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Ethercat 3rd Party Device Profile XML File not complete

Hi Sébastien, 

 

The XML file actually didn't contain the torque mode PDO. I created it based on page 61 of the manual. The manual doesn't specify what the data type of Torque actual value should be so I guessed.

 

 

The attached should switch the motor into torque mode and start streaming data. 

 

 

 

 

 

Jesse Dennis
Engineer
INTP
Message 11 of 29
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You are amazing.

I'll take a look at this at work tomorrow.

Thank you very much.

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Message 12 of 29
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OK, If I understand :

 

- you have deleted the two unused devices

- you have added the wanted PDO

- you have moved the sm tag to the current active PDO

- the SDO are not part of the xml part, the only way to modified a SDO is using the method node in your example.


Is that correct?

Why do you put the scan engine in configuration mode at the end of you RT VI ?

 

It is clear now, can I ask you how you know about that ?

Is it because you are from NI, or because you know where to look for documentation ?

Have you a link which explain in details the functionnalities of the NI Ethercat schema + associated nodes ?

 

Thanks !

It's a Kudo for you !

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Message 13 of 29
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You understand correctly. 

 

I leave the scan engine in configuration mode as a best practice. 

 

The XML schema is recorded in the Ethercat specification: 

 

http://www.ethercat.org/pdf/english/ETG2200_V2i0i0_SlaveImplementationGuide.pdf

http://www.ethercat.org/en/downloads/downloads_6A46D45EA33C47ECB2BB2686BBA963EC.htm

 

Unfortunately I can't pass those documents on. 

Jesse Dennis
Engineer
INTP
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Message 14 of 29
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Hi Jesse,

 

After a lot of tests, it's a fact, it's impossible to do Ethercat with a CompactRIO above 1 ms....(my client is very very very angry about that).

 

A performance PXI is to expensive for my application.

 

What about a classical pc, Core i7 or Core i5,  formatted as a RT pc with NI tool (Phar Lap if a remember) ?

 

Thanks

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Message 15 of 29
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Hi Sebastien, 

 

CRIO can go faster than 1ms, expecially the new linux targets. 

 

However, what are your exact requirements? Do you have code I can look at? 

 

Depending on what you are doing we may be able to speed it up with the raw data API. 

 

To answer your question, it just is question of computing power on the network stack. If you just are transfering data, the CPUs with the higher clock speed will probably be faster. 

 

Pharlap is the OS. 

 

Jesse Dennis
Engineer
INTP
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Message 16 of 29
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I have a fresh 9074, below 1ms, it hang, crash and everything...
Which compactRIO able to do Ethercat below than 1ms are you describing ?
M'y requirements are : command 3 motor drives with Ethercat, and get position and torque at a rate of 125 us trough Ethercat.
What is the raw data api ?
With a core i7 formated as a real time target, Which Ethercat rate can I expect ?
Thanks
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Message 17 of 29
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Hi Sebastian, 

 

1) With a 9074 I would believe you do not get below 1ms with any appreciable amount of data. I think hinted at this before, but it is just because the processor on the 9074 is so slow. You probably can do this project with a more powerful cRIO.  

 

2) I was using a 9025. The 9068 should definitely get above 1khz and would probably meet your application needs. Having a dual core target helps a lot.

 

3) Can you look at your project and look at the amount of bytes you need to read and write? The loop rate you can get will be directly affected by the amount of data you are reading on your block diagram. If you decrease the IO you are reading in your program you will find the speed you can achieve increase proportionally. 

 

4) The raw data API is something that can speed up the data transfer on a 9144. I think you are using just third party hardware though,it may not help. 

 

5) We can estimate it using some benchmarks. The PXI 8106 is 10-20x faster than the 9074. 

 

The 8106 has a 2.1GHZ dual core, the I7 has a 3.6Ghz quad core. So I would expect the I7 to be ~30x faster than the 9074 without changing the default settings.

 

If you have an I7 handy, I think it will work for your application. If moving to an RT target will impact your project, I would look hard a the 9068. 

 

 

Jesse Dennis
Engineer
INTP
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Message 18 of 29
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Hi Jesse,

Thank you for these answers.

To answer you, here is the list of the variable we use for this project :

Variables.png

 

Do you think a 9068 would be able to exchange all this list a variable in a cycle time of 125µs ?

 

I think I would ask to a NI commercial if it's possible to lend us a 9068.

 

Thank you very much,

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Message 19 of 29
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Hi Jesse,

Sorry for insisting, can you look at my LV project and tell me if a 9068 woill be able to run all these Ethercat variables at 125µs ?

Thanks

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Message 20 of 29
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