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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 November 2006

Andrea Merlone

“New electronics and new Heat Pipes for fixed points”

Dedicated electronics Dedicated electronics for fixed points for fixed points furnaces controlfurnaces control

Istituto Nazionale di Ricerca Metrologica

“New electronics and new Heat Pipes for fixed

points”

New Heat Pipes for New Heat Pipes for temperature fixed temperature fixed

pointspoints

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 November 2006

Andrea Merlone

“New electronics and new Heat Pipes for fixed points”

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 November 2006

Andrea Merlone

“New electronics and new Heat Pipes for fixed points”

NoiseFor 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 andperiodic in time

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 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

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 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)

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 November 2006

Andrea Merlone

“New electronics and new Heat Pipes for fixed points”

• Thermal noiseThermal noise is caused by the thermal agitation of charge carriers in a conductor.

• Burst noisealso called popcorn noise, appears to be related to imperfections in semiconductor material and heavy ion implants.

• Flicker noiseFlicker 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.

• DriftTemperature, ageing and packaging stress cause time-varying offset

Lots of noises!

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 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

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 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

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 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!

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 November 2006

Andrea Merlone

“New electronics and new Heat Pipes for fixed points”

Auto-zeroingSampled dataOffset sample, then subtract

ChoppingContinuous time

Modulate offset away from DC

Frequently chopping is significantly better than auto-zeroing

DOC Techniques

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 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

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 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

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 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

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 November 2006

Andrea Merlone

“New electronics and new Heat Pipes for fixed points”

Design of temperature controller Design of temperature controller Implementation of micro-controller inside Implementation of micro-controller inside

software software Realization of the systemRealization of the system Performances evaluationPerformances evaluation

Actions

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 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

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 November 2006

Andrea Merlone

“New electronics and new Heat Pipes for fixed points”

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 November 2006

Andrea Merlone

“New electronics and new Heat Pipes for fixed points”

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 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

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 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

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 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

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 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.

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 November 2006

Andrea Merlone

“New electronics and new Heat Pipes for fixed points”

Heat Pipes and GCHPs

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 November 2006

Andrea Merlone

“New electronics and new Heat Pipes for fixed points”

120 kPa

-2,5

-2

-1,5

-1

-0,5

0

0,5

1

1,5

2

2,5

0.00.00 0.14.24 0.28.48 0.43.12 0.57.36 1.12.00 1.26.24 1.40.48 1.55.12

Time / h.min

Tem

pe

ratu

re d

iffe

ren

ce

/ m

K

Temperature stability in a mercury GCHP

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 November 2006

Andrea Merlone

“New electronics and new Heat Pipes for fixed points”

120 kPa

-60

-50

-40

-30

-20

-10

0

10

0 5 10 15 20 25 30

Distance from the bottom / cm

Tem

pe

ratu

re d

iffe

ren

ce

/ m

KTemperature uniformity in a mercury GCHP

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 November 2006

Andrea Merlone

“New electronics and new Heat Pipes for fixed points”

120 kPa

-5

0

5

10

15

20

25

30

35

40

45

0.00 0.28 0.57 1.26 1.55 2.24 2.52 3.21 3.50

Time / h.min

Tem

per

atu

re d

iffe

ren

ce /

mK

Fine controlled temperature changes

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 November 2006

Andrea Merlone

“New electronics and new Heat Pipes for fixed points”

The first Gas Controlled Heat Pipe for fixed points

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Euromet Workshop on Project 732: - CNAM – Paris – 23-24 November 2006

Andrea Merlone

“New electronics and new Heat Pipes for fixed points”

28

Euromet Workshop on Project 732: - CNAM – Paris – 23-24 November 2006

Andrea Merlone

“New electronics and new Heat Pipes for fixed points”

29

Euromet Workshop on Project 732: - CNAM – Paris – 23-24 November 2006

Andrea Merlone

“New electronics and new Heat Pipes for fixed points”

30

Euromet Workshop on Project 732: - CNAM – Paris – 23-24 November 2006

Andrea Merlone

“New electronics and new Heat Pipes for fixed points”

31

Euromet Workshop on Project 732: - CNAM – Paris – 23-24 November 2006

Andrea Merlone

“New electronics and new Heat Pipes for fixed points”

We thank you!