1. Electrical and Controls
Chris Scanlon
LCLS-II 2K Cold Box FDR
March 9, 2017

2. Outline Electrical Overview Cold Compressors Controls Overview Alarms
Control Loops
Cold Box Trips
Interlocks
Sequences
Documentation
LCLS-II 2 K CBX FDR, Mar 9, 2017

3. Overview
LCLS-II 2 K CBX FDR, Mar 9, 2017

4. 6 x 35A 480V ac 3 phase circuits for cold compressors
Electrical Overview
6 x 35A 480V ac 3 phase circuits for cold compressors
2 x 20A 120V ac single phase circuits for control box
One from house power
One from emergency power (UPS and generator backup)
Routed in conduit
Motor and bearing cables routed in cable tray
Control cabinets to be located within 10m from motors to accommodate maximum cable length
LCLS-II 2 K CBX FDR, Mar 9, 2017

5. Six differently sized centrifugal cold compressors Two motor sizes
One high speed, one low speed
Six identical cold compressor control cabinets
Each contains an identical combination magnetic bearing controller and motor drive (Mecos MMC15)
Hardwired stop and fault signals
CANopen communications for speed command/readback, faults, warnings, etc
Designed with seismic bracing
LCLS-II 2 K CBX FDR, Mar 9, 2017

6. Cold Compressor CAN Signals
Name
Can Addr
Access
Datatype
Description
Unit
Speed SP
2000h
R/W
int16
Speed Setpoint. Cannot be beyond max speed Hz
Current Speed
2001h R
Current Speed of motor
Run/Stop
2009h
bit
1 to Start, 0 to Stop the drive
Drive Enable
200Bh
Set bit 1 to enable the dive control via CAN Bus
Floating
200Ch
Bit is set to 1 by the firmware if the system is floating
System Status:
Initializing
2025h
Indicates that the system is starting up and initializing (1) or ready (0)
Motor Temp
2003h
Temperature of the motor; Limit: 200 internal units for all motors except No.1 where its 150 units. Sensor is PTC
Internal Units (IU)
Mains Hours
3004h
int32
Indicates the number of hours the system was switched on
Hrs
Floating Hours
3005h
Indicates the number of hours the system was floating
Rotating Hours
3006h
Indicates the number of hours the system was rotating
Approx. Set Point Force Z Bearing
2405h
Approx. SP force to the axial bearing in internal units
Divide by #12 to get a relative value of the bearing load IU
Approx. SP Force Z Bearing Trip Limit
240Bh
If the Sp force (#11) of the axial bearing is beyond this limit an error occurs and the system gets tripped. 900N~4095 Internal units
Approx. Set point Force Z Bearing Maximal Value
2425h
Max SP force (abs value) of the axial bearing. This value measures the peak. After reading this value, you have to overwrite this value with a ‘0’ to reset actual peak value(drag indicator). Divide #12 for relative value of bearing load
Unbalanced Values
A Bearing
2026h
32 bit Array
Square of the unbalanced value on the A bearing.
If this value is beyond the limit (#20^2) an error occurs
B Bearing
Square of the unbalanced value on the B bearing.
If this value is beyond the limit (#21^2) an error occurs
Reset Faults
200Eh W
Set bit to 1 to clear fault
Error Status
2020h
16 bit Array
Errors and warnings, see also sheet Error list
SlfChkFlt
2021h
Self Check Faults, see also sheet Error list
Sys Status Rotating
3FFFh
Bit 1 of 16 Bit Array (from Bit0-15)(Bit 0 = Floating, Bit 1 = Rotating)
Unbalanced / Orbit limit value Bearing A
2027h
Unbalanced Value limit on the A bearing
Unbalanced / Orbit limit value Bearing B
Unbalanced Value limit on the B bearing
LCLS-II 2 K CBX FDR, Mar 9, 2017

7. PLC controlled system Variables shared with other systems
Controls Overview
PLC controlled system
Dedicated Allen Bradley L81 processor
Same processor manufacturer/generation as CDS/CMs
Ethernet communications to temperature diode transmitters, EPICS and other PLC systems
CANopen to Ethernet gateway for cold compressors
Variables shared with other systems
CM heater request
CM JT PID LL set point
DB HX bypass valve
DB linac supply valve
LCLS-II 2 K CBX FDR, Mar 9, 2017

