Interlocks
The DPS system is supposed to pump down the gas entering through the
XGM. If it fails, the first thing to do is to close the XGM’s dosing
valve, in order to prevent the entire beamline from venting. If the
pressure still rises, we have to switch off the gate valves between
the chambers, but not before the XFEL beam is switched off.
As a last prerequisite, the roughing valve RV1 should be open if we
want to open the gas inlet. This may be closed because we are
evacuating the gas lines, in which case the turbo pumps have no
roughing valves, so we do not want unnecessary gas load.
Pressure interlock
In case of bad pressure, the first thing we want to do is to close the
SCV valve, and to switch off the high voltage HV_LOCK.
The pressures are all a bit lower than they are on the gate valves that
close, so that the gas stops flowing first, maybe then we don’t even
need to close the valves anymore, as the pressure will most likely drop.
We use the gate valves of the DPSs as a proxy for their entire pumping
system: if the turbo pumps behind them are not fine, or the roughing
pressure, they are closed by the interlock system. As they are not
closing immediately, we are not looking at the IsClosed bit, but at
Value, which switches immediately to FALSE should their interlock
trigger.
| Number |
Device Parameter |
Operator |
Limit |
|---|
| c1 |
SCS_BLU_XGM/VALVE/GV3.state.IsClosed |
EQ |
FALSE |
| c2 |
SCS_BLU_DPS-2/VALVE/GV4.state.IsClosed |
EQ |
FALSE |
| c3 |
SCS_BLU_XGM/GAUGE/LV1_PVALVE.Value |
GT |
1e-3 |
| c4 |
SCS_BLU_XGM/VALVE/GV1.state.Value |
EQ |
FALSE |
| c5 |
SCS_BLU_XGM/VALVE/GV2.state.Value |
EQ |
FALSE |
| c6 |
SCS_BLU_DPS-1/GAUGE/PCC5.Value |
GT |
1e-4 |
| c7 |
SCS_BLU_DPS-1/VALVE/GV3.state.Value |
EQ |
FALSE |
| c8 |
SCS_BLU_DPS-1/GAUGE/PCC4.Value |
GT |
1e-6 |
| c9 |
SCS_BLU_DPS-1/VALVE/GV2.state.Value |
EQ |
FALSE |
| c10 |
SCS_BLU_DPS-1/GAUGE/CC3.Value |
GT |
5e-7 |
| c11 |
SCS_BLU_DPS-1/VALVE/GV1.state.Value |
EQ |
FALSE |
| c12 |
SCS_BLU_DPS-2/GAUGE/PCC7.Value |
GT |
1e-4 |
| c13 |
SCS_BLU_DPS-2/VALVE/GV3.state.Value |
EQ |
FALSE |
| c14 |
SCS_BLU_DPS-2/GAUGE/PCC8.Value |
GT |
1e-6 |
| c15 |
SCS_BLU_DPS-2/VALVE/GV2.state.Value |
EQ |
FALSE |
| c16 |
SCS_BLU_DPS-2/GAUGE/CC9.Value |
GT |
5e-8 |
| c17 |
SCS_BLU_DPS-2/VALVE/GV1.state.Value |
EQ |
FALSE |
| c18 |
SCS_BLU_XGM/GAUGE/LV1_PVALVE.AValueSemiRaw |
LT |
1 |
If the needle valve controller is switched off, it gives a perfect
pressure. This is condition c18.
