# Machine-Centric Robotics – Motion ST Programming **URL:** \ **Category:** How-To & Wikis\ **Tags:** machine-centric-robotics\ **Created:** [December 11, 2025, 11:42am UTC](https://community.br-automation.com/t/machine-centric-robotics-motion-st-programming/9347 "2025-12-11T11:42:57Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![kovarj](https://dub1.discourse-cdn.com/brcommunity/user_avatar/community.br-automation.com/kovarj/32/537_2.png) [@kovarj](https://community.br-automation.com/u/kovarj)\ **Post date:** [December 11, 2025, 11:42am UTC](https://community.br-automation.com/t/machine-centric-robotics-motion-st-programming/9347/1 "2025-12-11T11:42:57Z")
# **Machine-Centric Robotics – Motion ST Programming** * * * ## **Introduction** Machine-Centric Robotics (MCR) with Motion ST Programming provides a structured and flexible approach to robot motion control within B&R Automation Studio. This article explains the differences between ST application and robot programs, demonstrates a minimalistic demo project, introduces robotic path planning concepts, and provides detailed examples of ST commands and diagnostic tools. * * * ## **Agenda** - ST Application Program vs. ST Robot Program - Demo Project - Robotic Path Planning Basics - Examples and Diagnosis * * * ## **1. ST Application Program vs. ST Robot Program** #### **ST Application Program** ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/7/77279f85cbaa6d9639b08baca22b0a0c417808c1.png) - Used to **operate the robot**. - Inserted via toolbox into Automation Studio logical view. - Assigned to a CPU task class → runs in **cyclic context**. - Structure: - **Type file** : variable definitions, function blocks, parameter types, user-defined structures. - **Init program** : executed at PLC startup for initialization. - **Cyclic part** : typically contains a **state machine** (e.g., powering, homing, waiting, moving). - Stored in Logical View and compiled into binary with the Automation Studio project. #### **ST Robot Program** ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/3/3100a9b0c7703bcd0d61ed69410135e54fd8b4c3.png) - Contains **motion instructions** the robot shall perform. - Inserted via toolbox; executed by **Interpreter module** of Motion Chain. - Can include variable declarations (constants, PLC variables). - Main part executed by interpreter. - Stored on a **file device** (e.g., `CNC_PrgDir`) and can be updated **during runtime**. - Executed via: - Function blocks (e.g., `MC_BR_MoveProgram`) - mapp Cockpit. **Comparison Table** | **ST Application Program** | **ST Robot Program** | | --- | --- | | Contains the application logic e.g., used to operate a robot | Contains the (motion) instructions the robot shall perform | | Cyclic execution | Function block or mapp Cockpit | | Init/cyclic/exit parts | Interpreter-based | | Logical View storage | File device storage(CNC\_PrgDir) | | Compiled with AS project | Runtime updates possible | * * * ## **2. Demo Project** ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/c/c70e2c1f8af7b6e7e8c51023b3a94c7d3fee5407.jpeg) A minimalistic Automation Studio project was created for demonstration: - **Hardware** : APC3100 PLC with Powerlink interface. - **Robot** : Codian D4 1100 inserted via MCR template. - Required ACOPOS hardware. - Auto-generated Scene Viewer visualization. - Two file devices: - `Visualization` - `CNC_PrgDir` for motion programs. ### **Scene Viewer** ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/6/6777bbd8478f6400f15d89cf8a0aef0d4ee9445f.jpeg) - Standalone Windows application shipped with Automation Studio. - Connects via **OPC UA** to ArSim or hardware. - Visualizes robot motion. - Added manually: - **Path Tracker** : shows TCP trajectory. - **Positioner** : displays TCP position (and optionally orientation). ### **Frames** ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/b/bae46401b10130be6f37b93c89cf82b5c4f3914e.jpeg) - Object hierarchy and frame hierarchy define coordinate systems. - For this training: robot programmed in **base frame coordinates**. ### **Executing ST Robot Program** ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/1/1bcb3d8d2cee2d3c04a70ed1773113397cfee5ef.jpeg) - Specialized function blocks: - `MC_BR_MoveProgram` - `MC_BR_GroupPower` - `MC_BR_GroupHome` - Program name is referenced from the file device. * * * ## **3. Robotic Path Planning** ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/3/3d579cb05912c343a81f9c269be9c2818cfdf661.jpeg) ### **Motion Chain Basics** ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/2/279afb679480732a13cf72f438600151ab653e4b.jpeg) The