On 15-11-2010 15:52, Thorsten Schnebeck wrote:
Am Montag, 15. November 2010, um 15:23:15 schrieb Maarten Burghout:
Unfortunately, I'm still trying to establish PDO-exchange between
my master and a Beckhoff FB1111-014X SPI slave.
Main problem seems to be the absence of pdo-entries in the slave
configuration. Output of "ethercat cstruct":
Hi,
just as a side node. You know that you need a µC controlling the
FB1111-014X SPI slave that runs Beckhoffs slave sample code or your
own adaption of the ethercat protocol stack? Only the
32-BIT-IO-FB1111-0142 type runs without further µC assistance.
Does this also hold when Device Emulation (see notes at AL control
register 0x0120) is enables, like I did (and didn't mention in my
earlier message)?
Our result was that for a low latency control loop with up to 20KHz
the SPI-slave is too slow. We need too much time to get the ethercat
frame from the slave controller to the µC (dsPICF, 40Mips). Now we
check a control system with a stack of FB1111-0142 but I have no
results so far :-)
At this moment, we are aiming for a 1kHz control loop. Given a PWM value
represented by a 16-bit word, and an encoder value in 32-bit
representation, I'd think SPI (running at 5MHz at the moment, could be
increased to 20MHz if necessary) would be able to handle that.
HTH
Thorsten
Kind regards and grateful for your answer,
Maarten Burghout
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