toggleSwitch

Parameter	Description
output ports	1 output port(s) declared.

📄Description

Outputs one of two configured values from state.

Module	`nflow_blocks`
Library	Utility blocks
Type	`toggleSwitch`
Label	Toggle Switch

Description

Two-state toggle source. The block has no inputs and a single output that

Ports

Input(s)

This block declares no input ports.

Output(s)

Port	Role	Side	Position
Port_1	Numeric signal produced by the block.	right	x=80, y=25

Parameters

Parameter	Default value
`state`	0
`onLabel`	ON
`offLabel`	OFF
`onValue`	1
`offValue`	0

Inspector Keys

These serialized keys are exposed by the block inspector.

state
onLabel
offLabel
onValue
offValue

Block Characteristics

Block type	toggleSwitch
Family	Utility blocks
Rendered size	80 x 50
Phases	OUTPUT
Direct feedthrough	see Algorithms
Internal state or history	yes
Signal data type	double numeric values

Algorithms

OUTPUT block with no inputs.
Nonzero state outputs onValue; zero state outputs offValue.
onLabel and offLabel affect UI labels only.

Equation or Rule

$$y = \begin{cases} onValue, & state \ne 0 \\ offValue, & state = 0 \end{cases}$$

Extended Capabilities

This page describes the native runtime behavior observed in the module C++ sources. Declared phases indicate when the simulation engine calls the block.

Code generation: supported for C and Rust.

