vacuum control sysytem for superkekb2 ... control system of superkekb • consolidation of ioc and...
TRANSCRIPT
Vacuum Control System for SuperKEKB
S.Terui, H. Hisamatsu,T. Ishibashi, T. T. Nakamura
J. Odagiri, Y. Suetsugu (KEK), N. Yoshifuji (EJT)
April 2014 OLAV IV
Contents
• Overview of SuperKEKB vacuum control • Upgrade of configuration• Interlock system• High speed data acquisition of CCGs’ pressure values• Conclusions
April 2014 OLAV IV
Overview of SuperKEKB Vacuum Control System
Components AI AO DI DOVacuum Switch 67Gate Valve 501 167Stopper 16 10CCG 605 605 605Ion Pump 605 677 240NEG Power Supply 488 40 200 400
Flow Meter〜
1000 24Temperature Sensor
〜4000 48
April 2014 OLAV IV
SuperKEKB is a two‐ring electron‐positron collider withasymmetric energies
Needs for Upgrading Control System• Vacuum Control System of KEKB had been operated
successfully based on:– VME‐based IOC – CAMAC (scanning ADC and DI/DO)
• SuperKEKB is expected to be in operation for decades from 2014– Availability of CAMAC modules will be a serious issue
• We decided to apply Embedded EPICS concept to upgrading the system with up‐to‐date controllers and data loggers
April 2014 OLAV IV
Upgrade of Configuration• We chose F3RP61 (made by YOKOGAWA) as IOC
– Can work with ordinary PLC’s CPU side‐by‐side on the same PLC‐bus– Can run LINUX
• We chose CompactRIO (cRIO, made by NI)– Can run Channel Access (EPICS protocol)‐Server on cRIO– High analogue I/O channel density in compact chassis (32ch/module) – Can execute high speed data acquisition on built‐in FPGA
April 2014 OLAV IV
OPI
IOC (VME)
CAMAC
PLCDIDO
DO
AI
DI
Channel Access
Ladder Program makes the final decision in ON/OFF control
CPU
GPIB
OPI
cRIOPLC
DIDO
AI
DI
Channel Access
Channel Access
IOC (F3RP61)
CPU
Old System Configuration New System Configuration
The new system is simpler than the old system.
IOC and Data Logger Upgrade
April 2014 OLAV IV
IOC (VME ) IOC (F3RP61)
Before After
CAMAC (very heavy) cRIO (very light)
Concept of Interlock
• We built the normally closed interlock logic with digital input or output modules and the sequence CPU module of the PLC unit to ensure the safety in the operation of the vacuum start‐up and the steady state after it.
• The source components of the input signal are temperature sensors, flow meters, gate valves and beam stoppers, vacuum switch, CCGs.
April 2014 OLAV IV
Interlock Logic (Introduction)• We put a CCG and ion pump every 10 m in SuperKEKB main
ring.• Gate valves divide the vacuum region to ensure serviceability
of the vacuum components.• At least one vacuum switch is installed in the region between
two gate valves.
April 2014 OLAV IV
Vacuum switch
Gate valve
Ion Pump
VSWs detect pressures higher than 1 Pa.
Interlock Logic (CCG)
April 2014 OLAV IV
TIMER T00201 60 sec. HV on/off request
E00201
X00301
vacuum switch status HV on/off request
E00201
discharge status
X00317
delayed timer status
T00201
Y00601
HV output
(close after 60 sec.)
00001
00002
The CCG usually emits gases at the beginning of discharge. The interlock logic has a delay time of 60 seconds.
The relay of vacuum switch status is closed when the pressure is less than about 1 Pa.
CCG
Meaning in Ladder sequence program E: shared relay, I: internal relay, X: digital input relay, Y: digital output relay, L: FA Link relay, U: UNIWIRE relay, T: delayed timer relay
Schematic diagram of ladder program
The CCG controller returns normal discharge status when the pressure is less than about 10‐3 Pa.
