1. VAC - Ctrl System 04Nov2011

2. Some points to be discussed Give support for the cryogenic control system prepared by Nikhef team for Cryotrap (and Genova for LN2 tanks signals to be integrated in the system). Need to indicate ref. people Status from LAL Some news from EGO (Tango tests...) ‘Actions’ summary

3. Cryotrap ctrl system, the understanding was Cryotrap TRL SYS RACK (Lal team) Usual various vacuum equipment controllers and devices,... Cryogenic device 1 (es LN2 level meter) Cryogenic device 2 (es LN2 level regulator) Cryogenic device...

4. CL1 Level External Tank LN2 External Tank LN2 TL1 Level PID I/O Temperature, T1- T8 Pressure Pc1 Pressure Pc2 CL2 Level A1-A4 alarms Cryostat Vcryo Basis for discussion to be corrected according to the final design and real items

5. Interface between Cryotrap (Nikhef) & LN2 plant (Genova) vs CTRL SYS (LAL) Basis to be corrected according to the final design and real items itemquantitydescription Pc11Pressure of cryostat, 4-20mA, TBC Pc21Pressure of LN2 storage tank, 4-20mA T1-T818 pt100 temp sensors already converted to 4-20mA, TBC Vcryo1 %opening of the refill valve, directly acquired by the valve itself (Normally AI 4-20mA). Note: not the output signal transmitted by the PID regulator but the real valve status, for redundancy. Normally Closed, TBC CL22 Input signal to PID regulator LN2 level inside cryostat (capacitive sensor), retransmitted by PID regulator or directly by its controller (rs232 or better I/O standard), TBC CL1, TL1 4 LN2 level inside cryostat and storage tank (diff pressure sensors), normally AI 4-20mA A1-A44Alarms of LN2 system, DI, relays status to be acquired Spares4Additional DO, relays Spares8Additional AI, 4-20mA or 0-10V Spares8Additional DI, relays Spares1Additional rs232 device TBD TABLE OF SIGNALS from CRYO APP. to general CTRL SYS

6. IdType(*)Goal TriggerActionComments 1A Prevent backstreaming if pump stops and opening a valve in front of a pump OFF P1 OFFClose V22 2A Prevent high pressure in cryotrap tank and in turbo foreline when electrical mains restarts. Critical equipment shall not automatically restart. Mains turns ON after a black out Keep vacuum valves closed and pumps off. The station will be supplied with UPS, dry pump included. Vcryo will also remain closed (NC) 3A Prevent gas backstreaming if pump stops and opening a valve in front of a pump OFF Rotating freq. P21 < thresholdClose V21 4C Prevent to open the valve in front of the turbo if cryotrap is not under vacuum Ge1> 5 mbar AND Ge2> 5 mbar OR Ve1 closed Close V21 5 C TBC Protect large gate valve VNI_cryo between cryotrap and tower (Same for VWI_cryo, VWE_cryo, VWI_cryo) Ge2>5 mbar Forbid VNI_cryo opening (type C and not A, because Large gate valves should not close automatically with this simple interlock, other checks should be added, TBC) 6APrevent to have not the possibility of closing valvesCompressed air low (relay)Close all valves (**)Must be activated before the air is too short 7A Protect the system from overpressures in case of cryostat leak T4 5 mbar AND V1 closed AND V21 closed TBC Close VNI_cryo, LV NE TBC, Vcryo LV NI is not closed, but remains open: LN2 is let evaporating in the 3km tube (200 liters LN2 -> 40 mbar) 8A Prevent the back-diffusion of adsorbed gases in the tubes and on mirrors T4>threshold4 AND T5>threshold5 Close VNI_cryo, LV NI Case of level sensor malfunction or stop of the LN2 refill 9TBC TABLE OF INTERLOCKS, NOT FINAL. Some driven by Cryo signals

7. Actions Finalization of the general document describing the system listing the interlocks, new pumping stations … (Antonio + All) https://workarea.ego-gw.it/ego2/virgo/advanced- virgo/vac/control-system/meeting-03may2011/Vac_CTRLSYS_01may.docx/ Antonio will circulate the updated draft within November Better to fix now next meeting date, Wed14Dec ore 14 ? Please, propose From June : Some tests about racks heating is to be done: LAL team will check what are more critical boards/items, then EGO team will check their temperature variation with thermocamera stopping some fans From June : Ego will prepare a more detailed mechanical design about the proposal of hanging the 'control command rack' to 'seismic' isolate it from the platform. A proto has been prepared, shall be tested within the end of the year (Irene F.) From June: Noise measurements of some selected fans to be completed from Ego