Experimental Physics and
Industrial Control System

Dave Reid <[email protected]> · Wed, 16 Dec 2009 15:42:01 -0800

Hi Nick...

Here at the University of Washington Medical Center Cyclotron, we decided 4

years ago, at a brainstorming session in Geneva, to move away from anything VME.

 Our idea was to use the ethernet as a field bus. We hadn't invested too many

resources into VME at that time, and to us, it just seemed like that was a dead end.

We decided to go with multiple soft IOC's, each running on their own Linux

boxes. We use the same basic model of Linux-based PC's for running both IOC's

and EDM displays. This way we save money on our inventory of spares.

For digital I/O, we mostly use the Modicon Quantum PLC, with the ethernet

communications board. We were already using these PLC's, so this wasn't a big

financial investment for us. We program the ladder logic using the NXT

software, and communicate with the PLC from EPICS using Mark River's Modtcp

package to read back inputs and coils, and to make requests.

For analog I/O, we use ethernet-based Acromag I/O boards, which we also

communicate with using the Modtcp package.

We do have a few Acromag I/O combo boards that do both analog and digital I/O,

and we use these for controlling modular subsytems, such as the Power Supply for

our main Cyclotron coil.

We are also using the Agilent GPIB gateways for controlling various Power

Supplies. We communicate with these using Asyn.

For RS-232, we are using the Moxa I/O boxes, and communicate with those using

Stream Device.

All of these devices, and the Linux boxes running EDM displays, are on a

dedicated private network.

So far, we've had very good success with this. At this time, we have 7 IOC's

running, and more will come online in the near future as we migrate more

subsystems from our old PDP based control system.

Hope this helps...

Dave Reid
University Of Washington Medical Center