This repository contains a complete TwinCAT 3 PLC example implementation demonstrating TCP/IP communication with the Navitec Navitrol navigation system using the Ethernet Supervisor Interface Protocol Version 4.

• Overview
• Test Environment Specifications
• Implemented Messages
• Protocol Implementation
  • Message Flow
  • How Received Messages Are Handled
• Customization Guide
  • Adding New Message Types
  • Adjusting Cycle Times
• Additional Resources
• Support

Hardware:

• Test fixture: Beckhoff C6032-0080
  • Note: Please work with your local Beckhoff team to understand what IPC makes sense for your application

Beckhoff RT Linux®:

• Version: 13
• Build: 262191
• Update: 19.12.2025

Beckhoff RT Linux® Packages:

• tf6310-tcp-ip version 2.0.22-1
• tc31-xar-um version 4026.21.107-1

Navitec Software:

• Navitrol 7.1.0-alpha.1.deb
• NavitrolMonitor_1.70.00_Navitrol_7.1.0-alpha.1.zip
• Ethernet Supervisor Documentation dated 17.10.2025

Development PC:

• TwinCAT XAE 3.1.4026.20
• TF6310 3.3.23

Important parameters for Ethernet Supervisor interface:

I,supervisor_eth_port,                  2000       # Supervisor communication port (1-65535)
I,supervisor_eth_server,                0          # Server mode: 0=client, 1=server
I,supervisor_eth_endianness,            0          # Endianness: 0=little endian, 1=big endian
I,supervisor_eth_enabled,               1          # Enable Supervisor interface
I,control_interval_us,                  30000      # min 100, max 100000

Note: A copy of the complete parameter file used for testing is stored in this repository at Navitrol Param File/params.txt.

Sequence:

1. Supervisor sends 3002 (Supervisor Status) → Navitrol responds with 3102 (Navitrol Status)
2. Supervisor sends 1026 (Measurement Update) → Navitrol responds with 1126 (Motor Control)
3. When needed, Supervisor sends 1001 (Initialize Position) → Navitrol responds with 1100, then 1101

Cyclic Operation:

• 3002 sent every 100ms (configurable via FB_Supervisor.CycleTime3002)
  • Maximum interval: 1 second
• 1026 sent every 30ms (configurable via FB_Supervisor.CycleTime1026)
  • Must match Navitrol parameter control_interval_us in params.txt
  • Refer to "Measurement update message" in the glossary section of Navitrol documentation Section 11.1
• Responses received asynchronously via continuous socket receive

Incoming messages are received into a union buffer that acts as a raw byte array:

// Bytes bucket to buffer received messages.
// Header info is parsed before being copied into the correct message structure.
// PLC logic is built expecting to receive the entire TCP message payload with one call to FB_SocketReceive.
// FB_SocketReceive will fragment the received data if the receive buffer is not large enough.
// Make sure this is large enough to fit the biggest received message.
TYPE U_Received_bytes_from_Navitrol : UNION
    Header : ST_SupervisorHeader;
    Bytes  : ARRAY[0..Param_Supervisor_response.ReceivedBytesBufferSize] OF UINT;
END_UNION
END_TYPE

How it works:

1. Raw TCP data is received into the Bytes array
2. The Header overlay allows reading the message type without copying
3. Message is identified by Header.Message_ID
4. Full message is copied to the appropriate typed output variable using MEMCPY

This pattern ensures the receive buffer is large enough for any message type while maintaining type safety for processed messages.

Follow the established pattern to add new messages:

1. Create the struct in the appropriate folder:

   • Outgoing: Supervisor to Navitrol message/<MessageID>/
   • Incoming: Navitrol to Supervisor response/<MessageID>/

2. Define the struct:

   {attribute 'pack_mode' := '1'}  // Byte-aligned
   TYPE ST_<MessageID>_<Description> EXTENDS ST_SupervisorHeader : STRUCT
       // Then: Payload fields
       Field1 : UINT;
       Field2 : REAL;
       // ...
   END_STRUCT
   END_TYPE
   

3. For outgoing messages:

   • Call F_SetHeaderInfo(message) and F_SetSectionHeaderInfo() (in the case of msg 3002) before sending
   • Add send logic in FB_Supervisor COMS_ACTIVE state (or create new internal METHOD following the pattern of SendMsg3002(), SendMsg1026(), SendMsg1001())
   • Create timer if cyclic, or event trigger if on-demand

4. For incoming messages:

   • Add CASE handler in ReceiveAllMsgsAndParse() METHOD in FB_Supervisor
   • Add output variable to FB_Supervisor for storing the received message
   • Use MEMCPY to copy from ReceiveBuffer union to the typed output variable

   Example pattern:

   // In ReceiveAllMsgsAndParse() method:
   CASE ReceiveBuffer.Header.Message_ID OF
       // ... existing cases ...
       2050:
           NumOf2050MsgReceived := NumOf2050MsgReceived + 1;
           MEMCPY(destAddr := ADR(st2050_New_Message),
                  srcAddr := ADR(ReceiveBuffer),
                  n := SIZEOF(st2050_New_Message));
   

Modify cycle times based on your system requirements:

Supervisor : FB_Supervisor := (
    CycleTime3002 := T#100MS,  // Supervisor status (default: 100ms)
    CycleTime1026 := T#30MS    // Measurement update (default: 30ms)
);

Important: Measurement update interval must match Navitrol's control_interval_us parameter (default: 30ms ±20% tolerance). Please refer to Navitrol documentation Section 11.1 "Ethernet Supervisor" - Glossary - Measurement update message.

Refer to your Navitrol documentation package for:

• Complete message specifications (Section 11.1)
• Parameter reference (supervisor_eth_* parameters)
• Error code descriptions
• Timing requirements and best practices

• TF6310 TCP/IP function documentation
• Beckhoff RT Linux®

• The Navitrol Ethernet Supervisor Interface protocol is proprietary to Navitec Systems Oy
• Contact Navitec Systems for licensing and commercial use of Navitrol

All sample code provided by Beckhoff Automation LLC are for illustrative purposes only and are provided "as is" and without any warranties, express or implied. Actual implementations in applications will vary significantly. Beckhoff Automation LLC shall have no liability for, and does not waive any rights in relation to, any code samples that it provides or the use of such code samples for any purpose.

For issues related to:

• This example code: Open an issue in this repository
• Navitrol software: Contact Navitec Systems support
• TwinCAT/Beckhoff: Contact Beckhoff Automation support