UDP

UDP Interface Overview

The UDP Interface provides high-performance signal communication with minimal cycle times, offering swift connectivity between applications and realvirtual.io. It supports automatic signal configuration through CSV symbol table import, making integration with PLCs and external systems quick and efficient.

Interface Properties

The UDP interface operates using separate sending and listening ports. It’s crucial to assign distinct ports for sending and listening purposes. All PLCInput signals are transmitted to the remote partner, while all PLCOutput signals are received from the remote partner.

Basic Properties

Remote Listen Port - UDP port number on the remote machine where messages are sent (default: 11000)
Local Listen Port - UDP port number on the local machine for receiving incoming messages (default: 11001)
Remote IP Address - IP address of the remote machine to send UDP messages to (e.g., 127.0.0.1 for localhost)
Debug Mode - Enables detailed logging of sent and received UDP messages for troubleshooting

CSV Symbol Table Properties

Symbol Table - Path to the CSV symbol table file containing signal definitions
Split Char - Character delimiter used to separate columns in the CSV file (typically semicolon or comma)

When using the UDP Interface, all signals are transmitted and received in the form of a byte array, ensuring the most efficient packet size. Each signal must define a value in its Name property to indicate its position in the byte array. Since there is a single sending and receiving message, the positions of inputs and outputs may overlap. Signal data sizes must adhere to the following guidelines:

Boolean: Always occupies the first bit in one full byte (1 byte total)
Integer: Occupies 4 bytes
Float (REAL): Occupies 4 bytes

CSV Symbol Table Import

The UDP Interface supports automatic signal configuration through CSV symbol table import. This feature allows you to quickly configure all signals by importing a CSV file exported from your PLC or SCADA system.

CSV File Format

The CSV file must contain three columns with a header row:

Name;Type;Direction
SpeedSetpoint;REAL;PLC_IN
CurrentSpeed;REAL;PLC_OUT
StartButton;BOOL;PLC_IN
RunningStatus;BOOL;PLC_OUT
ErrorCode;INT;PLC_OUT
TargetPosition;INT;PLC_IN

Column Definitions:

Name - The signal name (will be used as SymbolName in realvirtual)
Type - Data type of the signal
- BOOL - Boolean value (1 byte)
- INT - Integer value (4 bytes)
- REAL - Float value (4 bytes)
- TEXT, STRING, WSTRING - Text values (limited support)
Direction - Signal direction
- PLC_IN - INPUT signal (Unity → External application)
- PLC_OUT - OUTPUT signal (External application → Unity)

Using CSV Import

Export Symbol Table from your PLC/SCADA system in CSV format
Select Symbol Table - Click the “Select symbol table” button in the Inspector to choose your CSV file
Import - Click the “Import symbol table” button to automatically create all signals

The import process will:

Automatically create signals for each row in the CSV
Calculate byte positions sequentially for INPUT and OUTPUT signals separately
Display the total number of signals imported and byte sizes for each direction

Example Console Output:

Successfully imported 6 signals from C:\symbols.csv
Total byte sizes - Inputs (Unity→PLC): 12 bytes, Outputs (PLC→Unity): 13 bytes

Signal Byte Positioning

The import automatically calculates byte positions:

INPUT signals (PLC_IN) - Byte positions start at 0 and increment based on data type size
OUTPUT signals (PLC_OUT) - Byte positions start at 0 and increment independently from inputs

Example:

Signal Name	Type	Direction	Byte Position	Size
StartButton	BOOL	PLC_IN	0	1 byte
TargetPosition	INT	PLC_IN	1	4 bytes
SpeedSetpoint	REAL	PLC_IN	5	4 bytes
RunningStatus	BOOL	PLC_OUT	0	1 byte
CurrentSpeed	REAL	PLC_OUT	1	4 bytes
ErrorCode	INT	PLC_OUT	5	4 bytes

Total Message Sizes:

INPUT message (Unity → PLC): 9 bytes
OUTPUT message (PLC → Unity): 9 bytes

Common Use Cases

PLC Integration - Exchange data with Siemens, Beckhoff, or other PLC systems via UDP
SCADA Communication - Connect to SCADA systems for real-time data exchange
SEW Drive Integration - Import signal tables from SEW Eurodrive systems
Custom Tools - Communicate with custom Python, C#, or other applications
High-Speed Data Exchange - Minimal overhead for fast cycle times