1. Alexei.Kuryakin@cern.ch 27/10/2009 1 PHOS Cooling status (1-27 Oct) Brief History: 28 Sep start cool down. Steps (by liquid) was: +17, +5, -3, -10, -15, -20, -25, -30, -29.5°C. 2 interlocks happened and was fixed: – 1 Oct – alarm on ECV controller battery fail, fixed; – 19 Oct – alarm on low pump cover temperature threshold, fixed. At the moment (27 Oct): Nominal PHOS stabilization temperature achieved. Temperature (by Pt100 sensors): Cooling liquid (C 6 F 14 ): -29.50 ± 0.06°C PWO2: -25.00°C,PWO3: -24.40°C,PWO4: -25.02°C FEE2: +15.41°C,FEE3: +16.31°C,FEE4: +10.16°C. Humidity (by 3×PWO + 2×FEE sensors): PWO2: 42,46,23%,PWO3: 43,43,29%,PWO4: 64,38,26% FEE2: 7,4%,FEE3: 12,16%,FEE4: 7,8% Liquid level in receiver tank ~53 Liters.

2. Alexei.Kuryakin@cern.ch 27/10/2009 2 PHOS Cooling status (1-27 Oct) PHOS temperatures (overview) Nominal stabilization temperature achieved 21 Oct cooling liquid (C 6 F 14 ) FEE2FEE3 FEE4 PWO2 PWO3PWO4 Interlock 1 Oct. Interlock 19 Oct.

3. Alexei.Kuryakin@cern.ch 27/10/2009 3 PHOS Cooling status (1-27 Oct) PHOS temperatures (details) In constant FEE state ± 0.1°C PWO stability shown cooling liquid (C 6 F 14 ) PWO2 PWO3 PWO4 Stability of cooling liquid average (per control cycle) temperature are: -29.50 ± 0.06°C FEE switch on/off cause temperature variations PWO3 temperature 0.5°C higher then PWO2,PWO4 (why?) Temperature difference between PWO and cooling liquid is about 4.5°C

4. Alexei.Kuryakin@cern.ch 27/10/2009 4 PHOS Cooling status (1-27 Oct) Cooling liquid level ~53 L Temperature effect + (possible) leak ~1 L/week (?) +5 ° C -3 ° C -25 ° C -10 ° C -30 ° C -20 ° C -15 ° C Interlock 19 Oct by pump cover temperature Interlock 1 Oct by ECV controller battery, +25°C -5 ° C ~3 Litres of C 6 F 14 filled 21 Oct Now ~53.3 Litres Need more time to eastimate leak

5. Alexei.Kuryakin@cern.ch 27/10/2009 5 PHOS Cooling status (1-27 Oct) PHOS-2 humidity FEE2 PWO2

6. Alexei.Kuryakin@cern.ch 27/10/2009 6 PHOS Cooling status (1-27 Oct) PHOS-3 humidity FEE3 PWO3

7. Alexei.Kuryakin@cern.ch 27/10/2009 7 PHOS Cooling status (1-27 Oct) PHOS-4 humidity FEE4 PWO4

8. Alexei.Kuryakin@cern.ch 27/10/2009 8 PHOS Cooling status (1-27 Oct) Pump cover temperatures Pump2 Pump1 Pumps works in round-robin order (8 hours per cycle) to equalize working times

9. Alexei.Kuryakin@cern.ch 27/10/2009 9 PHOS Cooling status (1-27 Oct) Compressor cover temperatures Comp.2 Compressors also works in round- robin order (8 hours per cycle) to equalize working times Comp.3 Comp.4 Comp.1

10. Alexei.Kuryakin@cern.ch 27/10/2009 10 PHOS Cooling System status (1-27 Oct) Concept scheme (just to remind) Evaporator (suction header) Condenser (discharge header) 4 Compressors Freon R404A receiver Water condenser for freon cooling Heat Exchanger R404A   C 6 F 14 Electric Control Valve ECV controller 2 Pumps Receiver tank 65L C 6 F 14 Cooling server alidcscom252 LAN2 DCS server alidcscom072 phs_top project PVSS LAN1 DIM 4 compressors, 2 pumps, 3 heaters, 2 valves, Electric Control Valve + controller, fan, 3 pressure + 14 temperature sensors, liquid level sensor, thermo/oil/pressure relays, funless industrial computer, 10×I-7000 RS-485 remote data acquisition modules, 6×ELMB cards, 15 humidity + 96 temperature sensors in PWO,FEE PHOS Control unit (ADC, DIO etc) RS-485 Feedback temperature sensor

11. Alexei.Kuryakin@cern.ch 27/10/2009 11 PHOS Cooling System status (1-27 Oct) PHOS DCS servers scheme PHOS cooling control - alidcscom252 (AliPhosCool program) PHOS cooling client - alidcscom074 (PVSS, phs_col project) PHOS cooling top GUI – alidcscom072 (PVSS, phs_top project)

12. Alexei.Kuryakin@cern.ch 27/10/2009 12 PHOS Cooling System status (1-27 Oct) Cooling control server: alidcscom252 Cooling plant works as DIM server under control of AliPhosCool program designed in VNIIEF,Sarov. RS-485 and CAN devices uses for data taking & control. Cooling server alidcscom252 Special funless industrial computer, located inside cooling plant

13. Alexei.Kuryakin@cern.ch 27/10/2009 13 PHOS Cooling System status (1-27 Oct) Cooling top GUI server: alidcscom072 Cooling plant GUI works as DIM client under PVSS. It ’ s fully integrated into ALICE DCS structures. But (at the moment) shifter can only view cooling data. To control cooling, expert should login to alidcscom252.