Implementation Sources

Manifestmodules/nflow_blocks/libraries/utility/library.json

{
  "id": "builtin.utility",
  "title": "Utility",
  "version": "1.0.0",
  "format": "nflow-2",
  "metadata": {
    "author": "Allan CORNET",
    "created": "2026-03-21",
    "tool": "Nelson nflow"
  },
  "comment": "Utility blocks such as switches, comments, and subsystems",
  "license": "LGPL-3.0",
  "builtin": true,
  "blocks": [
    {
      "type": "comment",
      "label": "Comment",
      "icon": "comment.svg",
      "phases": [],
      "width": 220,
      "height": 120,
      "inputs": [],
      "outputs": [],
      "defaultParams": {
        "CommentText": "",
        "ShowBorder": true
      },
      "render": {
        "type": "comment",
        "bodyClass": "block-body"
      }
    },
    {
      "type": "switch",
      "label": "Switch",
      "icon": "switch.svg",
      "phases": [
        "ALGEBRAIC"
      ],
      "width": 80,
      "height": 80,
      "inputs": [
        {
          "x": 0,
          "y": 0,
          "side": "left"
        },
        {
          "x": 0,
          "y": 40,
          "side": "left"
        },
        {
          "x": 0,
          "y": 80,
          "side": "left"
        }
      ],
      "outputs": [
        {
          "x": 80,
          "y": 40,
          "side": "right"
        }
      ],
      "defaultParams": {
        "Criteria": "ge",
        "Threshold": 0
      },
      "render": {
        "type": "math",
        "bodyClass": "block-body",
        "mathGroupClass": "switch-math"
      }
    },
    {
      "type": "multiportSwitch",
      "label": "Multiport Switch",
      "icon": "multiportSwitch.svg",
      "phases": [
        "ALGEBRAIC"
      ],
      "width": 40,
      "height": 80,
      "inputs": [
        {
          "x": 20,
          "y": 0,
          "side": "top"
        },
        {
          "x": 0,
          "y": 20,
          "side": "left"
        },
        {
          "x": 0,
          "y": 40,
          "side": "left"
        },
        {
          "x": 0,
          "y": 60,
          "side": "left"
        }
      ],
      "outputs": [
        {
          "x": 40,
          "y": 40,
          "side": "right"
        }
      ],
      "defaultParams": {
        "DataPortCount": 3
      },
      "render": {
        "type": "image",
        "src": "exports/multiportSwitch.svg",
        "svgMode": "element",
        "preserveAspectRatio": "none",
        "x": 0,
        "y": 0,
        "width": 40,
        "height": 90
      }
    },
    {
      "type": "toggleSwitch",
      "label": "Toggle Switch",
      "icon": "toggleSwitch.svg",
      "phases": [
        "OUTPUT"
      ],
      "width": 80,
      "height": 50,
      "inputs": [],
      "outputs": [
        {
          "x": 80,
          "y": 25,
          "side": "right"
        }
      ],
      "defaultParams": {
        "State": 0,
        "OnLabel": "ON",
        "OffLabel": "OFF",
        "OnValue": 1,
        "OffValue": 0
      },
      "render": {
        "type": "toggle"
      }
    },
    {
      "type": "subsystem",
      "icon": "subsystem.svg",
      "label": "Subsystem",
      "phases": [
        "INIT",
        "OUTPUT",
        "ALGEBRAIC",
        "UPDATE"
      ],
      "width": 120,
      "height": 80,
      "inputs": [
        {
          "x": 0,
          "y": 40,
          "side": "left"
        }
      ],
      "outputs": [
        {
          "x": 120,
          "y": 40,
          "side": "right"
        }
      ],
      "defaultParams": {
        "name": "Subsystem",
        "externalInputs": [],
        "externalOutputs": [],
        "subsystem": null
      },
      "render": {
        "type": "math",
        "bodyClass": "block-body",
        "mathGroupClass": "subsystem-math",
        "formula": "\\mathsf{Sub}"
      }
    },
    {
      "type": "mux",
      "label": "Mux",
      "icon": "mux.svg",
      "phases": [
        "OUTPUT"
      ],
      "width": 8,
      "height": 40,
      "inputs": [
        {
          "x": 0,
          "y": 10,
          "side": "left"
        },
        {
          "x": 0,
          "y": 30,
          "side": "left"
        }
      ],
      "outputs": [
        {
          "x": 8,
          "y": 20,
          "side": "right"
        }
      ],
      "defaultParams": {
        "Inputs": 2
      }
    },
    {
      "type": "demux",
      "label": "Demux",
      "icon": "demux.svg",
      "phases": [
        "OUTPUT"
      ],
      "width": 8,
      "height": 40,
      "inputs": [
        {
          "x": 0,
          "y": 20,
          "side": "left"
        }
      ],
      "outputs": [
        {
          "x": 8,
          "y": 10,
          "side": "right"
        },
        {
          "x": 8,
          "y": 30,
          "side": "right"
        }
      ],
      "defaultParams": {
        "Outputs": 2
      }
    },
    {
      "type": "convert",
      "label": "Convert",
      "icon": "convert.svg",
      "phases": [
        "ALGEBRAIC"
      ],
      "width": 90,
      "height": 50,
      "inputs": [
        {
          "x": 0,
          "y": 25,
          "side": "left"
        }
      ],
      "outputs": [
        {
          "x": 90,
          "y": 25,
          "side": "right"
        }
      ],
      "defaultParams": {
        "OutDataType": "double",
