1 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” Dedicated electronics for fixed points furnaces control Istituto Nazionale di Ricerca Metrologica “New electronics and new Heat Pipes for fixed points” New Heat Pipes for temperature fixed points

2 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points”

3 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” Noise For simplicity we can distinguish two sources of noise:  Noise caused by internal disturbs of the system  Noise caused by external disturbs  These disturbs are, in general, discontinous, accidental and random in time  These disturbs are, in general, continous and periodic in time

4 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” Internal disturbs  Disturbs in ingress of the control system given directly by the action of thermocouples  Problems operating on the system control subsequent to the level of the components that generate the parameters  Magnetic noise produced also by the power supply  Dirsturbs acting on the sensible element that have to be measured given by the furnaces  Problems caused by disturbs resulting by the ground reference loop

5 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” External disturbs  External electromagnetic influences due to humans (for exemple with the use of cellular telephone) due to other instruments in the lab  Mechanical disturbs produced by humans produced by mechanical vibrations  Capacitative induced effects given by external effects (vibrations again)

6 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” Thermal noise Thermal noise is caused by the thermal agitation of charge carriers in a conductor. Burst noise also called popcorn noise, appears to be related to imperfections in semiconductor material and heavy ion implants. Flicker noise Flicker noise is also called 1/f noise. It is present in all active devices that work with low frequency signals and has various origins. Flicker noise is always associated with a DC current, so it is the main noise internal cause. Drift Temperature, ageing and packaging stress cause time-varying offset Lots of noises!

7 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” RF and elettromagnetic interference Magnetic field generated by current flowing in ac power supply at 50 Hz Spikes of voltage by any near device Noise sources affecting thermocouples

8 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” Characterized by Offset Drift 1/fnoise PSRR, CMRR reduction Amplifier behaviour near DC

9 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” Offset and 1/f noise are “inside” the system But we can reduce the offset “enough” by –1.Using “large” devices and good layout –2.Dynamic offset-cancellation (DOC) techniques DOC techniques also reduce 1/f noise!

10 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” Auto-zeroing Sampled data Offset sample, then subtract Chopping Continuous time Modulate offset away from DC Frequently chopping is significantly better than auto-zeroing DOC Techniques

11 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” Existing electronic made at INRiM  A CT 9001 and a CT 9000 modules for  - conditioning thermocouple signal  - reset possible drift  - fine temperature control  An Euroterm commercial controller module is then used to control the power supplied to the furnace

12 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” CT 9000 is an amplifier module that amplifies the signal from thermocouple with a x10, x100, x1000 gain. It is possible a check zero to see the presence of offset and drift. Moreover, it is possible to add to output signal of this module an offset signal EΔ, adjustable in the first fine regulation (±10k) with 2k/cursor number; in ultra-fine regulation, for each number it is possible to adjust of 0.2k/cursor step. For second fine regulation (±2.5k) it is possible to adjust at 0.5k/cursor number and in ultra-fine regulation, for each number it is possible to adjust at 0.05k/step level. CT9000

13 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” The module CT 9001 is used to adjust possible offsets and drift from thermocouple and from the CT 9000 CT9001

14 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” Design of temperature controller Design of temperature controller Design of temperature controller Design of temperature controller Implementation of micro-controller inside software Implementation of micro-controller inside software Implementation of micro-controller inside software Implementation of micro-controller inside software Realization of the system Realization of the system Realization of the system Realization of the system Performances evaluation Performances evaluation Performances evaluation Performances evaluation Actions

15 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” Temperature control fine wide I/O devices Parameters setting Data visualization Remote PC control Specifications

16 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points”

17 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points”

18 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” Thermocouple output voltage is amplified by a low noise amplifier (LNA), converted in a digital signal and sent to the micro-controller. The micro-controller compares the voltage/temperature value with a reference value and supply the power in the furnace with the pulse width modulation (PWM) technique Software

19 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” PWM (Pulse Width Modulation ) is a technique that modules a wave squares varying duty cycle of them. PWM Power control

20 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” The software will be developed in order to reach the complete control of the electronics, I/O interfacing and routines. It allows to set the specific requirements by selecting: –Type of input sensor and temperature range –Control algorithm needed (PID) –Number and type of outputs (heat, cool, alarm,) –Scale of application, set points, alarm points. Software

21 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” A firmware, made of several functions, will be written and loaded in the memory inside of micro-controller to satisfy the required specifications. These functions can be called both by on board keyboard and from a PC. Data can be saved and on line graphs can be obtained.

22 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” Heat Pipes and GCHPs

23 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” Temperature stability in a mercury GCHP

24 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” Temperature uniformity in a mercury GCHP

25 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” Fine controlled temperature changes

26 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” The first Gas Controlled Heat Pipe for fixed points

27 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points”

28 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points”

29 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points”

30 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points”

31 Euromet Workshop on Project 732: - CNAM – Paris – November 2006 Andrea Merlone “New electronics and new Heat Pipes for fixed points” We thank you!