TE-MPE-TM 25/10/2012, ELQA team TP4 System – the main tool for ELQA Mateusz Bednarek, CERN, Geneva Jaromir Ludwin, IFJ-PAN, Krakow

TE-MPE-TM 25/10/2012, ELQA team ELQA prior to the Powering Tests All possible ELQA scenarios are described in EDMS document Main part of ELQA activities was marked in black.

TE-MPE-TM 25/10/2012, ELQA team ELQA campaign Tests are divided into 3 groups: TP4 – Test Procedure 4 o HV and LV tests of circuits powered via DFBs o 743 circuits DOC – Dipole Orbit Corrector check o HV and LV tests of circuits powered locally o 914 circuits MIC – Magnet Instrumentation Check o HV and LV tests done locally on each magnet – it includes quench heater qualifications o 1763 magnets. TP1, TP2, TP3 were the test procedures suitable for testing DFBs at different stages of assembly. TP4 is the last test procedure that shall be applied once the DFB are connected to the magnet chain.

TE-MPE-TM 25/10/2012, ELQA team Typical circuit tested with TP4 2 current leads Magnet chain We need to check: Electrical insulation of the circuit, Continuity and resistance of the circuit, Continuity and resistance of V-taps, Check if V-taps are properly distributed along the CLs. Make sure that the Pt100 is properly attached to the CL potential (to be implemented)

TE-MPE-TM 25/10/2012, ELQA team Complexity issue For the MIC test there are 23 different types of magnets. The TP4 and DOC tests are even more varied o 2-4 current leads in one circuit, o 7 types of current leads, o 6 types of connectors on DFBs

TE-MPE-TM 25/10/2012, ELQA team Complete system overview A universal measurement system is needed to cover all configurations Measurements have to be automated Results must be stored in the central database Follow-up web page should be available as well

TE-MPE-TM 25/10/2012, ELQA team Complete system overview

TE-MPE-TM 25/10/2012, ELQA team The TP4 System The TP4 system was recently upgraded by the team from IFJ-PAN (aka HNINP), Krakow o The hardware of the old system was unmaintainable o There were not enough spares o The old system was entirely dependent on the Keithley multimeter o The stability parameters of the old system were acceptable, but there was a lot of room for improvement o Many additional features were added in the upgraded version In this presentation we will focus on the current version of the system

TE-MPE-TM 25/10/2012, ELQA team Hardware – general architecture

TE-MPE-TM 25/10/2012, ELQA team Hardware Measurement of the ohmic resistance of the highly inductive superconducting magnet, requires extremely stable current. Using voltage source with stable serial resistance gives better results than using current source. In order to stabilise the resistance of the current path within the measurement system, we have decided to thermally stabilise the crucial elements.

TE-MPE-TM 25/10/2012, ELQA team Hardware The resistors are used to set the working point of the power supply and for current measurement. 18 Internal voltage taps are routed to the inputs of the multiplexers.

TE-MPE-TM 25/10/2012, ELQA team The temperature regulation The temperature regulator is based on the microcontroller, connected to the computer via USB port. Regulation is done in two stages: o Temperature of internal part is controlled by proportional- integrating regulator using 4 heaters. The current relays PCB and resistors are enclosed in thermally insulated box. o Temperature of external part is controlled by proportional regulator using set of heaters and fan Parameters of regulators are stored in the EEPROM, and can be modified from the level of LabVIEW software. Since we know the power that will appear on the resistors during the measurement, we can use feed-forward method to stabilise the temperature of the resistors. The feed-forward control is done by altering the integral term of PI regulator.

TE-MPE-TM 25/10/2012, ELQA team Hardware The system is equipped with 84 inputs: 18 internal, 66 available on the front panel. Having 4 independent 1 of 84 multiplexers gives following possibilities: Measurements of any two voltages inside the system and on the device under test 4-wire resistance measurements Transfer function measurements using freely chosen reference impedance

TE-MPE-TM 25/10/2012, ELQA team PCBs arrangement Multiplexers are fitted into a 3U crate, Power supply is located in a separate 1U case

TE-MPE-TM 25/10/2012, ELQA team Shielding

TE-MPE-TM 25/10/2012, ELQA team Current status of the system All multiplexer crates are assembled and tested, Measurement instruments are mounted on the available trolleys, Most of the measurement cables are ready, During the development of the system emerged an idea of replacing Keithley multimeter with two PXI DMM cards. o The migration is ongoing o SM18 tests have shown that the migration is not going to be too complicated

TE-MPE-TM 25/10/2012, ELQA team Debug console Apart of the standard measurement applications (TP4, DOC, MIC) there is a “debug console” Access to all the measurement instruments in the system, Low level control of the multiplexers and the thermostats, Usage of functionalities inaccessible for standard applications, System self testing capability, Advanced circuit diagnostics, Designed to be used by experts only.

TE-MPE-TM 25/10/2012, ELQA team Software Database is the central part of the system. It stores: Reference data describing circuits Test content Validation conditions Configuration parameters Calibration parameters Results Signal translation in low voltage test applications.Measurement results validation process.

TE-MPE-TM 25/10/2012, ELQA team Open question During the MIC tests, we are powering the measurement system form 24 VDC batteries of Pefra tractor. There are rumours, that the tractor type at CERN may change. In such case we would have to adapt our hardware and the work flow. Source: Model 507 datasheet

TE-MPE-TM 25/10/2012, ELQA team Conclusions TP4 is a very versatile system perfectly suited for the complex LHC circuits, Upgrade works are almost finished, If needed the TP4 platform may be used for new types of measurements, The database system makes it a reliable and scalable system, A test on a highly inductive superconducting magnet is still missing

TE-MPE-TM 25/10/2012, ELQA team Acknowledgements The new TP4 is a very complex project. Many details had to be carefully designed in order to achieve expected performance, both from electrical and mechanical points of view. Credit for solution of those problems goes mainly to the IFJ-PAN team: Piotr Jurkiewicz, Marek Ruszel, Ryszard Tarczoń and others, who are not mentioned here, but realisation of this project would be impossible without them.

TE-MPE-TM 25/10/2012, ELQA team Thank you for your attention!

TE-MPE-TM 25/10/2012, ELQA team Back-up slides For the discussions

TE-MPE-TM 25/10/2012, ELQA team Keithley -> PXI controversy Pros of having a PXI on board o Reduction of time needed for the measurements, o Increased precision as the current can be measured at the same time as the voltage across a component of the circuit, o Decreased wear of the multiplexer relays, o Increased versatility of the system Cons o Increased complexity of the user interface, o Communication with the central DB will need to be modified

TE-MPE-TM 25/10/2012, ELQA team Example screenshots