Machine security and safety

> > Ethernet has also crossed my mind as a good option for this - however, I
> > don't think anyone in their right mind would attach a machine tool to an
> > Ethernet that had any possibility of being "hacked" from outside - or
> > indeed to any intranet where the behaviour of the network might be
> > adversely affected by the guy in the next cube playing the latest video
> > game, or whatever.
>
> You can use local addresses for the critical nodes. Such as 10.10.1.x
> These net addresses will not be transported through routers, so noone
> from the outside can see their traffic or send packets to them.

Assuming the routers are configured properly, and not transfering packets
between a bunch of pc's on that subnet and one external IP address.

In reality, any machine tool connected to any computer that is connected
to a network should be considered insecure.

And any cnc machine (at least one that is out of e-stop) should be
assumed to be able to start moving at any time and crush any body
parts in its path, due to security breaches, bugs, glitches, encoder
failure, or simply bad luck. So why do I never remember this when I
lean into funny positions around the eztrak mill to eyeball the
placement of a center drill onto a pre-existing feature? In fact I
not only ignore the risk, I reach up and slowly turn the jog wheel to
perfect the placement, which kind of precludes locking out power to
the axis drives. Is there a safer alternative? I guess there are
those centering microscopes, but even there you are leaning very close
to the machine.

Chris Stratton

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Christopher C. Stratton
Engineer, Instrument Maker, and Horn Player
ccs@... 617 628 1062
http://web.mit.edu/~stratton/www/brassbuild.html