1. Hilko Spoelstra, Vacuum Group Specialized Technical Services / AD
Vacuum Control System
Hilko Spoelstra, Vacuum Group
Specialized Technical Services / AD
CDR MPSID and MPSVAC

2. Outline Introduction Vacuum Control System Requirements Documents
Vacuum interface to PLC based BIS (MPSVAC)
Next steps
Conclusion

3. ESS Vacuum Group Target
Normal Conducting LINAC
Super Conducting LINAC
The ESS organization charges the ESS Vacuum Group (VG) with the responsibility for all ESS vacuum systems including not only the Accelerator, but also Instruments and Neutron Beam Lines and the Target.
The main task of the ESS VG is to support the in kind contributions on the vacuum system and the integrated vacuum design of the ESS complex.
Neutron Beam lines

4. LINAC Vacuum System
Source
LEBT
RFQ
MEBT
DTL
Spokes
Med. β
High β
HEBT
Terminology: (Vacuum) Section: LEBT, RFQ, MEBT, Spk, etc.
Vacuum Sector: The volume/part between two Sector Gate Valves

5. Vacuum equipment summary for the accelerator
Standardization of vacuum equipment through a Framework Agreement (FA)
Single suppliers for each type of equipment (exception for gauges in the SCL)
Framework agreements even applicable for some of our in-kind partners.
The Gate Valves are the key point for this presentation

6. Vacuum Control System
Complete in-house design for control racks and control logic
Vacuum Group - > Hardware and Electric design (EPLAN)
Integrated Control System Group -> PLC and EPICS IOC programming
Common approach for all vacuum systems: Accelerator, Target and Neutron Instruments
The vacuum control system is complete designed in house by the vacuum group and ICS. Where the Vacuum Group is responsible for the hardware/electrical design, Rack and wiring design in Eplan and the assembly and wiring of the racks.
ICS takes care of the PLC, EPICS IOC programming and Archiving etc.
There will be a common approach for the all ESS Vacuum systems, including the Accelerator, Target and Instruments, using the same design concept and using the standardization for vacuum equipment.
And although there should be a sharp boundary between responsibilities, I think due to good cooperation we have between vacuum and ICS its more like a gray zone in a positive way.
Epics Domain
ICS team responsibility
Vacuum group responsibility

7. Vacuum Control System Overview
IOC
Serial to Ethernet Server
(Moxa Boxes)
Real Time I/O
IPC
Control Rack
PLC
An overview of the vacuum control system
In the bottom we have the vacuum equipment as mounted on the accelerator. Here are the gauges, the different types of pumps, the valves, RGAs etc.
As no electronics is allowed in the tunnel, the controllers are separated from their vacuum devises. They are located in the vacuum control racks with the rest of the control equipment.
We have the PLC for local protection of the vacuum system, acting on interlock signals from gauge and pump controllers. The plc holds all the control functionality for safe operation of the vacuum system and as well the different modes for eg. automated start up, leak check etc. It’s doing it by acting on interlock signals from gauge and pump controllers.
In the middle we have the serial to Ethernet server (or moxa boxes) for communication between the EPICS system and the controllers for reading out the PVs for the control screens, archiving and as well to modify settings or setpoints remotely in the controllers.
And finally we have real time IO for archiving.
More about this later.
Valve Interface
Primary Pump Controller
Turbo Pump Controller
Ion Pump Controller
Fast Gate Valve Controller
Gauge Controller
Mass Flow Controller
Residual Gas Analizer
Tunnel
Network Communication
Digital I/O
Analog Out
Serial Communication

8. Controllers for pumps and gauges
The vacuum controllers themselves are the “brain” of the system. Internal protection circuits are always active.
Programmable threshold/interlock signals within the controllers are used for process control and interlocking.
Analog outputs representing the pressure are used for archiving.
RS232 serial communication is used for visualizing parameters on the OPI, archiving and setting up the vacuum controllers remotely.

9. Vacuum Control, PLCs
Interlock PLC
VBP
Process PLC

10. Vacuum Sector Valves Interlocks Machine Protection & Beam Permit
PLC & Distributed IO:
Allows the centralization of the interlocks signals.
Flexibility on :
- Selection of the Interlock’s trigger.
- “Voting Plan” can be done case by case.
- Valve(s) to be closed in case of interlocks.
- Evolution & Modification.
Reduce cabling work (No Inter-section cabling = No Inter-racks cabling).

