancies frequently require inverting feedback signals (e.g. FbkOpen, FbkClose, or driver PV_In).
* While users often search for a dedicated 'Invert' checkbox column in POV, PCS 7 encapsulates inversion directly within the interconnection path string.

The Syntax of Signal Inversion in CFC Interconnections

In the CFC graphical editor, clicking the small inversion circle on an interconnected input pin negates the Boolean value before evaluation. Within the underlying STEP 7 database:
- Standard Connection String:
text Chart_Name\Block_Name.Output_Pin
(e.g. NK121\LowactFbkClose.Out)
- Inverted Connection String:
text ~-~Chart_Name\Block_Name.Output_Pin
(e.g. ~-~NK121\LowactFbkClose.Out)
- The Meaning of ~-~:
* The leading tilde (~) denotes an internal system connection attribute.
* The minus sign (-) designates mathematical/logical negation (NOT).
* When POV writes this string into the chart container database, the CFC compiler automatically renders the solid inversion dot on the input pin.

Step-by-Step Mass Inversion Workflow via Process Object View and Excel

Follow this procedure to invert hundreds of feedback connections simultaneously:

Open Process Object View:
- In SIMATIC Manager, select the target plant area or project root.
- Select View > Process Objects (or press Ctrl + 4).
Filter Target I/O Parameters:
- Navigate to the Parameters tab.
- Right-click anywhere in the table and select Process Objects > Select I/Os....
- In the selection dialog:
- Filter by Block Type: e.g. Pcs7DiIn or VlvL.
- Filter by I/O Name: e.g. PV_In, FbkOpen, or FbkClose.
- Click OK.
- The table filters to show exclusively the target input parameters across all charts.
Export and Modify Connection Paths in Excel:
- Select the entire Connection column in the POV table.
- Press Ctrl + C to copy.
- Open Microsoft Excel and paste into Column A.
- In Column B, enter the formula to prepend ~-~:
excel ="~-~" & A1
- Drag the formula down across all rows.
- Select Column B, copy, and Paste Values to remove formulas.
Paste Back into Process Object View:
- In POV, select the top row of the Connection column.
- Press Ctrl + V to paste the modified connection strings.
- Press Enter. POV updates all chart connections instantly.
Compile and Download Changes:
- In SIMATIC Manager, execute Compile Charts > Changes Only.
- Execute Download > Changes in RUN to the S7-400 CPU.

CFC Connection Prefix and Modifier Syntax Table

The following table details connection string modifiers supported in Process Object View:

Connection String SyntaxCFC Graphical RepresentationLogical / Functional ResultApplicable Data TypesChart1\Block1.OutStandard line connectionDirect pass-through (A = B)All types (BOOL, REAL, INT)~-~Chart1\Block1.OutInversion dot on input pinLogical Inversion (A = NOT B)BOOL exclusivelyPIW 512Peripheral input textDirect peripheral readINT, WORD, BYTEPQW 512Peripheral output textDirect peripheral writeINT, WORD, BYTE(Empty / blank)Pin unconnectedReverts to static default valueAll types

Verification

To confirm that the mass inversion executed successfully:
1. Open any of the affected CFC charts in the CFC Editor.
2. Inspect the modified block input pin (e.g. FbkClose): verify that a solid black inversion dot is clearly visible at the junction between the connection line and the pin.
3. Switch CFC to Test Mode (Ctrl + T):
- When the upstream feedback source is 0, verify that the inverted input reads 1.
- When the upstream feedback source is 1, verify that the inverted input reads 0.
4. Verify that the valve faceplate in WinCC Runtime reflects correct open/closed status matching physical plant limit switches.

Limitations and Operational Precautions

When bulk-editing connections in Process Object View:
1. Never Apply Inversion Syntax to Non-Boolean Types: Applying ~-~ to analog REAL or integer INT connections causes compilation syntax errors. The inversion prefix is valid strictly for Boolean BOOL connections.
2. Pilot Test Required: Always test bulk string manipulations on a small sample chart container before applying changes across hundreds of production tags.
3. Download in RUN Capability: Modifying connection inversions supports Download Changes in RUN to the CPU, ensuring zero interruption to active plant production.

Engineer FAQ

Can I use Process Object View 'Free Columns' to define custom attributes?

No. Free Columns in POV are informational user text fields used for engineering notes or customer tag IDs. They cannot alter internal compiler logic or connection properties.

What happens if a connection already has '~-~' and I prepend it again?

Prepending ~-~ to an already inverted string results in ~-~~-~..., which the CFC parser rejects as an invalid syntax error. Ensure your Excel formula targets only non-inverted strings.

How do I remove an inversion across hundreds of blocks in POV?

In Excel, use the Find and Replace tool (Ctrl + H) to replace ~-~ with nothing (blank), then paste the cleaned paths back into the POV Connection column.

Does inverting a channel driver input change its simulated value?

Inverting the input pin inverts the signal entering the block. If simulation mode (SimOn = 1) is active, the simulated value bypasses the input pin and is not inverted by the pin dot.