EPOS4 / IDX: Checking Controlword reaction by the Statusword

Topic:

• How can I check if the EPOS4 is already in "Enable" state?
• How can I ensure or check that the EPOS4 has reacted on an updated Controlword command and is ready for the next action?

Situation:

Chapter "7 Device Programming" of the "EPOS4 Application Notes Collection" describes the required general sequence of the configuration and commanding of the different operating modes. There are sometimes updated commands of the Controlword required to change the EPOS4 state to be ready for the next sequence steps. If a master commands the steps (resp. updates of the Controlword) too quickly before the EPOS4 is able to react, it might happen that subsequent commands might not be processed like expected.  

Solution:

All the following information is valid for the EPOS4 and IDX as well.

The EPOS4 minimum bus cycle time and update rate is 1 ms. Depending on the command and system state it might be possible that processing of an updated command (or Controlword) lasts even longer than 1 ms. Instead of inserting delays by the master's command queue, it is recommended (esp. in case of fast commanding real-time masters) to check the content of the Statusword (Object: 0x6041) after each updated Controlword (Object: 0x6040) before the next command is processed.

Example: EPOS4 sequence for enabling

Additional note:

The attached PDF holds the above recommended "Enable" sequence plus some more details concerning handling of the "Profile Position Mode" in case of updated "Target Position" (0x607A) commands or checking if the "Target Position" is reached.

Cross Reference:

•  Chapter "7 Device Programming" of the "EPOS4 Application Notes Collection"