LinuxCNC whit Sercos II

Hi, I needed help with a problem that I have.

I want to build a plasma cutting CNC and I want to use a servo motor and Allen Bradley units that use the Sercos II interface.

Can you configure linuxcnc with Sercos II?

I thought about using a Sercos II master as a PCI card that is in the market.

I hope someone can help me, greetings.

Thanks for responding but the drivers use Sercos II not Sercos III interface.
This interface is communicated by optical fiber and not by Ethernet cable, that is the problem.

Greetings.

Hi!

I've made my LinuxCNC work with SERCOS II (fiber optics). Now my machine (Trumph TC2000R) has been working well for almost a year, and I'm positive that there are no bugs.

My steps were:
1. Bought a cheap SERCOS II PCI extension card from Beckhoff (FC7501, ~$150), plugged it into the free Beckhoff 3 suite
2. Sart sniffing the digital signals using my $10 logical analyzer from aliexpress
3. Set up all drives using the Beckhoff, so I have a full log of startup messages and synchronization process
4. Parsed it
5. Captured and analyzed a lot of command messages, so now I understand how messages are built
6. Made a dummy STM32(~$200) device, which takes a SERCOS message from the Ethernet and transmits it into the IO pin. You don't even need a real-time ethernet card, because SERCOS II is synchronous and the period between timings is fixed. My module even operates in user-space!

To sum up, the whole Sercos II protocol was re-implemented, and I developed a Linuxcnc module that prepares a message. The code is available here: github.com/arabel1a/sercos2-linuxcnc

However, it is more proof-of-concept than a plug-and-play solution. The main drawbacks include:
1. You need a capture synchronization messages (first few seconds after startup), I wasn't able to reimplement this stage.
2. STM32 hardware code (which just sends a message received on ethernet) can't be published due to some legal reasons.
3. The code is a bit messy, and not any configuration is supported. I used my drive in velocity command mode with feedback other modes are untested.

Anyway, my machines have been working for almost a year, and you can reproduce it with the code above. It costed me <$500 and a nine months of work, which is much less than a brand new NC unit from Trumph ($10,000!) If someone would be interested in making a more user-friendly solution, I would be honored to assist you -- contact me via github.

Hi arabel1a, 

Very interesting. I have some Sercos II drives myself.

I'm thinking the STM32 came with the Sercos software stack, saving a lot of work. Do you have a link to the device you used?

Any thoughts on driving the FC7501 card directly? It has a well documented PLX 9052 PCI interface on one side, and the mysterious SERCOS ASIC on the other side.

Did you ever find any docs for the Sercos ASIC? The datasheet is available, but references a programming manual which I can't find.

I wrote a quick PCI driver for QEMU which presents itself as a fake 7501 card. Windows seems happy with this and auto loads the driver. My thought was, this fake driver could be tied to a second driver on the Linux side attached to a real 7501, allowing the command stream across the PCI bus to be captured. 

Although without the manual, it's probably more trouble than it's worth. Looking forward to hearing more about the STM32 you used.