Vacuum Control System

• AdV architecture similar to the existing one

• one autonomous station per “pumping unit” (about 30 units : tower, tube station, cryopumps …)

• low level hardware interlocks

• other protections (cleanliness for example) at software level

• monitoring and steering of the whole system from a single place

• Some constraints

• reuse existing hardware

• EMC compatibility and other noises (fans, …)

Design issuesThe main problem is the definition of the central unit for control. There is a large amount of I/O (One UHV tower = 65 Digital Inputs, 20 Digital Outputs, 10 RS232 ). Two solutions are possible : PLC and PCI.

• PLC :• standard industrial solution• long-term maintenance OK• reduced amount of software to be written• no EMC problem

• handling of RS232 links• limited intelligence (depends on PLC)

• PCI (similar to the current OS9 solutions ):

• easy handling of various interfaces• large computation power

• more software to be written• EMC• long-term maintenance

New cost estimates• Cabling :

• cost for 1 tower 2 cost for tube station• Total 150 k€

• Computing units (estimations with current IO) :

• PLC : • Crouzet : not enough powerful• Wago : 3 k€/station. But one PLC is able to handle only 5 RS232 links. Need to handle two PLC on a single device. Becomes tricky. Moreover, no profibus for new devices except using other PLC costing 10 times more 15 k€/station• Schneider : 15 k€/station. Luxury PLC because you need to handle 5 RS232 modules. Moreover, each RS232 module which costs 1200 € each• Siemens : 15 k€/station. Similar problem with RS232 : 1 link by module, (550€/module) 10 modules big PLC (3 k€)

• CPU : • National Instruments : 15 k€/station

For the moment, in any case, we reach 400 k€ for the computing units and a total of 550 k€.

New cost estimates

• Reusing existing devices with existing RS232 links is a major constraint on the design and significantly increases the cost. About 100 k€ could be saved if they are removed.

• Moreover, the use of RS232 links prevents to move the crates far away from the towers to avoid disturbances.

• Our conclusion is that the possibility of changing the RS232 interfaces should be carefully investigated by EGO vacuum group before any decision on the control system design.