VAC - Ctrl System

04Nov2011

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

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 ...

CL1 Level

ExternalTankLN2

TL1 Level

PIDI/O

Temperature, T1- T8 Pressure Pc1

Pressure Pc2

CL2 Level

A1-A4alarms

Cryostat

Vcryo

Basis for discussion to be corrected according to the final design and real items

Interface between Cryotrap (Nikhef) & LN2 plant (Genova) vs CTRL SYS (LAL)

Basis to be corrected according to the final design and real items

item quantity description Pc1 1 Pressure of cryostat, 4-20mA, TBC Pc2 1 Pressure of LN2 storage tank, 4-20mA T1-T8 1 8 pt100 temp sensors already converted to 4-20mA, TBC

Vcryo 1 %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

CL2 2 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-A4 4 Alarms of LN2 system, DI, relays status to be acquired

Spares 4 Additional DO, relays Spares 8 Additional AI, 4-20mA or 0-10V Spares 8 Additional DI, relays Spares 1 Additional rs232 device TBD

TABLE OF SIGNALS from CRYO APP. to general CTRL SYS

Id Type(*) Goal Trigger Action Comments

1 A Prevent backstreaming if pump stops and opening a valve in front of a pump OFF

P1 OFF Close V22

2 A 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)

3 A Prevent gas backstreaming if pump stops and opening a valve in front of a pump OFF

Rotating freq. P21 < threshold Close V21

4 C 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 CTBC

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)

6 A Prevent to have not the possibility of closing valves Compressed air low (relay) Close all valves (**) Must be activated before the air is too short

7 A Protect the system from overpressures in case of cryostat leak T4<90K AND T5<90K AND Ge1>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)

8 A 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

9 TBC

TABLE OF INTERLOCKS, NOT FINAL. Some driven by Cryo signals

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