        "SaturateOnOverflow": true,
        "Rounding": "nearest"
      }
    },
    {
      "type": "initialCondition",
      "label": "IC",
      "icon": "initialCondition.svg",
      "phases": [
        "ALGEBRAIC"
      ],
      "width": 90,
      "height": 50,
      "inputs": [
        {
          "x": 0,
          "y": 25,
          "side": "left"
        }
      ],
      "outputs": [
        {
          "x": 90,
          "y": 25,
          "side": "right"
        }
      ],
      "defaultParams": {
        "InitialValue": 0
      }
    },
    {
      "type": "dataStoreMemory",
      "label": "Data Store Memory",
      "icon": "dataStoreMemory.svg",
      "phases": [
        "INIT"
      ],
      "width": 70,
      "height": 60,
      "inputs": [],
      "outputs": [],
      "defaultParams": {
        "DataStoreName": "A",
        "InitialValue": 0
      },
      "render": {
        "type": "image",
        "src": "exports/dataStoreMemory.svg",
        "svgMode": "element",
        "preserveAspectRatio": "none",
        "x": 0,
        "y": 0,
        "width": 70,
        "height": 60
      }
    },
    {
      "type": "dataStoreWrite",
      "label": "Data Store Write",
      "icon": "dataStoreWrite.svg",
      "phases": [
        "INIT",
        "UPDATE"
      ],
      "width": 70,
      "height": 60,
      "inputs": [
        {
          "x": 0,
          "y": 30,
          "side": "left"
        }
      ],
      "outputs": [],
      "defaultParams": {
        "DataStoreName": "A"
      },
      "render": {
        "type": "image",
        "src": "exports/dataStoreWrite.svg",
        "svgMode": "element",
        "preserveAspectRatio": "none",
        "x": 0,
        "y": 0,
        "width": 70,
        "height": 60
      }
    },
    {
      "type": "dataStoreRead",
      "label": "Data Store Read",
      "icon": "dataStoreRead.svg",
      "phases": [
        "OUTPUT"
      ],
      "width": 70,
      "height": 60,
      "inputs": [],
      "outputs": [
        {
          "x": 70,
          "y": 30,
          "side": "right"
        }
      ],
      "defaultParams": {
        "DataStoreName": "A"
      },
      "render": {
        "type": "image",
        "src": "exports/dataStoreRead.svg",
        "svgMode": "element",
        "preserveAspectRatio": "none",
        "x": 0,
        "y": 0,
        "width": 70,
        "height": 60
      }
    },
    {
      "type": "selector",
      "label": "Selector",
      "icon": "selector.svg",
      "phases": [
        "ALGEBRAIC"
      ],
      "width": 80,
      "height": 50,
      "inputs": [
        {
          "x": 0,
          "y": 25,
          "side": "left"
        }
      ],
      "outputs": [
        {
          "x": 80,
          "y": 25,
          "side": "right"
        }
      ],
      "defaultParams": {
        "Indices": "1"
      }
    },
    {
      "type": "reshape",
      "label": "Reshape",
      "icon": "reshape.svg",
      "phases": [
        "INIT",
        "ALGEBRAIC"
      ],
      "width": 80,
      "height": 50,
      "inputs": [
        {
          "x": 0,
          "y": 25,
          "side": "left"
        }
      ],
      "outputs": [
        {
          "x": 80,
          "y": 25,
          "side": "right"
        }
      ],
      "defaultParams": {
        "OutputDimensions": ""
      }
    },
    {
      "type": "concatenate",
      "label": "Concatenate",
      "icon": "concatenate.svg",
      "phases": [
        "ALGEBRAIC"
      ],
      "width": 60,
      "height": 60,
      "inputs": [
        {
          "x": 0,
          "y": 20,
          "side": "left"
        },
        {
          "x": 0,
          "y": 40,
          "side": "left"
        }
      ],
      "outputs": [
        {
          "x": 60,
          "y": 30,
          "side": "right"
        }
      ],
      "defaultParams": {
        "ConcatenateDimension": 1
      }
    },
    {
      "type": "busCreator",
      "label": "Bus Creator",
      "icon": "busCreator.svg",
      "phases": [
        "ALGEBRAIC"
      ],
      "width": 80,
      "height": 70,
      "inputs": [
        {
          "x": 0,
          "y": 25,
          "side": "left"
        },
        {
          "x": 0,
          "y": 45,
          "side": "left"
        }
      ],
      "outputs": [
        {
          "x": 80,
          "y": 35,
          "side": "right"
        }
      ],
      "defaultParams": {
        "BusType": "",
        "NonVirtual": false,
        "MemberNames": []
      }
    },
    {
      "type": "busSelector",
      "label": "Bus Selector",
      "icon": "busSelector.svg",
      "phases": [
        "ALGEBRAIC"
      ],
      "width": 85,
      "height": 70,
      "inputs": [
        {
          "x": 0,
          "y": 35,
          "side": "left"
        }
      ],
      "outputs": [
        {
          "x": 85,
          "y": 25,
          "side": "right"
        },
        {
          "x": 85,
          "y": 45,
          "side": "right"
        }
      ],
      "defaultParams": {
        "SelectedSignals": [],
        "OutputAsBus": false
      }
    },
    {
      "type": "merge",
      "label": "Merge",
      "icon": "merge.svg",
      "phases": [
        "INIT",
        "ALGEBRAIC"
      ],
      "width": 40,
      "height": 80,
      "inputs": [
        {
