Teach & Touch Up Robot Points via HMI

The Power of PLC-Based Robot Control

In a typical factory environment, touching up robot points often requires connecting a laptop, retrieving a specialized teach pendant, and navigating robot-specific software. Integrating the robot into Allen-Bradley PLCs using Add-On Instructions (AOIs) eliminates these extra tools by storing positional data and executing moves directly inside the Logix controller.

Key Benefits of AOI Integration:

• HMI-Based Touch-ups: Maintenance personnel can recalibrate and teach positions using an HMI/PanelView without taking the robot offline or using a teach pendant.

• Direct TCP Command Moves: Programmers can command precise Tool Center Point (TCP) positions directly in millimeters and degrees straight from ladder logic.

• Centralized Data Storage: Positional arrays are saved inside PLC Controller Tags rather than locked inside the robot controller.

Direct Position Motion with Move MM Blocks

Using the Move_MM Add-On Instruction, you can send absolute coordinates directly to a 400 mm Scara robot without pre-teaching positions in the robot controller.

Executing Direct Moves:

1. Enable the Move_MM instruction block in your Studio 5000 ladder logic routine.

2. Enter target values for the TCP:

   • X Axis: Linear distance forward (e.g., 0 mm or 200 mm).

   • Y Axis: Linear lateral distance (e.g., 400 mm or 200 mm).

   • Z Axis: Vertical height displacement.

   • R Axis: Tool rotation angle (e.g., 45 degrees).

3. Trigger the move command to drive the robot to the specified coordinates.

4. Toggle arm orientation (such as Right-Hand vs. Left-Hand configuration) directly within the instruction parameters.

Storing Robot Points in PLC Controller Tags

To manage multi-point sequences, positional data is structured into User-Defined Data Types (UDTs) and stored as Controller Tag arrays within Studio 5000.

Point Array Structure:

An array tag (e.g., Robot_Points[X]) stores full coordinate data for each point location:

• X / Y / Z: Cartesian location values (in mm).

• R: Tool orientation angle (in degrees).

• Comment: Text string identifying the point (e.g., "Home", "Pick Position", "Place Position").

Rapid Point Teaching via PanelView HMI

By setting the robot controller to a free state with servo motors unpowered, technicians can manually position the arm and record real-time TCP coordinates directly into the PLC tag array.

Step-by-Step Point Teaching Workflow:

1. Free the Robot: Disable servo power to allow manual movement of the arm.

2. Read Real-Time TCP Data: Enable Get Positions on the PanelView to stream real-time motor feedback to the HMI display.

3. Teach Positions: Manually move the arm to each sequence location and press Teach to write TCP coordinates into the respective array index:

   • Index 0 (Home Position): Set the default rest position and press Teach.

   • Index 1 (Pick Position): Move the gripper to the physical pick point and press Teach.

   • Index 2 (Above Pick Position): Raise the Z-axis straight up to establish clearance and press Teach.

   • Index 3 (Above Place Position): Move to the drop-off area, adjust the R-axis rotation, and press Teach.

   • Index 4 (Place Position): Lower the arm into the target location and press Teach.

Replaying the Taught Sequence

Once points are saved into the PLC tag array, restore servo power to test and cycle through the taught locations:

1. Re-enable servo power from the HMI.

2. Step through the sequence using the PanelView replay interface:

   • Execute move to Home Position.

   • Advance to Pick Position.

   • Retract to Above Pick Position.

   • Traverse to Above Place Position.

   • Lower to Place Position.

   • Return to Home Position.