Re: second computer for DRO readout

[Paul <paul.corner-at-tesco.net>]

Hi Alex

EMC normally reads the encoder position at one millisecond intervals before 
running the internal trajectory calculations. To add the DRO feedback from a 
slow non-realtime source such as a TCP/IP network would negate the reasons 
for running a realtime operating system.
Whilst there are low latency "realtime" network drivers available, these 
still do not have the response times required - The time involved in getting 
everything to work reliably would be better spent on wire wrapping a DRO 
board.

Regards, Paul.


On Friday 20 Dec 2002 4:34 pm, alex wrote:
> Can the DRO input be done into another machine, a DOS machine ,
> for example? I think this was already accomplished, and DOS machine can
> capture encoder data into the parallel port.
> This DOS machine can be networked to the EMC Linux machine over the
> Ethernet (WATTCP). Then data in a DOS machine can be written into the
> socket and Linux Emc can read them from the socket at the Ethernet rate (
> no RT required), similar its is done now for the ISA card, and used for a
> closed loop control of the steppers.