Friday, August 12, 2011

Hardware implementation of PLC EPICS IOC

The system control for the facility of test contains of one EPICS IOC (input/output controller), by a crate of VME with a CPU of Motorola MVME162. This IOC manages three sub-systems, which are executed with different hardware of I/O:
• Services, ion source, and system of vacuum
• Optics of beam
• Diagnostics of beam

System of Vacuum
The system of vacuum and the services are managed by a PLC system of commercial in order to supply high up-time and use the ladder logic programming benefits. The source of ion was comprised with this subsystem due to the requirements of interlock and considerations of cost. They selected the new PLC line of Quantum from Modicon with a 160 CPU model which is VME based and enabled simple integration with EPICS. EPICS works in a supervisory function only for this sub-system.

Optics of Beam
The PLC advance could also have been applied to control the system of beam optics from a technical point of view, but this will not have been competitive in cost for ISAC where some hundred magnetic and electrostatic power gives must be controlled. They built intelligent controller modules of power supply, which are associated directly to the control connectors of power supplies’ remote. These controllers correspond with EPICS via CAN-bus, with an industry pack of TIP810 on the MVME162. With this analogue signals of approach are digitized right at their documentation and sources and cabling costs are significantly decreased. The controller design of power supply is discussed in a separate input to this conference.

Diagnostics of Beam
The sub-system of beam diagnostic was realized in CAMAC. This assessment was driven by cost and time considerations as TRIUMF has a great base of accessible modules of CAMAC. Some elements of diagnostic, for example the TRIUMF admittance rigs were only obtainable enclosed in CAMAC. For the facility of ISAC, this sub-system will be transferred into VME to let for tight incorporation with the front-end CPUs.

The implementation of software
The software attempt for generating this control system cut down as below:
• Using the tools of EPICS to construct the function block of IOC data base, screens of operator interface, etc. This element did not engage any development of conventional code.
• C code writing
• To incorporating the system of Modicon PLC into EPICS
• For the controller of CAN-bus embedded program
• To adjust the system of EPICS CAMAC for TRIUMF
• For unique tools
• The PLC programming in ladder logic.


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