          "x": 0,
          "y": 30,
          "side": "left"
        },
        {
          "x": 0,
          "y": 50,
          "side": "left"
        }
      ],
      "outputs": [
        {
          "x": 40,
          "y": 40,
          "side": "right"
        }
      ],
      "defaultParams": {
        "InitialOutput": 0
      },
      "render": {
        "type": "image",
        "src": "exports/merge.svg",
        "svgMode": "element",
        "preserveAspectRatio": "none",
        "x": 0,
        "y": 0,
        "width": 40,
        "height": 80
      }
    },
    {
      "type": "functionCallGenerator",
      "label": "Function-Call Generator",
      "icon": "functionCallGenerator.svg",
      "phases": [
        "ALGEBRAIC"
      ],
      "width": 90,
      "height": 60,
      "inputs": [],
      "outputs": [
        {
          "x": 90,
          "y": 30,
          "side": "right"
        }
      ],
      "defaultParams": {
        "NumberOfIterations": 1
      },
      "render": {
        "type": "image",
        "src": "exports/functionCallGenerator.svg",
        "svgMode": "element",
        "preserveAspectRatio": "none",
        "x": 0,
        "y": 0,
        "width": 90,
        "height": 60
      }
    },
    {
      "type": "functionCallSplit",
      "label": "Function-Call Split",
      "icon": "functionCallSplit.svg",
      "phases": [],
      "width": 60,
      "height": 80,
      "inputs": [
        {
          "x": 0,
          "y": 40,
          "side": "left"
        }
      ],
      "outputs": [
        {
          "x": 60,
          "y": 30,
          "side": "right"
        },
        {
          "x": 60,
          "y": 50,
          "side": "right"
        }
      ],
      "defaultParams": {},
      "render": {
        "type": "image",
        "src": "exports/functionCallSplit.svg",
        "svgMode": "element",
        "preserveAspectRatio": "none",
        "x": 0,
        "y": 0,
        "width": 60,
        "height": 80
      }
    },
    {
      "type": "iteratorNumber",
      "label": "Iterator Number",
      "icon": "iteratorNumber.svg",
      "phases": [
        "OUTPUT"
      ],
      "width": 70,
      "height": 50,
      "inputs": [],
      "outputs": [
        {
          "x": 70,
          "y": 25,
          "side": "right"
        }
      ],
      "defaultParams": {},
      "render": {
        "type": "image",
        "src": "exports/iteratorNumber.svg",
        "svgMode": "element",
        "preserveAspectRatio": "none",
        "x": 0,
        "y": 0,
        "width": 70,
        "height": 50
      }
    },
    {
      "type": "iteratorCondition",
      "label": "Iterator Condition",
      "icon": "iteratorCondition.svg",
      "phases": [
        "ALGEBRAIC"
      ],
      "width": 70,
      "height": 50,
      "inputs": [
        {
          "x": 0,
          "y": 25,
          "side": "left"
        }
      ],
      "outputs": [
        {
          "x": 70,
          "y": 25,
          "side": "right"
        }
      ],
      "defaultParams": {},
      "render": {
        "type": "image",
        "src": "exports/iteratorCondition.svg",
        "svgMode": "element",
        "preserveAspectRatio": "none",
        "x": 0,
        "y": 0,
        "width": 70,
        "height": 50
      }
    },
    {
      "type": "width",
      "label": "Width",
      "icon": "width.svg",
      "phases": [
        "ALGEBRAIC"
      ],
      "width": 80,
      "height": 50,
      "inputs": [
        {
          "x": 0,
          "y": 25,
          "side": "left"
        }
      ],
      "outputs": [
        {
          "x": 80,
          "y": 25,
          "side": "right"
        }
      ],
      "defaultParams": {}
    },
    {
      "type": "signalConversion",
      "label": "Signal Conversion",
      "icon": "signalConversion.svg",
      "phases": [
        "ALGEBRAIC"
      ],
      "width": 90,
      "height": 50,
      "inputs": [
        {
          "x": 0,
          "y": 25,
          "side": "left"
        }
      ],
      "outputs": [
        {
          "x": 90,
          "y": 25,
          "side": "right"
        }
      ],
      "defaultParams": {}
    },
    {
      "type": "assignment",
      "label": "Assignment",
      "icon": "assignment.svg",
      "phases": [
        "ALGEBRAIC"
      ],
      "width": 90,
      "height": 60,
      "inputs": [
        {
          "x": 0,
          "y": 20,
          "side": "left"
        },
        {
          "x": 0,
          "y": 40,
          "side": "left"
        }
      ],
      "outputs": [
        {
          "x": 90,
          "y": 30,
          "side": "right"
        }
      ],
      "defaultParams": {
        "Indices": [
          1
        ]
      }
    },
    {
      "type": "busAssignment",
      "label": "Bus Assignment",
      "icon": "busAssignment.svg",
      "phases": [
        "ALGEBRAIC"
      ],
      "width": 100,
      "height": 60,
      "inputs": [
        {
          "x": 0,
          "y": 20,
          "side": "left"
        },
        {
          "x": 0,
          "y": 40,
          "side": "left"
        }
      ],
      "outputs": [
        {
          "x": 100,
          "y": 30,
          "side": "right"
        }
      ],
      "defaultParams": {
        "AssignedSignals": []
      }
    }
  ]
}

