Experimental Physics and
Industrial Control System

Ralph Lange <[email protected]> · Fri, 16 Jul 2010 13:23:10 -0400

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, [email protected] 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?

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System