14. Alexei.Kuryakin@cern.ch 27/10/2009 14 PHOS Cooling System status (1-27 Oct) Stabilization algorithm PHOS cooling stabilization algorithm based on compressor switch on/off by feedback temperature sensor. So liquid temperature is not constant, but average temperature per control cycle is stable (±0.1°C).

15. Alexei.Kuryakin@cern.ch 27/10/2009 15 PHOS Cooling status (1-27 Oct) Stabilization: control parameters Control parameters: Tstab – wanted stabilization temperature of cooling liquid Delta – temperature corridor to switch compressors on/off NbMin – minimal number of compressors (when T < Tstab-Delta) NbMax – maximal number of compressors (when T > Tstab+Delta) Monitor parameters: Taver – achieved average (per control cycle) temperature of liquid Caver – achieved period (in minutes) of control cycle Naver – achieved average (per control cycle) number of compressors Tstab °C Delta °C NbMinNbMax Taver °C Caver minutes Naver +17101 17.18 ± 0.133.09 ± 1.190.31 ± 0.08 +5101 5.01 ± 0.016.11 ± 0.050.45 ± 0.02 +3101 2.99 ± 0.016.25 ± 0.040.51 ± 0.02 -31.502 -2.94 ± 0.176.71 ± 1.500.79 ± 0.06 -41.502 -3.97 ± 0.037.10 ± 0.190.82 ± 0.04 -10102 -9.99 ± 0.032.24 ± 0.111.16 ± 0.04 -15113-14.94 ± 0.197.44 ± 5.651.69 ± 0.24 -20113-20.31 ± 0.025.32 ± 0.302.55 ± 0.02 -25124-25.21 ± 0.094.81 ± 0.823.43 ± 0.12 -29.50.334-29.50 ± 0.064.64 ± 2.743.74 ± 0.13 -300.234-29.97 ± 0.056.43 ± 3.533.85 ± 0.09 Main control parameter is Tstab. Delta, NbMin, NbMax depends on Tstab. Parameters chosen to achieve stable periodic control cycle (when possible). Large Caver “sigma” means control cycle instability (large variations of period)  Table shows used  parameter values

16. Alexei.Kuryakin@cern.ch 27/10/2009 16 PHOS Cooling status (1-27 Oct) Stabilization: power problem As shown in table and picture, at -30°C we are working near maximum of compressor’s power (~94% of max. power). This cause some instability of control cycle (see pic.). Remind that we have another (more powerful) cooling machine in b.167. At the moment this machine is not ready for operation, so we should plan this item for the next year. Control cycle period is not stable enough

17. Alexei.Kuryakin@cern.ch 27/10/2009 17 PHOS Cooling System status (1-27 Oct) Safety: Alarms and Interlocks PHOS cooling plant have 3 outcome Interlocks: 1.Hardware (normal opened relay) – signal in case of cooling system power off or control computer hang 2.Software (DIM service) – signal in case of alarms, i.e. dangerous conditions (some parameter out of threshold) 3.Network (DIM service) – shows that cooling server (alidcscom252) still alive Software alarm produce interlocks by 35 conditions. Interlock mean that cooling plant halted because it could not continue safe operation. Important note: Cooling system alarms protect cooling plant against damage, but not PHOS PWO & FEE. PHOS protection is job for higher DCS level (PVSS, phs_top project).

18. Alexei.Kuryakin@cern.ch 27/10/2009 18 PHOS Cooling System status (1-27 Oct) Safety: Alarms and Interlocks Software alarms : 35 conditions Each alarm condition have: 1) Flag (enable/disable) 2) Timeout (milliseconds) 3) Threshold (optional parameter) Positive timeout produce temporary device blocking Negative timeout produce Interlock, i.e. fatal alarm and system HALT Interlock require shifter’s command to Reset

19. Alexei.Kuryakin@cern.ch 27/10/2009 19 PHOS Cooling System status (1-27 Oct) Problems and discussions 1.Leak ~1 L per week in PHOS-4, ~8 month of work (without liquid filling). More liquid should be purchased next year (~60 liters ?). 2.Cooling system ’ s Control Parameters and Alarms tuning should be done after period of test operation (partly done). 3.It ’ s not quit clear how L3 magnetic field influent to temperature sensors in PWO. Should be tested. 4.Phs_top (PVSS) actions on cooling plant interlocks is still under discussion and should be modified (maybe). 5.Detail documentation (manuals) should be written for “ cooling experts ”. 6.For next year new cooling machine (more powerful) should be assembled and connected.