FAQ - frequently asked questions and answers

Frequently asked questions are answered in this section in order to make it easier for you to work with TwinCAT 3 Bode Plot.
If you have any further questions, please contact our support (-157) and ask to speak to a drive expert.

 

  1. Can a machine get into a critical situation due to the Bode function?
  2. The Bode recording is started and nothing happens. What could be the cause?
  3. Can the Bode function be executed in U/F mode with an asynchronous motor?
  4. Can the Bode function be started with vertical axes?
  5. How does the Bode function behave on axes with play?
  6. Can the Bode function be used with "non-Beckhoff motors"?
  7. How many measuring points should be selected for a meaningful representation?
  8. Which measuring ranges are useful?
  9. Does the NC cycle time have an effect on the Bode representation?
  10. What system requirements must my PC fulfill?
  11. Are open source software components used in TwinCAT Measurement products?

Can a machine get into a critical situation due to the Bode function?

Yes, undesired movements may occur due to the occurrence of a mechanical resonance. A functioning emergency stop circuit is therefore essential.

 

The Bode recording is started and nothing happens. What could be the cause?

Possible causes could be:

  • The axis is not released.
  • There is a drive error. (This can be read in the TC_Drive_Manager).
  • Safety has canceled the release.
  • Lag error monitoring is active.

 

Can the Bode function be executed in U/F mode with an asynchronous motor?

No, the Bode function is possible only in controlled mode with feedback.

 

Can the Bode function be started with vertical axes?

Yes, but only in the "Velocity" mode. Note that "drifting " of the axis can occur here. If the axis is equipped with pneumatic assistance, this damping also affects the measurement result.

 

How does the Bode function behave on axes with play?

The mass may be metrologically decoupled. It is particularly important here to adapt the fundamental oscillation and measuring amplitude.

 

Can the Bode function be used with "non-Beckhoff motors"?

Yes, there is no manufacturer limitation.

 

How many measuring points should be selected for a meaningful representation?

10 to 20 per decade and of course more if necessary.

 

Which measuring ranges are useful?

5 - 500 Hz in Velocity mode, 50 - 3000 Hz in Current mode.

 

Does the NC cycle time have an effect on the Bode representation?

The measured values are transmitted in so-called dynamic containers. Furthermore, the oversampling method ensures precise reproduction of the measured values. The NC cycle time should be around </= 2 ms.

 

What system requirements must my PC fulfill?

At least TC3.1X4016.x XAE and the system requirements associated with it.

Are open source software components used in TwinCAT Measurement products?

Yes, various open source components are used.
Please see the information on the page Third-party components.