SNPX overview

SNPX (also known as RobotIF, Robot Interface, or SRTP) is a high-performance binary protocol for reading and writing data on a Fanuc robot controller in less than 2 ms.

Key features

• Registers: Read/write numeric (R[]), position (PR[]), string (SR[]), and flag (F[]) registers
• I/O signals: Read/write 13 digital signal types and 5 numeric I/O types
• System variables: Read/write integer, real, position, and string variables
• Current position: Read world and user frame positions for any group
• Alarms: Read active alarm, alarm history, clear alarms
• Task monitoring: Read running program status, line number, and caller
• Batch reading: Read groups of data in a single command for maximum throughput
• Comments: Read/write descriptions for registers and I/O

Quick example

using UnderAutomation.Fanuc;
using UnderAutomation.Fanuc.Common;

  public class Snpx
  {
    static void Main()
    {
      // Create a new Fanuc robot instance
      FanucRobot robot = new FanucRobot();

      // Set connection parameters
      ConnectionParameters parameters = new ConnectionParameters("192.168.0.1");
      parameters.Snpx.Enable = true;

      // Connect to the robot
      robot.Connect(parameters);

      
      // Read a register
      Position posReg1 = robot.Snpx.PositionRegisters.Read(1);
      float numReg5 = robot.Snpx.NumericRegisters.Read(5);
      string strReg10 = robot.Snpx.StringRegisters.Read(10);

      // Write a register
      posReg1.CartesianPosition.X = 100;
      robot.Snpx.PositionRegisters.Write(1, posReg1);
      robot.Snpx.NumericRegisters.Write(2, 123.45f);
      robot.Snpx.StringRegisters.Write(3, "Hello, world!");

      // Read a variable
      int rmtMaster = robot.Snpx.IntegerSystemVariables.Read("$RMT_MASTER");
      string lastAlm = robot.Snpx.StringSystemVariables.Read("$ALM_IF.$LAST_ALM");
      Position cellFloor = robot.Snpx.PositionSystemVariables.Read("$CELL_FLOOR");

      // Write a system variable
      robot.Snpx.IntegerSystemVariables.Write("$RMT_MASTER", 1);
      robot.Snpx.StringSystemVariables.Write("$ALM_IF.$LAST_ALM", "No alarms");
      robot.Snpx.PositionSystemVariables.Write("$CELL_FLOOR", cellFloor);

      // Write a Karel program variable
      robot.Snpx.IntegerSystemVariables.Write("$[KarelProgram]KarelVariable", 1);

      // Read and Write I/O (SDI,SDO,RDI,RDO,UI,UO,SI,SO,WI,WO,WSI,PMC_K,PMC_R)
      robot.Snpx.RDO.Write(1, true);
      ushort ai5 = robot.Snpx.AI.Read(5);

      // Read and Write analogs (AI,AO,GI,GO,PMC_D)
      robot.Snpx.AO.Write(2, 5);
      ushort ao3 = robot.Snpx.AO.Read(3);

      // Clear alarms
      robot.Snpx.ClearAlarms();
      
    }

  }

Differences with official Fanuc Robot Interface

Fanuc provides its own Robot Interface client (FRRJIF.DLL). Here are the main differences:

Robot options

To enable SNPX on your robot, you need one of the following:

• FANUC America (R650 FRA): Option R553 "HMI Device SNPX" is required
• FANUC Ltd. (R651 FRL): No additional option needed

TCP port 60008 (Robot IF Server) must be accessible on your controller.

Performance

SNPX is the fastest protocol in the SDK. Regardless of the amount of data transported in a single command, execution time remains constant at approximately 2 ms.

For example, you can read 80 position registers in a single batch in the same time as reading a single variable.

When used with ROBOGUIDE, execution times under 1 ms can be achieved.

Connection

static void Main()
{
// Via FanucRobot
var robot = new FanucRobot();
var parameters = new ConnectionParameters("192.168.0.1");
parameters.Snpx.Enable = true;
robot.Connect(parameters);

// Or standalone
var snpx = new SnpxClient();
snpx.Connect("192.168.0.1");
}
}

Check if SNPX is available

parameters.Ftp.FtpPassword = "";
robot.Connect(parameters);
Features features = robot.Ftp.GetSummaryDiagnostic().Features;
bool isSnpxAvailable = features.HasSnpx;
}
}

Next steps

• Registers : R[], PR[], SR[], F[]
• Inputs & Outputs : Digital and numeric signals
• System variables : Integer, real, position, string variables
• Current position : World and user frame positions
• Alarms & task status : Alarm management and task monitoring
• Batch reading : High-performance batch operations

Demonstration

You can download the Windows Forms Desktop project which implements all SNPX features from the download page.

API reference