We close the SCV if pressure is too high. Certainly, we don’t care
whether the pressures are bad if the valves to the DPS are closed,
which makes the conditions a bit complicated.
| Number |
Logic |
Action |
|---|
| a1 |
c3 or c4 or c5 or c18
or (c1 and (c6 or c7 or c8 or c9 or c10 or c11))
or (c2 and (c12 and c13 and c14 and c15 and c16 and c17)) |
COff |
And we put the HV inhibit on. This is weird for a safety interlock,
but worst case DOOCS can switch off the HV.
| Number |
Logic |
Action |
|---|
| a1 |
c3 or c4 or c5 or c18
or (c1 and (c6 or c7 or c8 or c9 or c10 or c11))
or (c2 and (c12 and c13 and c14 and c15 and c16 and c17)) |
COn |
SCS_BLU_XGM/VALVE/RV2
The roughing line for evacuation of the gas lines must be closed if
any of the gases are open.
| Number |
Device Parameter |
Operator |
Limit |
|---|
| c1 |
SCS_BLU_XGM/DCTRL/GS_PV_AR.state.Value |
EQ |
TRUE |
| c2 |
SCS_BLU_XGM/DCTRL/GS_PV_KR.state.Value |
EQ |
TRUE |
| c3 |
SCS_BLU_XGM/DCTRL/GS_PV_XE.state.Value |
EQ |
TRUE |
| c4 |
SCS_BLU_XGM/DCTRL/GS_PV_N.state.Value |
EQ |
TRUE |
| Number |
Logic |
Action |
|---|
| a1 |
c1 or c2 or c3 or c4 |
CClose |
The inverse is also true: if the gas evacuation line is open, the gas
lines must be closed. Also, the gas lines should not be opened if the
pressure is high, but they should stay open, so we have an interlock
on itself. Also, it should not be possible to open one gas line if one
of the others is open. The conditions are actually the same, only the
action logic is different.
| No |
Device Parameter |
Op |
Limit |
|---|
| c1 |
SCS_BLU_XGM/VALVE/RV2.state.IsClosed |
EQ |
FALSE |
| c2 |
SCS_BLU_XGM/ASENS/GS_P_OUT.Value |
GT |
-0.98 |
| c3 |
SCS_BLU_XGM/DCTRL/GS_PV_AR.state.Value |
EQ |
TRUE |
| c4 |
SCS_BLU_XGM/DCTRL/GS_PV_KR.state.Value |
EQ |
TRUE |
| c5 |
SCS_BLU_XGM/DCTRL/GS_PV_XE.state.Value |
EQ |
TRUE |
| c6 |
SCS_BLU_XGM/DCTRL/GS_PV_N.state.Value |
EQ |
TRUE |
| No |
Logic |
Action |
|---|
| a1 |
c1 or (c2 and not c3) or c4 or c5 or c6 |
COff |
| No |
Logic |
Action |
|---|
| a1 |
c1 or (c2 and not c4) or c3 or c5 or c6 |
COff |
| No |
Logic |
Action |
|---|
| a1 |
c1 or (c2 and not c5) or c3 or c4 or c6 |
COff |
| No |
Logic |
Action |
|---|
| a1 |
c1 or (c2 and not c6) or c3 or c4 or c5 |
COff |
SCS_BLU_XGM/VALVE/GV1 and /GV2
We want to close the butterfly valve over the turbomolecular pump in
case they or their roughing vacuum goes bad. We do not want to close
them just because the rouging vacuum is closed, because we may simply
be evacuating the gas lines.
| Number |
Device Parameter |
Operator |
Limit |
|---|
| c1 |
SCS_BLU_XGM/TPUMP/TP1.state.RPM80 |
EQ |
FALSE |
| Number |
Device Parameter |
Operator |
Limit |
|---|
| c1 |
SCS_BLU_XGM/TPUMP/TP2.state.RPM80 |
EQ |
FALSE |
As the line merges into one, all other conditions are the same for
both gate valves.
| Number |
Device Parameter |
Operator |
Limit |
|---|
| c2 |
SCS_BLU_XGM/GAUGE/P2_1.Value |
GT |
3e-2 |
| c3 |
SCS_BLU_XGM/VALVE/RV1.state.IsOpen |
EQ |
FALSE |
| c4 |
SCS_BLU_DPS-2/VALVE/SP31_RV2.state.IsOpen |
EQ |
FALSE |
| Number |
Logic |
Action |
|---|
| a1 |
c1 or c2 or c3 or c4 |
CClose |