11. Vacuum Operation Data Acquisition of Analog values
Critical systems
Gauges on RF Couplers
1 kHz sample frequency
Time stamping to ESS master clock
Real Time AI
The PVs coming from the vacuum controllers will be read out trough the moxa boxes as all of our vacuum controllers have a serial RS232 communication ports. These values can then be used for showing on the OPIs.
For archiving the pressure related PVs, we use 2 different systems.
For less critical system like Pirani gauges on the beam vacuum, pumps, gauges on the the isolation vacuum and gauges on the distributed pumping we use these values read out trough the RS232 port. The sampling frequency is 2-3 Hz and it has no time stamping.
For more critical system like the cold cathode gauges on the RF couplers and the cold cathode gauges in the beam line we will use the analog outputs of the controllers. These values representing the pressure directly proportional as a 0-10V signal with a minimum in time delay. This analog signal is read by a real time data acquisition system from Beckhoff. The signals will be stored in a 15 minute circular buffer and archived in an event of a pressure rise. These signals are time stamped to the ESS Master clock and can therefor easily be used during fault finding to relate to specific events or faults in time. This however is still work in progress
Less critical signals
Read out through RS232
2-3 Hz sample frequency
No Time stamping

12. MPS – Interfaces Requirements
Through multiple workshops and use cases between the MPS group and the Vacuum group, a set of requirements has been created for the interface between the Vacuum Control System and the Machine Protection System.
Concept and Scope for Machine Protection of Vacuum (Valves) (ESS )
Machine Protection Requirements on Vacuum Valves     (ESS )
Machine Protection Requirements on MPSVAC                 (ESS )
Machine Protection Requirements on PBVI  (ESS )
Machine Protection and PBVI Interface Control Document (ESS )
Machine Protection Analysis Document for Vacuum (ESS )
Machine Protection and Vacuum Valves Interface Control Document (ESS )
This was a small introduction to the vacuum control system. I’ll now continue with the interface with MPSVAC.
Through multiple workshops and use cases we had with the MPS group a set of requirements have been created for the interface between vacuum and the machine protection system. They are described in the following CHESS documents:

13. Requirements Main requirements:
PBVI = Proton Beam Vacuum Interlock PLC
VBP = Vacuum Beam Permit
SGV = Sector Gate Valve
MPSVAC = Machine Protection System PLC interfacing with Vacuum
It takes to much time to go through all requirements but the major requirements are pointed out here:

14. Beam Permit
The Linac has a total of 109 vacuum gate valves that can intercept the beam (109 Vacuum Sectors).
One Beam Permit / Vacuum Sector
The Vacuum Interlock PLC activates a Vacuum Beam Permit for a sector only if the Sector Gate Valve for that sector has received the command to open and if the Sector Gate Valve is in the open position (read by both position switches).
Each Vacuum Beam Permit is hard wired to the MPSVAC PLC IO
So this tables shows that vacuum has 109 interceptible devices in the beam of which 105 are normal gate valves and 4 are Fast gate Valves.
For each gate valve we have one Beam Permit.
The vacuum beam permit will only be given when the command has given to open the gate valve and the gate valve is in the open position.
The beam permit is hard wired through a change over relay contact to the MPSVAC system.

15. Gate Valves Gate valves: Are used to separate two vacuum sectors.
Have relatively slow response times (0,9 < t <15 s.) and have therefor an interface with the PLC-based BIS.
Have a pneumatic actuator with 24 Vdc solenoid valve.
Have double pair of positions switches (MPS-REQ-VAC-1)
Through the standardisation and framework agreement ESS uses Series 8, Series 10 and Series 48 gate valves from VAT. (sizes from DN40 – DN250).

16. Fast Valves 4 Fast Valves installed in the LINAC
1 on each extremity of the Super Conducting Linac
1 in the A2T prior to the shield wall
1 in the DmpL
Series from VAT
Due to fast closing times (< 15 ms.) Fast Valves are connected to the FBIS and out of the scope of this CDR.

17. Opening of a Sector Gate Valve
No automatic opening of the gate valves.
Can only opened by an operator if at least one of the input criteria on each side of the gate valves is met. (input criteria is by default the threshold relays from a gauge or pump controller)
OPEN Cmd
There is no automatic opening of the gate valves. All the gate valves in the beam line stay closed until opened by an operator. To open the gate valves the input criteria for that particular gate valve needs to be met. By default this means that the gate valve needs to see an ok signal from at least one predefined pressure sensors (gauges or ion pumps) on each side of the gate valve. When this criteria is met, and the gate valve is in the open position measured by the position switches the Vacuum Interlock PLC automatically enables the Beam Permit for that vacuum sector.
The logic looks like this. so the PREV1 and 2 switches come from the gauges upstream and the NEXT 1 and 2 from downstream the gate valve.
Vacuum Interlock PLC
Beam Permit “1”

