Status of Interlock Box

1
Status of Interlock Box

• New Interlock Box NTC -I Box
• relative changes in resistor values 4 (NTC)
  instead of 0.4 (Platin)
• simplifies the circuit
• larger value of resistor allows 2 wire
  measurement
• (charge pump in the circuit not necessary any
  more, saves ca. 9 SFR)
• common thresholds for all channels
• no optocouplers
• 16 channels on one board (before 8 on 2)
• shooting temperatures Thigh 0.9º
  C (0.1º C signal is reset)
• 
  Tlow - 18.2º C (-16.9º C signal is reset)

2
Status of Interlock Box
theoretical max. error of the I-Box circuit /-
0.2º C test measurements for 32 channels with
potentiometer, 60 m cable connected to input
all channels inside
theoretical limits
what does it cost? Prototype 8.5 SFR /
channel without costs for mounting
of components, but very expensive
distributor for electrical components
(small
samples with fast delivery) compared to old
I-Box prototype 40 SFR
production 25
SFR estimated new production costs 5.5 SFR
3
Status of Interlock Box

• NTC Resistors
• wanted
• value 10 k?
• size SMD 0603
• tolerances 1 _at_ 25º C and 1 for B-value
• 30 companies contacted
• Semitec (Ishizuka, Japan) 0.9 SFR
• TBPS (Taiyo Juden, Japan) 0.3 SFR
  per 4000 pieces
• irradiation tests in August (thank you to Jens)
  3x10 14 p/cm2
• not accessible till now
• B-value requires further investigation
• for example Semitec resistor _at_ - 6º C max.
  deviation 0.5º C

4
Status of Interlock Box

• TIS
• fail save?
• logic okay 1 error 0
• short and long circuit in lines between
• temperature sensor and
  I-Box
• I-Box and the detector
  power supply
• missing one or several power supply lines (of
  I-Box)
• add additional line to control the 5V and
  its return
• remote test possibility

5
Status of Interlock Box

• Combination with Local Monitor Box
• actual input impedance 800 k?
• request to B. Hallgren for a higher input
  impedance
• next steps
• systematic measurements with NTC resistors
• reliability, tolerance limits, irradiation
• irradiation of I-Box
• study complete system (I-Box, NTC resistor and
  long cable)