Position Motion Mode

Position Mode Configuration

Overview

In Position Mode, positions are sent to the controller using millimeters (mm) for translational movements (Surge, Sway, Heave) and degrees (°) for rotational axes (Yaw, Roll, Pitch). These values are represented as 32-bit floating-point numbers (float). Additionally, a "Belt" value for the 7th actuator can be included as a 32-bit unsigned integer (uint32) when required. Each value (whether float or uint32) is 4 bytes in size, and the total packet length is fixed at 36 bytes.

Data Structure

The position data is transmitted as follows:

• Translational Movements:

  • Sway: 4-byte float (in mm)

  • Surge: 4-byte float (in mm)

  • Heave: 4-byte float (in mm)

• Rotational Axes:

  • Yaw: 4-byte float (in degrees)

  • Roll: 4-byte float (in degrees)

  • Pitch: 4-byte float (in degrees)

• Optional Actuator:

  • Belt (7th actuator): 4-byte uint32 (only when needed)

• Placeholder:

  • Axis 8: 4-byte filler (e.g., 0000)

Packet Format

The complete data packet adheres to a fixed structure:

• Start Bytes: <252> <252> (2 bytes)

• Data Payload: 8 × 4-byte values (32 bytes total)

• Stop Bytes: <10> <13> (2 bytes)

This results in a total packet length of 36 bytes.

Handling Missing Values

If fewer than 8 values are used, the remaining slots must be padded with 4-byte placeholders (e.g., 0000) to maintain the fixed 36-byte packet length. The "Belt" value (7th actuator) is optional and only included when needed; otherwise, its slot is filled with a 4-byte placeholder.

Example Packets

1. Without Belt Value:

   <252><252><PSway><PSurge><PHeave><PYaw><PRoll><PPitch><0000><0000><10><13>

   • <PSway>, <PSurge>, <PHeave>: 4-byte float values (in mm)

   • <PYaw>, <PRoll>, <PPitch>: 4-byte float values (in degrees)

   • <0000><0000>: 4-byte placeholders for unused axes (7 and 8)

   • Total length: 36 bytes

2. With Belt Value:

   <252><252><PSway><PSurge><PHeave><PYaw><PRoll><PPitch><PBelt><0000><10><13>

   • <PSway>, <PSurge>, <PHeave>: 4-byte float values (in mm)

   • <PYaw>, <PRoll>, <PPitch>: 4-byte float values (in degrees)

   • <PBelt>: 4-byte uint32 value for the 7th actuator (Belt)

   • <0000>: 4-byte placeholder for unused Axis 8

   • Total length: 36 bytes

Summary

• Translational and rotational axes use 32-bit (4-byte) float values.

• The optional "Belt" actuator (7th axis) uses a 32-bit (4-byte) uint32 value, included only when needed.

• The packet always transmits 8 values (6 axes + optional Belt + 1 placeholder), totaling 32 bytes of data.

• Including start and stop bytes, the fixed packet size is 36 bytes.