Runtimemodules/nflow_blocks/src/cpp/source/toggleSwitch.cpp

//=============================================================================
// Copyright (c) 2016-present Allan CORNET (Nelson)
//=============================================================================
// This file is part of Nelson.
//=============================================================================
// LICENCE_BLOCK_BEGIN
// SPDX-License-Identifier: LGPL-3.0-or-later
// LICENCE_BLOCK_END
//=============================================================================
#include "SimEngineTypes.hpp"
#include "BlockRegistry.hpp"
#include "FieldNames.hpp"
#include "NFlowBlockDescriptor.hpp"
#include <cmath>
#include <algorithm>
#include "source_blocks.hpp"
//=============================================================================
bool
Nelson::NFlow::handleToggleSwitch(SimCtx& ctx, const Block& b, Phase phase)
{
    if (phase != Phase::OUTPUT) {
        return false;
    }
    nflow::BlockDescriptor bd(b, ctx.variables);
    double state = bd.paramDouble(nflow::kState, 0.0);
    double onVal = bd.paramDouble(nflow::kOnValue, 1.0);
    double offVal = bd.paramDouble(nflow::kOffValue, 0.0);
    setOutput(ctx, b.nid, (state != 0.0) ? onVal : offVal);
    return false;
}
//=============================================================================
Nelson::NFlow::BlockCodegenTemplate
Nelson::NFlow::getCodeGenCToggleSwitch()
{
    BlockCodegenTemplate t;
    t.step = "out_{id} = ({param:State:0.0} ? {param:OnValue:1.0} : {param:OffValue:0.0});";
    return t;
}
//=============================================================================
Nelson::NFlow::BlockCodegenTemplate
Nelson::NFlow::getCodeGenRustToggleSwitch()
{
    BlockCodegenTemplate t;
    t.step = "out_{id} = if {param:State:0.0} != 0.0_f64 { {param:OnValue:1.0} } else { "
             "{param:OffValue:0.0} };";
    return t;
}
//=============================================================================