CODESYS - the IEC 61131-3 automation software

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PostPosted: Thu Jun 07, 2018 3:46 pm 
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Posts: 12
Dear all,

I am doing a project which needs control position of several servo motors. To be more detail, they are EtherCAT slaves when I connect them to PC (run SoftMotion Realtime).

I tested separately each servo motor with function block SMC_FollowPosition as following:
Sine signal --> Get each point of Sine signal in every 5 ms --> set this point to Position of SMC_FollowPosition. In this case, servo motor operate smoothly and I checked set position and actual position, which are very good result.

However, When I connect 6 pieces servo motor in "LINE" topology with the same trajectory. The actual position of these motor is very different, and actual position did not track to set position. In EthercatSoftMotion Master, I realized that there were errors "Lost synchronicity" and "hardware realtime problem".

Does anyone know how to fix this problem? Please help me, I am very appreciated.

Best regards,
Mr. Phuc


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PostPosted: Thu Jun 07, 2018 5:17 pm 
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Joined: Mon Sep 05, 2005 9:42 am
Posts: 2760
Hi,
are you using SoftMotion RTE as plc with enabled distributed clocks on the SoftMotion Ethercat Master?
This is mandatory to have for this.
How is the jitter on the ethercat Task ( = Motion Task)? -> check with the task monitor when you are online

BR
Edwin


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PostPosted: Fri Jun 08, 2018 3:32 am 
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Posts: 12
Edwin Schwellinger wrote:
Hi,
are you using SoftMotion RTE as plc with enabled distributed clocks on the SoftMotion Ethercat Master?
This is mandatory to have for this.
How is the jitter on the ethercat Task ( = Motion Task)? -> check with the task monitor when you are online

BR
Edwin


Hi Mr. Edwin,

I set EtherCAT task is cyclic with 5 ms interval, it's the same time with distributed clock of EtherCAT master SoftMotion.
In EtherCAT task, I call Motion Task (MAIN in attached picture), which implements motion blocks such as: MoveAbsolute, SMC_FollowPosition.

I set priority "0" for EtherCAT task, and the jitter time of this task is 13500 us.

Please kindly help me if you see any problems in my configuration or hardware (I use IndraDrive of Bosch Rexroth)

Best regards,
Mr. Phuc


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PostPosted: Fri Jun 08, 2018 4:43 am 
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Joined: Mon Sep 05, 2005 9:42 am
Posts: 2760
Hi,
please do a reset on the taskmonitor - by rightclick on the Ethercat line-- to see clean min/max values.
the most important are the last two Min / Max Jitter should be <+/+40us

BR
Edwin


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PostPosted: Fri Jun 08, 2018 5:53 am 
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Joined: Tue Mar 13, 2018 8:26 am
Posts: 12
Hi Mr. Edwin,

I've just checked. The average value of min/max jitter is around 17 us, but sometimes these values exceed +- 20us as attached picture.
What should I do to fix this problem? In my opinion I have to increase cycle time of task, or Does EtherCAT master card have problems? ( I use Intel 217, and install driver manually in Codesys directory).

Best regards,
Mr. Phuc


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PostPosted: Fri Jun 08, 2018 6:00 am 
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Joined: Mon Sep 05, 2005 9:42 am
Posts: 2760
Hi,
no, everything seems ok from my point of view.
Do have bought a license for the Softmotion RTE(has nothing to do with the sync fault - just administrative question)

BR
Edwin


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PostPosted: Fri Jun 08, 2018 7:40 am 
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Joined: Tue Mar 13, 2018 8:26 am
Posts: 12
Hi Mr. Edwin,

Now, I use trial version which works within 2 hours. After finishing testing, I will buy license via Store Codesys.
Is it OK to test with trial version?

BR,


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PostPosted: Fri Jun 08, 2018 10:05 am 
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Joined: Mon Sep 05, 2005 9:42 am
Posts: 2760
Hi,
sure, should work for testing without problems.

BR
Edwin


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PostPosted: Fri Jun 08, 2018 10:44 am 
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Joined: Tue Mar 13, 2018 8:26 am
Posts: 12
Hi,

Now I don't know where this problem come from. I tested with single servo motor, and also 6 virtual servo motors. The result of this case is very good, actual position always track to set position which I set through SMC_FollowPosition.

However, when I test with 6 pieces of real servo motors, actual position cannot track to set position.
Could you recommend solution for this problem?

BR,
Mr. Phuc


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PostPosted: Fri Jun 08, 2018 12:25 pm 
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Joined: Mon Sep 05, 2005 9:42 am
Posts: 2760
Hi,
hm.. hard to say without checking it online on your devices.
How could we proceed with this?
CODESYS store - my question.
BR
Edwin


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