Midterm Review 2006-04-11 1 MBS 2006 MP Electronics, Basic Concept Two modules: Probe module ...

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MP Electronics, Basic Concept

Two modules:

Probe module

Surface module

The surface module is replaced by the Interface Module and COTS components

Detailed data processing is performed by the surface module (GSE)

Controller inside probe module performs measurement and heater control tasks

Power supply and communication via the tether

Power provided by standard laboratory power supply

Standard interface for communication: USB

In terface M odule

Probe M odule

Laboratory Power Supply

Tether

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MP Electronics Module (1)

Dedicated electronics department inside the probe

Cylindrical tube with top and bottom cover

Three braces at 120° position provide the fixation of the PCB's

Braces are used to fix the electronics compartment inside the probe

Fixed connector at top cover provides the interface to the tether

Pig-tails (TBC) located at the bottom cover provide the interface to the heaters and sensors

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Power conditioner

Controller

Communication

Signal conditioning

Heater Control

M elt in g Pro b e Electro n ics

DC-DC5 Volts

ControllerCommunication

Heater Control

Signal Conditioning

D +

D -

Hea

ter

1

Hea

ter

5

Tether

Pt1

00 1

Pt1

00 9

P H S ensor

Two A xisTilt S ensor

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Circuit diagrams not fully completed Electronics will be spread to 5...6 PCB's (55mm diameter) Connection to tether and external heaters and sensors via MDM

connector PCB interconnection via spring contacts and gold plated pads

M elt in g Pro b e Electro n ics

Power Module

Communication Module

Heater Control Module

Controller Module

Pt100 S ignal Conditioner

Sensor ModulePH, Tilt, 28V, 5V

2 2

T ether

5V

28V

28V Return

5V Return

2

2

5

5x 2

10

9x3 + 1

Heater 1

Heater 5

Pt100_1

Pt100_9

4

3

2

PH3

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Power Conditioner

Supply via the tether with 28V (laboratory power supply)

Use of two redundant pairs (AWG ?)

High power Schottky diodes at +28V input

Heaters directly supplied from 28V

DC/DC converter 28V / 5V to supply electronics

Linear regulator to generate supply voltage for Ph sensor

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Controller

Prototype is based on PIC18F4550

Frequency: up to 40MHz, inbuilt 8MHz clock

Program memory: 32KByte

Data memory: 16kByte

ADC: 10 bit, 13 channels, 5V range

On-chip USB interface

44-pin TQFP plastic package

Operational temperature range: -40°C...+85°C

Storage temperature range: -65°C...+150°C

Wide supply voltage range

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Communication

The communication channel uses the same signal lines as the power supply

Binary frequency shift key modulation for signal transmission will be used

Use of two carrier frequencies to support full-duplex mode

The communication will be based on the USB protocol

Frequencies not yet selected

Detailed design not yet finished

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Heater Control

Large variation of impedance due to environmental condition Individual current limiter for each heating segment Power management to minimize EMC radiation and losses

Heating segments switched sequentially

Concept for power sharing in low power mode under investigation

Control loop activated every 10ms (TBC) Dedicated bang-bang controller with adjustable nominal

temperature for each segment Highest priority is given to front segment, while rear segment

has lowest priority Electronics calculates duty-cycle for each heater segment

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Temperature Measurement

Measurement shall support a temperature range between -200°C and +100°C

Five Pt100 are dedicated to the heater segments, four additional sensors are available for individual measurements

Pt100's are supplied with constant current of 1mA

Four wire interface is important since impedance of Pt100 varies from approx. 20Ω to 140Ω

Common GND line to save connector pins (three wire interface)

Resolution approx. 0.5°C/digit

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Analogue & Digital Measurements

C h a n n e l S ig n a l R a n g e Vo lta g e R e m a rk

AC H 0 1 P t 1 0 0 H e a te r 1 -2 0 0 ...+1 0 0 °C 0 .1 ... 4 .9 V U se d fo r co n tro l lo o p





