@vitormnm/node-red-instructions-ladder-iec-61131-3 1.0.4
Node-RED instructions ladder IEC-61131-3
A Node-RED node that provides common IEC 61131-3 Ladder Logic instructions for building PLC-style logic flows directly inside Node-RED.
Features
Contacts
| Instruction | Description |
|---|---|
| NO | Normally Open contact. Passes execution when the source value is true. |
| NC | Normally Closed contact. Passes execution when the source value is false. |
Comparison Instructions
| Instruction | Description |
|---|---|
| EQ | Equal (==) |
| NEQ | Not Equal (!=) |
| GT | Greater Than (>) |
| GE | Greater Than or Equal (>=) |
| LT | Less Than (<) |
| LE | Less Than or Equal (<=) |
Math Instructions
| Instruction | Description |
|---|---|
| ADD | Addition |
| SUB | Subtraction |
| MUL | Multiplication |
| DIV | Division |
| MOD | Modulus |
| ABS | Absolute value |
| SQR | Square root |
| MOV | Move value |
Output Instructions
| Instruction | Description |
|---|---|
| SET | Sets the destination variable to true |
| RESET | Sets the destination variable to false |
Supported Data Sources
Input values can be read from:
msgflowglobal- Numeric constants
- Boolean constants
- String constants
Output values can be written to:
msgflowglobal
Status Display
The node provides a compact real-time status display similar to PLC ladder diagnostics.
Examples:
NO motor_run(true)→TRUE
GT temp(85)>limit(80)→TRUE
ADD a(10)+b(5)→result=15
DIV x(9)/y(0)→÷0ERR
SET →motor=TRUE
RST →alarm=FALSE
The status indicator also changes color:
- Green = instruction result is TRUE
- Gray = instruction result is FALSE
- Red = execution error
Example
Greater Than Comparison
Source A: msg.temperature
Source B: msg.limit
Instruction: GT
Input:
{
"temperature": 85,
"limit": 80
}
Result:
{
"ladder": {
"func": "GT",
"result": true
}
}
Addition
Source A: msg.value1
Source B: msg.value2
Instruction: ADD
Destination: msg.result
Input:
{
"value1": 10,
"value2": 5
}
Output:
{
"value1": 10,
"value2": 5,
"result": 15
}
IEC 61131-3 Inspired
This node is inspired by the instruction set commonly found in PLC programming environments implementing the IEC 61131-3 standard.
It allows Node-RED users to create ladder-style logic using familiar industrial automation instructions without requiring a PLC.
Installation
npm install @vitormnm/node-red-instructions-ladder-iec-61131-3
Restart Node-RED after installation.
License
MIT
