Implementing Central Cross-Diagram Operator Controls and Variables in SIMIT Simulation Platform

To control multiple simulation components distributed across separate diagram charts from a single central operator diagram (e.g., a central 'Safety Reset' pushbutton resetting multiple safety module diagrams) in SIMIT, you do not need physical wiring lines. SIMIT operates on a global signal architecture. To implement this: (1) Place the Pushbutton or Switch component on the central operator diagram, creating an internal output signal (e.g., 'Bedien_Diagram/Btn_Reset'); (2) On each target safety module diagram, place a 'Connector' component (from SIMIT Library -> Standard components -> Connectors), enter the name of the central pushbutton signal in its properties, and wire the connector output into the safety module input; or (3) Declare a global 'User Signal' in the Task Navigator and bind both the switch and safety modules to that shared variable.

Executive Summary

In virtual commissioning environments modeled with the SIMIT Simulation Platform (V9, V10, V11), complex plant models are typically partitioned into modular diagram charts—such as separate diagrams for individual conveyor skids, emergency shutdown (ESD) safety modules, and pneumatic actuator loops. Simulation engineers frequently need to consolidate manual operator actions—such as a global plant emergency stop, area master reset, or test scenario trigger—onto a dedicated 'Control / Bedien' diagram without duplicating pushbuttons on every sub-diagram. Inquiries regarding how to instantiate global variables in SIMIT and link a single switch to multiple remote charts highlight SIMIT's wireless signal propagation architecture and the proper usage of Connector components and User Signals.

Architecture and Fundamental Mechanics

The signal propagation and variable architecture of SIMIT operate through global namespace routing:

SIMIT's Wireless Signal Paradigm: Unlike physical CAD schematics or CFC charts where connections require visible lines, SIMIT treats every output pin on every component as a globally unique, accessible signal. The full signal identifier follows the hierarchical path: <Diagram_Name>/<Component_Name>/<Output_Pin>. Any component anywhere in the SIMIT project can reference this signal without routing wires across diagrams.
Connector Components (Verbindungskomponenten):
- SIMIT provides specialized input and output Connectors located in the component library under Standard components -> Connectors.
- When an input Connector is placed on a chart, its property field accepts any valid signal name in the project.
- The connector acts as a wireless receiver, tapping into the source signal and delivering its real-time value to downstream logic blocks.
Internal Variables vs. User Signals (Globale Variablen):
- Component Internal Signals: Every switch, pushbutton, slider, or math block automatically generates internal signals representing its current state. A Pushbutton on diagram HMI_Overview named Btn_Reset inherently creates boolean signal HMI_Overview/Btn_Reset.
- User Signals: Located in the SIMIT Task Navigator under Signals -> User Signals. These are user-defined global memory tags independent of any specific component or diagram. A User Signal (e.g., Global_Safety_Reset of type Binary) can be driven by a switch and consumed by multiple chart connectors, couplings, or automated test scripts.
Decoupling Simulation Controls from AS Couplings: By driving internal SIMIT variables rather than direct PLC I/O signals, engineers can simulate local hardware buttons, field interlocks, and test stimuli completely within SIMIT without modifying the underlying S7-400 or S7-1500 PLC software.

Step-by-Step Implementation Procedure

Implement a central operator control driving distributed safety diagrams using the following procedure:

Method 1: Using SIMIT Connector Components (Fastest Implementation)

Create the Central Operator Diagram:
- In the SIMIT Task Navigator, right-click Diagrams and select New Diagram.
- Name the diagram HMI_Central_Controls.
- From the Component Library, expand Controls -> Pushbuttons.
- Drag a Pushbutton (or Switch) onto the diagram canvas.
- In its properties, set Name = Master_Safety_Reset and configure it as a momentary pushbutton (High when pressed).
- The system automatically creates signal: HMI_Central_Controls/Master_Safety_Reset.
Connect Remote Safety Diagrams via Connectors:
- Open the first target safety module diagram (e.g., Safety_Zone_1).
- From the Component Library, expand Standard components -> Connectors.
- Drag an Input Connector onto the diagram.
- In the connector properties, click the signal browse button (...) and select HMI_Central_Controls/Master_Safety_Reset.
- Wire the output pin of the connector directly into the Reset input pin of the Safety Zone 1 component.
- Repeat this step for Safety_Zone_2, Safety_Zone_3, and all other target diagrams.

Method 2: Using Global User Signals

In the Task Navigator, open Signals -> User Signals.
Click New Signal -> Name it Global_Safety_Reset -> set Data Type to Binary.
On your operator diagram, place a Pushbutton and wire its output to an Output Connector bound to Global_Safety_Reset.
On all safety module diagrams, place Input Connectors bound to Global_Safety_Reset.

Verification

Verify cross-diagram signal propagation in SIMIT runtime:

Start Simulation: Click the Start button on the SIMIT toolbar to activate the simulation engine.
Split Screen Monitoring: Open HMI_Central_Controls on one monitor and Safety_Zone_1 on a second monitor.
Button Actuation Test: Press the Master_Safety_Reset pushbutton on the central diagram. Confirm that the connector pins on all remote safety diagrams transition from 0 to 1 synchronously, resetting safety trip flags across all zones.
Signal List Audit: In the SIMIT Task Navigator, open Signals -> All Signals. Confirm that all connector inputs reflect identical boolean states matching the master switch.

Limitations and Operational Precautions

Avoid creating circular signal feedback loops between connectors without inserting time-delay or unit-delay components (e.g., Delay), as algebraic signal loops can cause simulation calculation stalls. Furthermore, ensure signal names are unique and descriptive; renaming a diagram or component will require updating any manually typed connector string references.

Engineer FAQ

Can a single SIMIT switch drive multiple components simultaneously?

Yes. Because SIMIT uses a global signal architecture, any number of Connector components across dozens of diagrams can read from a single switch output signal.

Where are Connector components located in the SIMIT library?

Connectors are located under Component Library -> Standard components -> Connectors.

What is the difference between a Connector and a User Signal in SIMIT?

A Connector connects directly to a component's output signal. A User Signal is an independent global tag created in the Task Navigator that can be manipulated by scripts, couplings, or components.