18. Automatic closure of a Sector Gate Valve
Automatic closure of the sector gate valves is triggered when both input criteria on at least one side of the gate valve is failing.
For the obvious reasons Gate valves do close automatically. This happens when both the signals on at least one side of the gate valve goes bad. So both sensors on one side needs to see a high pressure before the gate valve closes. With command to close the gate valve, the Vacuum Interlock PLC will disable the Beam Permit as well.. The interlock levels of the gauges and the hysteresis will be set case by case. So there will be a threshold before the gate valve can be opened and it requires a certain pressure increase before the valve will close again.
Vacuum Interlock PLC
Beam Permit “0”

19. Electrical Diagram Gate Valve
This is the electrical diagram of the gate valve.
Down in the bottom we see the wiring of the gate valve with the connection of the solenoid valve for the pneumatic actuator and the double pair position switches. From the gate valve there are two short cables going to a connection box placed in the vicinity of the gate valve. This gives the possibility to connect both the vacuum Interlock PLC and the MPSVAC PLC to the position switches. The connection box has as well the advantage of making possible future fault finding as this gives easy access to measure or manipulate signals. In the top we can see the control signals to and from the vacuum interlock PLC.
Finally I want to point out that the drive power for all the gate valves comes from a different power supply than the read out of the switches. The main reason is that in the event of a power outage we want all valves to be closed but we still want to be able to check the position switches. So parts of the vacuum system like the pumps and the drive power for the valves are on normal power while the PLCs and gauge controllers are on UPS power.

20. Electrical Overview, Beam Permit
MPS-REQ-PBVI-1
MPS-REQ-PBVI-2
MPS-REQ-PBVI-3
MPS-REQ-PBVI-4
The wiring diagram for the Beam Permit. In the top we see the control signals from the position switches of the gate valve and the open command going inside the Interlock PLC who will check this data. If all criteria is met, it will active relay Q8 and change the state of the change over contact going to the MPSVAC. At the same time the Interlock PLC will check the a second contact from that relay to confirm the relay is activated.
Right in the bottom is the MPS Patch Panel which is the direct interface to the MPSVAC system.

21. Failure Modes for Gate Valves
Gate Valve Position
Position Switches Activated
Vacuum Beam Permit
Compressed air loss in open position
Undefined
No switches activated, transition mode
NOK
Compressed air loss in closed position
No change in position
Closed position activated
Compressed air loss during transition
Control power fail in open position
Gate valve closes
Closed posion activated
Control power fail in closed position
Control power fail during transition (either way)
Position switch power fail (transition, open or closed)
To open the gate valve the vacuum interlock PLC supplies 24V through a relay to a solenoid valve. The solenoid valve in its turn supplies the compress air to the pneumatic actuator that drives the gate valve. This table shows what happens if one of the systems would fail. The table shows that in all failure modes where the gate valve closes unintended, the Beam Permit will be removed.

22. Beam Destination and Vacuum Sectors
ESS LINAC has 8 beam destinations.
Vacuum Interlock PLC does not care about the beam destination.
Vacuum Interlock PLC creates an Beam Permit for each vacuum sector which is “OK” if the command is given to open the Sector Gate Valve and if the Sector Gate Valve is in the open-position.
Beam destination logic is handled by the MPSVAC PLC system.
There are 8 Beam destinations along the ESS LINAC. Before beam can start one needs to make sure that all the gate valve upstream of the beam destinations are open while we do not care about the ones downstream the beam destination. The vacuum Interlock PLC does not take care of this functionality…..

23. Next steps…
Necessary control logic has been implemented and commissioned in the Vacuum Interlock PLC for the LEBT section to satisfy the interface requirements. This will be the base for the complete LINAC.
Hardware is installed in the LEBT vacuum control rack to interface with the MPSVAC PLC system to fulfil all requirements.
The integration of the Vacuum Interlock System (Beam Permit) and the MPSVAC systems has to be commissioned for the LEBT.
A procedure for commissioning and periodic tests of the Vacuum Beam Permit and the Gate Valve has been discussed but control functionality has not been implemented yet. The system will be EPICS based.

24. Conclusion
The ESS Vacuum Control System is designed in-house by the Vacuum Group and the Integrated Control System Group.
Through workshops and use cases the MPS group and the Vacuum group have created a set of requirements.
The requirements are addressed by implementing:
Sector gate valves with double position switches and special interface boxes to interface both the Vacuum Interlock System and the MPSVAC PLC System.
Interlock PLC system with logic for the Vacuum Beam Permit.
Hardware installed in the vacuum control racks to interface the Vacuum Beam Permit with the MPSVAC.
Next steps:
Commissioning of the integration of the Vacuum Beam Permit signals and Sector Gate Valve signals to MPSVAC as a base for the complete LINAC.
Integration of a test sequence for periodic test of the Sector Gate Valves and Vacuum Beam Permits.

25. Questions?