Early on the Diamond project it was recognized that a number of technical subsystems would be procured as turn key solution from industry. They should supplied complete with control system for effective integration of these. Ideally the control system would comply with Diamond standard to enable future in house support and maintenance. In considering possible turn key systems, RF amplifier, Linac, Cryogenic systems, IDs, beamline components had been supplied to other projects with PLC controls using Siemens S7 PLC’s. In the European market Siemens have between 30 – 40% of the PLC market and is well supported. The high end PLC was set as the S7 PLC.
The Siemens S7 PLC EPICS integration into control system was development using Ethernet and Siemens application level protocol. EPICS support for this had already been developed at SLS and this formed the basis for integration. This provides a facility for single and block register write and read for all of the EPICS standing record types.
The initial assessment proved to be remarkably accurate. Diamond procured a 100 MeV Linac, three superconducting cavities and a cryogenic refrigeration plant all with Siemens PLC control. The Linac used as S7 CPU314 and mix motion control, analogue and digital I/O module and was supplied complete with EPICS integration.
Each of the RF cavities were supplied with three PLC S7 comprising of two CPU314 and a CPU315 and a mix of digital and analogue I/O module complete with an interconnecting Profibus local network. These were integrated onto the EPICS system control by the in house team.
The cryogenic plant was supplied with a mix of digital and analogue I/O and an S7 CPU314. Remote I/O was linked using Profibus a commercial supervisory control and data acquisition system called PCView was utilized for control and overview. This is being integrated into the EPICS control system now.