Is Ethercat supported?

HighFreq

We would like to use some linear axis that support ethercat, is it supported by duet3d?

In case it isn't is any of the following supported?

mega-ulink
mechatroniklink III

In case none of these are supported i guess voltage command + pulse can be used (it is i guess the most baasic control).

alankilian

@highfreq

I've never used it, but if I'm reading THIS DOCUMENT correctly, an EtherCat slave requires special hardware not present in the Duet ecosystem of boards.

• EtherCAT Slave Controller (ESC) and Process Data Interface (PDI)
The ESC is a chip for EtherCAT communication. The ESC handles the EtherCAT protocol in real-time
by processing the EtherCAT frames on the fly and providing the interface for data exchange between
EtherCAT master and the slave’s local application controller via registers and a Dual-Port-RAM
(DPRAM).
The ESC can either be implemented as FPGA (Field Programmable Gate Array) or as ASIC
(Application Specific Integrated Circuit). The EtherCAT frame is completely processed by the ESC,
and hence, the processing speed is basically the same for any EtherCAT slave. It does not depend on
the host controller performance. At the same time, the application on the host controller does not need
to process the Ethernet frame forwarding, and hence, the host controller resources are free to be used
by the slave’s application. The processing frequency of the host controller is defined by the host
application.Introduction
ETG.2200 EtherCAT and EtherCAT P Slave Implementation Guide I-11
The ESC processes EtherCAT frames on the fly and provides data for a local host controller or digital
I/Os via the Process Data Interface (PDI). Different ESCs might support different PDIs, most common
PDIs are: ESC.:
Up to 32 Bit digital I/O
Serial Peripheral Interface (SPI)
8/16-bit synchronous/asynchronous Microcontroller Interface (MCI)
With FPGA: specific on-board-bus (Avalon on Altera devices resp. OPB on Xilinx devices)
Process data and parameters are exchanged via a DPRAM in the ESC. To ensure data consistency
appropriate mechanisms are provided by the ESC hardware (defined by the EtherCAT protocol, e.g.
SyncManager (SM), chapter 1.3.4).
In case of an FPGA implementation, the ESC is realized as IP core to enable EtherCAT
communication and application-specific functions. The EtherCAT device functionality is configurable
with regard to the EtherCAT features such as number of Fieldbus Memory Management Units
(FMMUs) and SyncManagers, DC support, PDI (chapter 2.3).
FPGA implementations are at option in two ways. One way is integrating ESC and a soft core µC on
the FPGA. As PDI the FPGA on-board bus is then used. Another option is using the FPGA solely for
the ESC functionality and connecting an external µC via µC/SPI, s. Figure 3

Looking at those other two protocols quickly, I do not think either of them can be easily supported by the Duet ecosystem.

Also, the Duet does not provide a "step and direction" or Analog command input source for motion.

HighFreq

@alankilian Are you sure Duet doesn't provide step and direction? I read a bit around and it looks like it is supported trough an external board.

droftarts

@highfreq Yes, Duet boards do provide step and direction, though how you do it depends on the board and the signalling voltage required.

The Duet 3 Mini 5+ supports two external drivers, with 3.3V single-ended signalling. The Duet 3 MB6XD supports six external drivers (with no on-board drivers) with 5V single-ended signalling. The Duet 3 MB6HC has no support for external drivers on-board. However, all Duet 3 mainboards support the Duet 3 Expansion 1XD boards over CAN-FD, which provides single ended or differential 5V signalling for one external driver. Multiple 1XD boards can be daisy-chained to support as many external drivers as you need.

Duet 2 WiFi/Ethernet has 3.3V signalling direct from the expansion connector, or a differential output signal of -3.6V to +3.6V, or 5V, with the Expansion Breakout Board. Alternatively, you can connect three external drivers to a DueX board, though signalling is 3.3V.

Ian

alankilian

@highfreq said in Is Ethercat supported?:

@alankilian Are you sure Duet doesn't provide step and direction? I read a bit around and it looks like it is supported trough an external board.

I do not believe that the Duet ecosystem has a way to control the system through a step and direction INPUT (commanded position).

it does have a way to generate step and direction OUTPUT signals to an external motor-control driver board.

I thought you were asking about commanding a Duet board through EtherCat (and others) so I assumed you meant you wanted to also control the Duet board by sending step and direction commands to the board.

I'm sorry for my misunderstanding.

Maybe if you could ask your question in a little more precise way you'll get a different answer.

My assumptions could be completely wrong!