Post on 02-Jan-2016
LN2 filling system
1. Filling the buffer tank2. Filling the collector tube3. Filling the detectors4. Venting the collector tube5. Monitoring then go to 1 or 2
1. Filling the buffer tank
• Automatic?• Alarm on the buffer tank to alert operators?
2. Filling the collector tube
• Logic sequence:– Open VP – Open VIN– While FP wait for TP to get to LN2 value– Close VP
3. Filling the detectors
• Logic sequence:– (VIN already open, VP closed)– Open VDi– Wait until TVi is at LN2 temp– Close VDi
4. Venting the collector tube
• Logic sequence:– Close VIN– Open VP
5. Monitoring
• Logic sequence:– Check P,V against alarm threshold ->Step 1: Fill the buffer– Check Tdi against limit value ->Step 2: Fill all the detectors– Check time since last fill ->Step 2: Fill all the detectors
Implementation – collector
VIN
24V
NI 9476
VP
24V
NI 9476
NI 9217 NI 9425
10 – 40 V DC
NI 9217
Collector
SafetyValve(s)
NI 9476 1 + 1/column
NI 9425 1 /column
NI 9217 1 +1
24 V AC 1 +1/column
10-40 VDC 1/column
Implementation - detector
VDi
24V
NI 9476
NI 9217
Collector
SafetyValve(s)
NI 9476 1/detector
NI 9217 1
24 V AC 1 /detector
Dewar TDi
Implementation – monitoring
V
Collector
P
NI 9217NI 9425?
NI 9217NI 9425?
Dewar
Crystal
NI 9
217
NI 9
217
Custom modules
To NI 9217
To NI 9217
PTi From N
I 9476
12 V
Power On/Off
Open / Close
Opened / Closed
Powered Y/N
To NI 9425
Read PT100 Distribute valve signal Command one valve
10-40 V DC
Read flux sensors
M1 M2 M3 M4
12V
M3 working principle
12 V
Power On/Off
Open / Close
Opened / Closed
Powered Y/N
M3
12V
NI 9476
Valve
12 V
Connection diagramCompact Rio Crate (6 x NI 9217, 1 x NI 9476, 1 x NI 9425)
PT100
PT100
Prox
M1
12V
Prox
M2 M3
Valve
12V?
12V?
M4