AC H 0 6 P t1 0 0 -2 0 0 ...+1 0 0 °C 0 .1 ... 4 .9 V

AC H 0 7 P t1 0 0 -2 0 0 ...+1 0 0 °C 0 .1 ... 4 .9 V

AC H 0 8 P t1 0 0 -2 0 0 ...+1 0 0 °C 0 .1 ... 4 .9 V

AC H 0 9 P t1 0 0 -2 0 0 ...+1 0 0 °C 0 .1 ... 4 .9 V

AC H 1 0 P t1 0 0 E le ctro nics -2 0 0 ...+1 0 0 °C 0 .1 ... 4 .9 V

AC H 1 1 PH se n so r

AC H 1 2 2 8 Vo lts

AC H 1 3 +5 Vo lts

C h a n n e l S ig n a l R a n g e C o u n te r R e m a rk

D C H 01 T ilt sensor X T1 0...1 0m s D uty cyc le

D C H 02 T ilt sensor X T2 0...1 0m s Total period

D C H 03 T ilt sensor Y T1 0...1 0m s D uty cyc le

D C H 04 T ilt sensor Y T2 0...1 0m s Total period

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Communication Protocol

Data are sent only on request

A response is send for each command, either simple ACK/NACK or data-set

Commands:

Set the nominal value for the control loop

Requests the temperature values

Requests all measurement values

Requests the nominal temperatures for the control loops

Request duty cycle

Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 H eader C om m and

Length C om m and Identifie r

Param eter 1 Param eter 2 Param eter 3

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Data-Set

Acknowledge / Not acknowledgeNACK will include simple failure code

Temperature dataThe temperature value for all five heater segments

All measurement dataA complete of measured data, temperatures, tilt angles and Ph value

Nominal temperature valuesRead-back of the reference values for the heater control loops

Duty cycleActive time of a heater during 1sec time periodResolution 1% (TBC)Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7 Byte

2N +6

xx PacketLength = 6+2N

C m d-ID + AC K

N O_Error

Spare Spare Value 1 H igh byte

... Va lue N Low byte

Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6

H eader 06 C m d-ID + AC K Error code or N O_Error

Spare Spare

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Software Design

Design based on Ward-Mellor method

Implementation with the MPE Lab IDE

Coding in C based on the Microchip C18 compiler

USB driver provided by Microchip

Measurement of analogue signals (Pt100 & Ph) by use of inbuilt ADC

Measurement of digital signals (tilt sensor) by use of capture/compare registers

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Software Interfaces

In te rn a l H W In te rru p ts

P ro g ra m m Fla sh-PR OM

0M elting P robe SW

U SB In te rru p ts

U SBSta tu s & C o n tro l R e g iste rs

U SB R AM

ADC Interface

USB-Interface

PIC 1 8FxxxS ta tu s & C o n tro l R e g iste rs

In te rn a l H WC o n tro l R e g iste rs

internal HardwareT im er, H LVD , ...

CCP/PWM Interface

Po rt x

I/O Ports

AD C In te rru p ts

AD CSta tu s & C o n tro l R e g iste rs

AD C R e su lt R e g iste r

9 x Pt100, 1 x PH sensor, 1x 28V, 1X 5V

C C P/PW M In te rru p ts

C C P/PW MSta tu s & C o n tro l R e g iste rs

Tim e r R e su lt R e g iste r

2 x T ilt sensor

5 x H eater On / Off

C CP / PW M

Inter rupts

PIC 18F xxxC ontro l & Status

In te rn a l R AM

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Software, Decomposition Level 0

2Communicate

via USB

4Measure

3Control Heaters

1ControlSystem

AD CInterruptsA DCCo ntr ol & Sta tusAD CR es ult

I/O Por t

C CP / PWM

Inter rupts

CCP / PW M

C on tro l & S tatu s

PW M

Result

USB

In terr up ts

U SBC ontro l & Status

U S BDa ta

in te rnal HW

IR Q s

F lash-PR OM data

Internal HW

C ontrol & S ta tus

P IC 18Fx xx

C ontro l & S tatus

In ternalRAM

M easured D ata

C om m anded D ata

Midterm Review 2006-04-11 1 MBS 2006 MP Electronics, Basic Concept Two modules: Probe module ...

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Transcript of Midterm Review 2006-04-11 1 MBS 2006 MP Electronics, Basic Concept Two modules: Probe module ...