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JimPanse

Labview RealTime as EtherCAT slave

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Hello Experts,

I would like to operate a Labview RealTime system (PXI) as EtherCAT Slave. The master system should be a Beckhoff control. Is it possible to operate the Labview RealTime system as EtherCAT slave?

Thanks in advance
 

 

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Well I know nothing about EtherCAT but I have some links that you've probably already found.

 

http://www.ni.com/white-paper/7299/en/

http://www.ni.com/white-paper/14140/en/

 

80 views isn't that much, there are many lurkers.  And there are people like me that opened it up to see if it was something I could help with, then I closed it because I couldn't.  Oh an there are some that just read every post so that it is easier to find the unread posts.

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Hello Experts,

I would like to operate a Labview RealTime system (PXI) as EtherCAT Slave. The master system should be a Beckhoff control. Is it possible to operate the Labview RealTime system as EtherCAT slave?

Thanks in advance

 

 

 

At the moment I don't think you can.

It is my understanding that EtherCAT requires the Slave ethernet interface to be more advanced, because it is the slaves that manages the us synchronization between nodes etc.

So in order to get a PXI chassis to be an EtherCAT slave a special network card would have to be used.

 

I think there was a third party library posted on NI.com that allowed you to interface the beckhoff modules, but I don't remember if it was also possible to use for this scenario.

 

/J

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NI have a selection guide for Ethercat and lists PXI as requiring additional hardware. That is before getting to propriety protocols.

 

I would highly recommend talking to you local NI rep. They will be able to give you definitive answers and may even allow you to use a card for a short period to see if it is suitable for your needs.

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Its not a trivial task.  NI doesn't currently support using RT to create EtherCAT slaves.  NI likely has the knowledge of how to do this if it possible (ex: 9144 is an EtherCAT slave) but there is no public info on how to create a custom EtherCAT slave.  You probably need to contact NI to get help and you probably also need to start looking hard at the EtherCAT slave requirements - http://www.beckhoff.com/english.asp?ethercat/et9000_et9200_et9300.htm - which I think you'll find will also require joining the EtherCAT working group, etc.

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Hello Experts,

I would like to operate a Labview RealTime system (PXI) as EtherCAT Slave. The master system should be a Beckhoff control. Is it possible to operate the Labview RealTime system as EtherCAT slave?

Thanks in advance

 

No, the only slave is the 9144, PXI is usually used as a master. Out of curiosity why would you want to use a PXI chassis as a slave? I normally see PXI has a high speed/throughput acquisition system unless veristand is involved. Is there a PXI-only feature you need which isn't supported by the 9144? If you don't need deterministic single-point data communication, does the beckhoff controller support other protocols?

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Hello and thanks for the help,

in the RT system several cameras incl. image processing are required. This is not possible with the 9144.

One imaginable solution could with Anybus X-gateway with Its Modbus RTU Slave / EtherCAT slave. Modbus under LabVIEW RT was supposed to work. What do you think?

Is there any other indirect solution?

 

Thanks in advance

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One reason why EtherCAT slave support isn't trivial is that you need to license it from the EtherCAT consortium. EtherCAT masters are pretty trivial to do with standard network interfaces and a little low level programming but EtherCAT slave interfaces require special circuitry in the Ethernet hardware to work properly. One way to fairly easily incorporate EtherCAT slave functionality into a device is to buy the specific EtherCAT silicon chips from Beckhoff and others which also include the license to use that standard. However those chips are designed to be used in devices, not controllers so there is no trivial way of having them be used as generic Ethernet interfaces.

 

That makes it pretty hard to support EtherCAT slave functionaility on a controller device that might also need general Ethernet connectivity, unless you add a specific EtherCAT slave port in addition to the generic Ethernet interface, which is a pretty high additional cost for something that is seldom used by the majority of the users of such PC type controllers.

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Yeah I'd expect something like this (http://www.ethercat.org/en/products/92F6D9A027D54BABBBEAFA8F34EA1174.htm) to be right right answer, but I can't find one for PXI(e).

 

Modbus is not a particularly fast protocol and its also not that easy to use (there is only one data type). Do you have performance constraints for how fast you need to move data around or what the latency should be like?

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http://www.ethercat.org/en/products/92F6D9A027D54BABBBEAFA8F34EA1174.htm

 

In prinzipell it would be the right way. The PCI Interface could i solve with LabVIEW RT for desktop. But I dont think, there is a driver for the card that works under pharlab ets???

 

The latency is in the range of 10 ms. The latency period should be constant. However, the jitter should be no greater than 100 µs. Can I achieve this with Modbus TCP? Or is there a other faster RT interface from Labview RT to  a Beckhoff control?

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Throughput is about 128 bytes per message.When it comes, it should be an industry-standard solution.

 

Another approach would be a multi-master system. With the EL6692

 

http://www.beckhoff.de/default.asp?ethercat/el6692.htm

http://www.ethercat.org/de/products/E2DC6EE8DB5D4740BE8A0E4FCA61A309.htm

 

EtherCAT bridge terminal probably can communicate deterministically two EtherCAT Master. Is that right? Then I could operate the LV RT target as EtherCAT master.

Edited by JimPanse

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I like the solution with the Mutltimaster EtherCAT systemIt also enables synchronisation of the distributed clocks.

A LabVIEW RT EtherCAT master and a Beckoff EtherCAT master. Between the Bridge Terminal EL6692.

 

According to

http://forums.ni.com/t5/Industrial-Communications/LabVIEW-ECAT-Master-communication-problem-with-a-third-party/td-p/3045981

 

log it to work.

 

Are there things that speak against it?

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