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Manuals/Bode.md
2025-07-10 09:31:54 +02:00

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How to Bode with TwinCAT

Requirements

  • PLC
  • EL7XX Servodrive
  • PC
  • Visual Studio Code 2017
  • TwinCAT 3
  • eXtended Automation Runtime (XAR)
  • Remote Desktop Connection
  • Patience

Introduction

The goal is to get a Bode plot of an NC Axis connected to the EL7XX Servodrive. This documentation should enable you to perform a Bode plot and tweak the settings for better performance.


Steps

1. Setup a Standard TwinCAT Project

  • Ensure your target axis is correctly set up.
  • You should be able to jog the axis.

2. Verify Target Version

Make sure your target build version is 4026.67. If not, see How to upgrade.


3. Enable TcComObjects

Go to your TwinCAT project and select the following options in TcComObjects:
TcComObjects


4. Add Dynamic Container for Oversampling

(Not available with EL7211)

  • Navigate to I/O → Devices
  • Right-click on Device 1 (assuming your axis is mounted here)
    Dynamic Container
  • Select: Append Dynamic Container
  • Agree to all pop-ups

5. Decrease PLC Cycle Time to 250 µs

PLC Cycle Time

6. Set NC Motion Task to Use PLC Cycle

NC Motion Task

7. Disable Encoder LP Filter

Disable the low-pass filter for the encoder (speed and/or position, depending on your measurement focus). Then Download the settings.
Encoder Settings


8. Enable the Axis in Main Visualisation

Open the main visualisation and enable the axis as if you were going to jog it.


Open New Bode Project

9. Open TwinCAT or Visual Studio Code

Open Bode Project

10. Select Bode Plot

Bode Plot Options

11. Set Target in Bode Properties

  • Target ID: Set to the TwinCAT route of your PLC
  • Axis ID: Set to the ID of the axis in your TwinCAT project
    Target Settings

12. Adjust Settings for Performance

Tune the settings to get the best performance from the EL7XX.
Bode Settings


13. Start Measurement

Start Measurement

14. View Your Measurements

Measurements will appear under Bode Plot.
Measurement Location


Display Options

1. Navigate to the Bode Project

  • Click on the project to open display options
    Extended View Navigation

2. Enable Extended View

  • Set Appearance / View Detail Level to Extended
    Extended View

3. Customize Measurement Appearance

Select individual measurements and adjust their appearance in the Properties panel.
Appearance Settings