8. Local HMI for local, manual operation I/O count
Controls Overview
Local HMI for local, manual operation
I/O count
35 digital inputs, 29 spares
23 digital outputs, 9 spares
19 analog inputs, 13 spares
8 analog outputs, 8 spares
13 temperature diodes, redundant pairs, 7 spare inputs
High accuracy (0.04%) pressure transducers
Better evaluation of cold compressor efficiency
LCLS-II 2 K CBX FDR, Mar 9, 2017

9. Return pressure from linac Return temperature from linac
Alarms
Flow to 4K cold box
Return pressure from linac
Return temperature from linac
Fifth CC outlet pressure
Fifth CC outlet temperature
Insulating vacuum
Flow surge
From cold compressors
Power supply failure
PLC card failure
LCLS-II 2 K CBX FDR, Mar 9, 2017

10. 2 active during pump down and 2K operation
Control Loops
8 control loops
2 active during pump down and 2K operation
Fourth cold compressor speed control based on flow
Fifth cold compressor speed control based on inlet pressure
LCLS-II 2 K CBX FDR, Mar 9, 2017

11. Cold Box Trips 18 trip points 3 surge trips CANbus failure
Flow is 5% less than set point
Flow rate change is too high
Pressure spike at linac
CANbus failure
Process Variable
Trip Level
Effect
PT 41160H
> 2 atm
2K cold box trips
PT 41150H
FD41100
FB41100
PV41160R
< 95%
PV41170R
LCLS-II 2 K CBX FDR, Mar 9, 2017

12. Interlocks Interlocks Opening outlet valves Starting cold compressors
Magnetic bearings levitating without faults
Pressure difference on both sides of valves < 0.06 atm
Instrument air pressure to valves
Starting cold compressors
Mag bearings levitating without faults
Inlet pressure > 1.05 atm
Outlet valves open
Surge alarm cleared
LCLS-II 2 K CBX FDR, Mar 9, 2017

13. Sequences Backfill sequence Pump down sequence
Backfill valve controls so 4K cold box LP pressure doesn’t drop below 1.08
Valve closes when linac reaches 1.1 atm
Pump down sequence
Preparation
Open outlet valves
Start cold compressors, set gear ratios, fifth CC PID set point, fourth CC min and max
Open CM JTs for 120 seconds to cool down
Pump down
Steps governed by 2K cold box inlet pressure
Command JT PID liquid level set point
Set flow set point of fourth CC PID
Send DB HX bypass valve position to increase density of CC gas
Control DB linac supply valve based on line A pressure into DB
Request heat from CM heaters
Transition to steady state
After inlet pressure is atm, set flow of fourth CC PID to 200 g/s
Ramp gear ratios of first to third CCs to steady state value
LCLS-II 2 K CBX FDR, Mar 9, 2017

14. Cold Box Trip Sequence Outlet valves close
Prevent reverse flow of gas
Minimize linac pressure
Reduce forces on cold compressors
Cold compressors commanded to stop
Linac liquid level commanded to 75%
Closes JT valves
Maintain minimum linac pressure
LCLS-II 2 K CBX FDR, Mar 9, 2017

15. Documentation Document No. Title Author Status 79222-1000 to 1012
LCLS-II 2K Cold Box Control System Drawings
T. McCool
Jlab review
LCLS-II Cryogenics Building Electrical Distribution JLab Scope
A. De Lira
Released
LCLS-II-4.8-EN-0768
Cryogenics Plant 2K Cold Box Software Specification
C. Scanlon
JLab review
79222-C7001
LCLS-II 2K Cold Box System-Instrument List
LCLS-II 2 K CBX FDR, Mar 9, 2017

16. Summary Electrical design is mature and released
Controls hardware and software design
Alarms, trips, interlocks, control loops are the same as JLab and FRIB
Incorporate JLab’s 20+ years of experience
Cold compressor magnetic bearings experience no wear during normal operation
Software minimizes upsets to cold compressor train
LCLS-II 2 K CBX FDR, Mar 9, 2017