1. Commissioning of cryogenic crates using Mobile Test Bench 1. The Mobile Test Bench 2. Cryogenics crates and equipment – types of transducers and actuators 3. Electrical tests - instrument, cable & card tests 2. Test and calibration systems for pressure sensors 1. Low pressure bench 2. High pressure bench

The Mobile Test Bench (MTB) was a custom Automatic Test Equipment system, designed for operation in the LHC tunnel. Its purpose was to perform the final test of the cryogenic FIP crates and their attached sensors and actuators.

Mobile Test Bench based on PXI MTB test cables Tunnel cables Connectors panel MATRIX for signals routing DMM1 DMM2 Current generator Resistance simulator CPU FIP BUS FIP CRATE Sensors/actuators

MTB was based on the PXI platform by National Instruments The PXI rack houses: 1. A controller by NI running on Win XP 2. Two FIP communication cards 3. A 276 x 8 matrix module by Pickering 4. One programmable resistor module by Pickering 5. Power supply card 6. Multimeter card 7. GPIB interface Apart from PXI, other components are: 1. Keithley 2400 SourceMeter 2. Keithley 2182 NanovoltoMeter 3. A connector panel 4. One UPS

Types of cards and transducers: 1. DI – valve card 2. TT/PT/LT cards – temperature, pressure and level transducers cards 3. FIP card – each consist of 2 FIP agents (left for sensors and right for actuators) 4. EH cards – electrical heaters cards Purpose of the tests was to verify that each instrument: 1. was physically present at the machine 2. was correctly wired and properly connected 3. had the expected resistance value

Temperature Pressure  Temperature transducer TT  Two types: CERNOX and Pt100  pinout: subD 9 (M) and fisher 12 (M)  4-wire resistance test  Resistance between U+ and I+  Pressure transducer PT  Types: 20 bar, 4 bar, 350 mbar  pinout: subD 9 (M) and 6 MIL (M)  4-wire resistance test  Resistance between U+ and I+  Resistance on Pt1000  Short circuit against the ground Helium level  Level transducer LT  Probes lengths: 150mm, 400mm, 600mm  pinout: subD 9 (F) and 4 MIL (M)  4-wire resistance test  Resistance between U+ and I+

1. to track down every electrically measurable error within a cable - instrument assembly. (open or inverted connections, short circuits and low insulation resistance values) 2. MTB measured the resistance between all pin combinations of a cable connector and the resistance between each pin of the connector and ground 3. In principle, only measurements between active pins (U+, U-, I+, I-) that belong to the same sensor produced relatively low resistance values. All other combinations implied an open circuit (any resistance value above 1MOhm was considered open circuit)

to validate the correct functionality of each electronic card of the crate. TT/PT card example 1. TT/PT cards are able to measure TT or PT 2. TT/PT cards measure the attached sensor using the 4 wire method 3. CERNOX resistance ranges from some ohms at ambient temperature to tens of kOhm at cryogenic temperatures. TT cards have 3 measuring ranges: – 300 Ohm (excitation current 100uA) – 3 kOhm (excitation current 10uA) 3. 3k – 30 kOhm (excitation current 1uA) TT card test consist of 9 set-points 3 for each range Measurement procedure: 1. The setpoint resistance is set in the programmable resistor module. 2. The matrix connects the resistance to the MTB instrumentation (Keithleys ). 3. The Keithleys perform a measurement of the resistance (Bench Measurement). 4. The matrix disconnects the resistance from the Keithleys and connects it to the TT card under test through the MTB cable that is plugged to the crate card. 5. The TT card performs measurements of the resistance (multiple times per second). MTB acquires measurement data through FIP (FIP Measurement). 6. MTB software compares the two values (Bench Measurement and FIP Measurement). The step is marked as “OK” if the relative error is less than 0,3%.

Low pressure bench – on the right Climatic chamber (temperature module of pressure bench) – on the left

LPB is based on the PXI platform by National Instruments The PXI rack houses: 1. An embedded controller by NI running on Windows XP 2. Multimeter card 3. GPIB interface Apart from PXI, other components are: 1. Two pressure gauges with different ranges allow to perform high accuracy tests from near 0mbar to 130mbar 2. PLC controller for controlling four electromagnetic valves 3. Three pumps (one is turbomolecular pump) 4. 5 DMM’s 5. Power supply system Software: 1. LabVIEW for controlling all system; modular structure for reusability in other projects (temperature, pressure, PID, sequencer) 2. MatLab for data analyses

HPB is based on the PXI platform by National Instruments The PXI rack houses: 1. An embedded controller by NI running on Windows XP 2. Multimeter card 3. GPIB interface Apart from PXI, other components are: 1. Two pressure gauges with different ranges allow to perform tests - from pressure near 50mbar to 20bar 2. Three electromagnetic valves 3. Pumps and bottle with synthetic air Software: 1. LabVIEW for controlling system