Master-Based Homing (DS402)

Table of Contents

• 🔹 What is Master-Based Homing?
• 🔹 How to Master-Based Home?
  • RMP Homing Parameters
• 🔹 Homing Methods
  • Improved DS402 Implementations (100-137)
  • Old DS402 Implementations (0-37)
• 📜 Sample Code

Utilize RapidSetup for master-based DS402 homing, which although subject to EtherCAT network latency, provides comprehensive control over homing methods, safety settings, and parameters for precise motion initialization.

🔹 What is Master-Based Homing?

Homing is the process of establishing a consistent starting point, enabling precise motion control to specific positions within your workspace.

Master-Based Homing refers to a homing sequence managed by the master controller (e.g., an industrial PC or PLC with EtherCAT master capabilities). In this case, the homing process is handled by the RMP Motion Controller. The RMP sends commands to the drive to move the motor in a controlled manner while continuously monitoring feedback signals such as limit switches, encoders, or sensors via the drive or other I/O devices.

The master evaluates these signals to determine when homing is complete and sets the position reference accordingly.

Note

While Master-Based Homing offers flexibility, we recommend using Drive-Based Homing or Custom Homing. Master-Based Homing is susceptible to EtherCAT network latency, which may impact precision.

🔹 How to Master-Based Home?

Before trying to perform a homing routine, please revise the following:

1. Define a clear Safety Zone
2. Make sure that the motion parameter values and user units under the motion and tuning tab are configured properly.
3. Set the hardware pos/neg limit actions to STOP under the limits and actions tab.
4. Select a homing method

RMP Master-Based homing can be done via the following:

• RapidSetupX

• RapidSetup

• RapidCode API See the Axis Homing Section methods.

RMP Homing Parameters

• State: Either “NOT HOMED” or “HOMED” indicating it has successfully completed the selected homing method.
• Method: Select the homing method that is best suited for your machine.
• Behavior: Select the RSIAction you wish to use during Master-based homing completion.
• Offset: After the homing limit is reached, the axis will move ahead or back the number of revolutions specified by Home Offset (e.g., if Home Offset is 10, the axis will move 10 rotations ahead, and if Home Offset is -5, the axis will move 5 rotations back).
• Move to Zero: Check this box if you want to move to position 0 after homing. (Scaled by User Units)
• SlowVelocity: Sets the velocity used for final homing/stage3.
• Cancel Button: Cancels the homing request and disables the motor.
• Home/Start Button: Enables the motor and begins executing the selected homing method.

Warning

The only situation HomeDeceleration is used is if the maximum homing travel is exceeded and a switch is never hit. StopTimeSet is used for the pos/neg limit switch deceleration.

🔹 Homing Methods

Warning

RSI's implementation of the DS402 homing routines deviates slightly from the standard, incorporating modifications to minimize final momentum. Refer to the diagrams below for a detailed representation of the behavior.

Note

The axis will travel at a specific speed in each stage. You can set velocity for a stage using:
HomeVelocitySet(RSI::RapidCode::RSIHomeStage homeStage, double velocity)

or set all four stages to the same velocity using:
HomeVelocitySet(double velocity)

Improved DS402 Implementations (100-137)

Warning

Index Pulse methods are only available for AKD. New projects should only use 100-137. Methods 0-37 remain for backwards compatibility.

Note

These methods will trigger off of the Limits (STATUS BITS) and can be inverted in the motion controller.

(100) None (Default Setting)

(101) NegativeLimitSwitch RightIndex (102) PositiveLimitSwitch LeftIndex

(103) PositiveHome LeftIndex (104) PositiveHome RightIndex

(105) NegativeHome RightIndex (106) NegativeHome LeftIndex

(107) RisingHome LeftIndex PositiveStart (108) RisingHome RightIndex PositiveStart

(109) FallingHome LeftIndex PositiveStart (110) FallingHome RightIndex PositiveStart

(111) FallingHome RightIndex NegativeStart (112) FallingHome LeftIndex NegativeStart

(113) RisingHome RightIndex NegativeStart (114) RisingHome LeftIndex NegativeStart

(117) NegativeLimitSwitch (118) PositiveLimitSwitch

(119) PositiveHome NegativeMomentum (120) PositiveHome PositiveMomentum

(121) NegativeHome PositiveMomentum (122) NegativeHome NegativeMomentum

(123) RisingHome NegativeMomentum PositiveStart (124) RisingHome PositiveMomentum PositiveStart

(125) FallingHome NegativeMomentum PositiveStart (126) FallingHome PositiveMomentum PositiveStart

(127) FallingHome PositiveMomentum NegativeStart (128) FallingHome NegativeMomentum NegativeStart

(129) RisingHome PositiveMomentum NegativeStart (130) RisingHome NegativeMomentum NegativeStart

(133) Negative Index (134) Positive Index

(135) Current Position

(136) Negative Hard Stop (137) Positive Hard Stop

Old DS402 Implementations (0-37)

Note

These methods will trigger off of the Switch (Dedicated I/O) and can be inverted in the controller. Some Drives may support inversion.

Value: 0 - No Homing (Default Setting)

Value: 1 and 2 - Homing with the negative/positive limit switch and index pulse

Value: 3 and 4 - Homing on the positive home switch and index pulse

Value: 5 and 6 - Homing on the negative home switch and index pulse

Value: 7 and 8 - Homing with the home switch input signal and index pulse starting in the positive direction

Value: 9 and 10 - Homing with the home switch input signal and index pulse starting in the positive direction

Value: 11 and 12 - Homing with the home switch input signal and index pulse starting in the negative direction

Value: 13 and 14 - Homing with the home switch input signal and index pulse starting in the negative direction

Value: 17 and 18 - Homing with the negative/positive limit switch

Value: 19 - Homing on the positive home switch

Value: 21 - Homing on the negative home switch

Value: 23 - Homing with the home switch input signal starting in the positive direction

Value: 25 - Homing with the home switch input signal starting in the positive direction

Value: 27 - Homing with the home switch input signal starting in the negative direction

Value: 29 - Homing with the home switch input signal starting in the negative direction

Value: 33 and 34 - Homing on the positive/negative index pulse of the current position

Value: 35 - Homing with the current position

Value: 36 and 37 - Homing on the negative/positive hard limit

📜 Sample Code

• C#

        axis.HardwareNegLimitActionSet(RSIAction.RSIActionSTOP); // Neg Limit action set to STOP.
        axis.HomeMethodSet(RSIHomeMethod.RSIHomeMethodImprovedFALLING_HOME_NEGATIVE_START_POSITIVE_MOMENTUM); // Set the method to be used for homing.                  
        axis.HomeVelocitySet(Constants.VELOCITY);                // Set the home velocity.
        axis.HomeSlowVelocitySet(Constants.VELOCITY / 10);       // Set the slow home velocity. (used for final move, if necessary)
        axis.HomeAccelerationSet(Constants.ACCELERATION);        // Set the acceleration used for homing.
        axis.HomeDecelerationSet(Constants.DECELERATION);        // Set the deceleration used for homing.
        axis.HomeOffsetSet(0.5);                                 // HomeOffsetSet sets the position offset from the home (zero) position.
   
        axis.Home();                                             // Execute the homing routine.
   
        if (axis.HomeStateGet() == true)                         // HomeStateGet returns true if the Axis is homed.
        {
          Console.WriteLine("Homing successful\n");
        }
   
        axis.ClearFaults();                                      // Clear faults created by homing.
        axis.AmpEnableSet(false);                                // Disable the motor.