Experimental Physics and
Industrial Control System

"Denison, PN \(Peter\)" <[email protected]> · Mon, 26 Feb 2007 12:45:03 -0000

> From: Mark Rivers [mailto:[email protected]] 
> - Do you know of any other sites that might have already done 
> a 3.14 OSI conversion?  How are new accelerators (Diamond, 
> Australian, Canadian) communicating to PLCs from EPICS?  Are 
> they using MODBUS or some other protocol?

Diamond is using Omron PLCs, communicating via the HostLink protocol
over RS232 serial lines.

We have a StreamDevice protocol file to do the protocol handling, and an
Asyn serial driver. In order to reduce overhead on the communication
path, though, some applications transfer large blocks of data from the
PLC memory, and then use a series of subarray records to extract the
required data from the correct position.

-- 
Peter Denison, Senior Software Engineer
Diamond Light Source Ltd., Diamond House, Chilton, Didcot, Oxon, OX11
0DE
Tel: +44 1235 778511

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System