Interlock Logic (Steady state, Gate valves)
April 2014 OLAV IV
In the steady state, where some of CCGs in the region operate stably, it becomes possible to apply HV to ion pumps and to activate NEG pumps.
open request
E04001 I00301
steady state
00020 close request
E04101 L00002
steady state next door
Y00803
open
steady state
Gate valve
Without any request to open, the valve remain in close position.
Interlock Logic( Ion pump and NEG activation)
April 2014 OLAV IV
I00301
steady state
00021
Y00813
ion pump HV ready
U00001
NEG activation ready
I00301
steady state
X00529
magnets state
HER only
00022
X00301
vacuum switch status
E00501
interlock kill request
X00301
vacuum switch status
E00601
interlock kill request
E00701
restrict output request
NEG
Ion Pump
When the pressure in the region gets worse in cases, the HV of CCGs is turned off at first.Then the status is no longer a steady state, and the HV of ion pumps and the heater power for NEG activation are turned off immediately by the interlock logic.
These relays kill the request to stop the IP baking and the NEG activation process irrespective of CCGs status.
This relay inhibits the output from power supplies for NEG activation.It will be used for the case where the beam pipe is exposed to air for maintenance, for example.
A procedure of the vacuum start‐up
April 2014 OLAV IV
Start rough pumping with a turbo‐molecular pump (0.26 m3/s for N2) and a scroll‐type dry
pump (0.2 m3/min)
HV is applied to CCGs and ion pumps in the region
TMP
Scroll
Start baking of IPs for 1‐2 days
Activate NEG pumps with a pattern operation for 0.5‐2 days
Check the vacuum switch status
Target pressure is less than 1E‐7 Pa after the NEG activation
Typical trend of pressures in a region between two gate valves after IP baking
and NEG activation
April 2014 OLAV IV
Baking of IP start
NEG activation start
NEG activation end
The test result was good
This point shows the pressure values is less than 1E‐7 Pa.
High speed data acquisition of CCGs’ pressure values
April 2014 OLAV IV
The pressures are usually recorded every several seconds by CCGs located every 10 m in the ring.In an accidental case, therefore, it is sometimes difficult to localize the leak pointwhere the pressure must have risen at first.
High speed recording of pressures for at least several minutes before the accident will help the identification of problem.
Assuming that the propagation speed of pressure rise is same to that of sound (~350 m/s),the frequency of data acquisition of 35 Hz or more is required for every CCG.
Problem
Concept of solution
Request from solution
We chose 100 Hz scanning!
What’s each cRIO doing
Role‐sharing of high speed data acquisition
cRIO
AI(CCGs’ pressure value)
FPGA:Scanning cycle of 10 ms
Real Time(RT) OS :Make from accumulated data with the time stamp to the array of circular buffer.
WindowsPC:Monitoring event triggers. Analyzing pressure data from memory of cRIOs.
Ethernet
D1 D2
D4
D3
D5
D6
D12
D11
D10
D7D8
D9
KEKBMainRing
cRIOs synchronize with a NTP server
CPUThere are twelve cRIO in KEKB.These cRIO connect to the control network.
Flow of the high speed data acquisition
(1) The data acquired every twenty minutes are stored in the memory of the cRIOas the circular buffering system until the trigger is generated.
(2)If the first signal of the pressure rise is excited as the trigger at some stations, the signal is provided to other stations.
(3)After the trigger is generated, the data of the pressure, with time stamp for 5 minutes before entering the trigger and for 15 minutes after entering the trigger, is created on the each cRIO as text file.
(4)The signal as the trigger is monitored by the alarm system. When the operator notice exciting the signal, the operator can get the data from the cRIO.
The test at 2 stations is on the way. It is difficult to establish both RT, which runs CA‐Server, and FPGA.
Conclusions
• PLC‐based IOC was applied to upgrading the vacuum control system of SuperKEKB
• Consolidation of IOC and PLC considerably simplified the configuration of front‐end control
• The test of the control system has been succeeded according to the normally closed interlock logic.
• High speed data acquisition of CCGs’ pressure values is built and under test now.
April 2014 OLAV IV
Thank you for your attention
April 2014 OLAV IV