Re: devGpib problem

[Ralph Lange <Ralph.Lange@bessy.de>]

Using VLAN technology (what most larger sites do nowadays), your 
host-based IOC can define multiple logical interfaces on different VLANs 
on one physical NIC. This does not require additional hardware and 
separates the controls (CA) network(s) from the instrument (device) 
network(s) logically, while still using the same wire.
I would recommend at least this level of separation, as it adds a layer 
of insulation between the instruments and the wild west on-site network.
People have had bad experiences with stupid network enabled devices 
(even PLCs) acting weird or crashing caused by things on the network.
Also very useful if you don't want to install all these countless 
Windows patches on your hi-end scopes (since this breaks them once in a 
while), but your official IT department policy doesn't allow unpatched 
Windows systems on visible networks.

Ralph


On Fri 16 Jul 2010 12:24:57 Pete Jemian wrote:
> Some parts of APS have these separated but most put them together on 
> the same subnet.
>
> On 07/16/2010 10:58 AM, emmanuel_mayssat@lynceantech.com wrote:
> > On 18:17 Thu 15 Jul     , Mark Rivers wrote:
> > > Shifu's device is a TCP/IP power supply, talking a simple ASCII
> > > protocol.  When talking to the device it usually responds quickly, but
> > > occasionally the responses are very delayed.  Whether this is due to 
> > > the
> > > device or to the APS network is not clear, but in any event sometimes
> > > the response does not occur until after the 2 second timeout specified
> > > in the devGpib file.  However, the device does appear to always
> > > eventually reply.
> >
> > I have similar problems with a few of my networked devices.
> > In my case, I believe this is due to broadcast packets.
> > A (logical or physical) point to point connection (device<->  IOC ) 
> > solve that problem.
> > I believe the broadcast packets are nothing less than the CA protocol 
> > itself ;-)
> > In a perfect world, one should have a network with OPIs and another 
> > network for controlled devices.
> > The IOCs are the bridges between both networks.
> >
> > At APS, are controlled devices and OPIs on the same net?