motion chain consists of: - **Interpreter** : Reads ST program, generates motion commands. - **Geometric Path Planning** : Calculates TCP path. - **Dynamic Path Planning** : Applies speed profiles and axis limits. - **Set Value Sampler** : Generates cyclic setpoints for axes. **Execution Context** : - Set Value Sampler → cyclic task. - Other modules → background tasks. ### **Buffer Time** ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/1/10928167518940c47c6090d49a8c6f0878507dc5.png) * * * - Buffer compensates for CPU load variations. - Robot starts moving when buffer reaches minimum fill level. - Dynamic planning maintains lookahead. - If CPU load is high, buffer may drop → possible motion slowdown. ## **4. ST Commands – Overview and Examples** ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/7/7e5a4681379ca6bb07323b5ac1caa89aacc7dfd6.jpeg) Available ST commands are documented in Automation Studio Help under: **Motion Control → mapp Motion → mapp Robotics/CNC → Programming → G-code and ST overview**. * * * ### **Example 1: Absolute Positioning and Circular Interpolation** ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/a/a6643bfe56f2f987a23963380b7f808a02efbac7.png) ![Video1](https://europe1.discourse-cdn.com/brcommunity/original/2X/0/08302da1efeedb63b62b7343f29eaae24fac4ef2.gif) * * * ### **Example 2: Relative Positioning** ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/3/3a4267a5272c7e6809811060d981a30e16b63ac2.png) ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/4/4b8206528d86a999f8a8e2e27334b870661ef6d3.jpeg) * * * ### **Example 3: Joint Space Motion** ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/b/bcb7abd517c7cff848b7d8aec9b2d5ba678ea727.png) ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/3/35f132d705cbee39e9b3b6a303bd880f8623302a.png) * * * ### **Example 4: Feedrate and Rapid Motion** ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/7/718b40f6010cff52f89511957be9cbec500fb9c4.png) ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/7/7c552ad28441baa4c2f72eded324cbf3add3aee5.png) * * * ### **Example 5: Rounding Edges** ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/6/6e92eff617bf75f776489aeab448582d063f71c6.png) ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/7/7439cf66b7c898563e1fc6ed5093a3d2410f6c9b.png) * * * ### **Timing and Synchronization Commands** - Wait time ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/c/ca4b66793489730974d4c436e29b9f8b6a729a00.png) - wait end move ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/3/3265d13ec6a738da4dfac9a5b792962cf313ee02.png) - wait ALAP - wait until ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/5/5a2d1b136f999a46b6dfe5eb9bab95df2637990d.png) - wait until flash ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/b/bb50a94f7fdf8f82b2020b23669e6cd03ce13a06.png) - do path synch ![image](https://europe1.discourse-cdn.com/brcommunity/original/2X/d/db97381425216d7e5fad42bd0785bd7c1e61be4c.png) * * * ## **5. Diagnosis Tools** - **Scene Viewer** : Visualize robot motion. - **Logger** : Check for errors or unexpected behavior. - **Block Monitor** : Shows which program part is currently sampled. - **Interpreter Monitor** : Indicates which part was processed. - **Override** : Execute program slowly for debugging. * * * ## **Summary** Motion ST Programming provides a structured approach to robot control in Automation Studio: - ST Application Programs handle robot operation logic. - ST Robot Programs define motion sequences and can be updated at runtime. - Robotic path planning uses a motion chain with buffering for smooth execution. - A wide range of ST commands enables precise control of motion and timing. - Diagnostic tools simplify troubleshooting and commissioning. ---
**Author:** ![kovarj](https://dub1.discourse-cdn.com/brcommunity/user_avatar/community.br-automation.com/kovarj/32/537_2.png) [@kovarj](https://community.br-automation.com/u/kovarj)\ **Post date:** [December 11, 2025, 11:43am UTC](https://community.br-automation.com/t/machine-centric-robotics-motion-st-programming/9347/2 "2025-12-11T11:43:02Z")
Unlisted on December 11, 2025, 11:43am UTC ---
**Author:** ![kovarj](https://dub1.discourse-cdn.com/brcommunity/user_avatar/community.br-automation.com/kovarj/32/537_2.png) [@kovarj](https://community.br-automation.com/u/kovarj)\ **Post date:** [December 11, 2025, 12:28pm UTC](https://community.br-automation.com/t/machine-centric-robotics-motion-st-programming/9347/3 "2025-12-11T12:28:06Z")
Listed on December 11, 2025, 12:28pm UTC