m. apollonio CM18, RAL - UK - 13/06/2007 1

Diffuser Control LogicMarco Apollonio, Univ. of Oxford

m. apollonio CM18, RAL - UK - 13/06/2007 2

• 3 main movements & accurate positioning

– Carousel (revolving)– Discs (+/- 15 deg)

• Unload disc holder / load catcher (+15, +15)• Unload catcher / load disc holder (-15, -15)

– Catcher (linear motion through a threaded cylinder)

• Sequence of operations & Control

0+15

-15

m. apollonio CM18, RAL - UK - 13/06/2007 3

movements & positioning

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5 optical sensors to check disc position (4) +disc presence (1)

MICE axis

encoder

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4 bit ~Gray code

When this bit is 1 we sense the disc

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2 -switches(check if disc at bottom of TH) 1 optical sensor(check if disc at top of TH)

S1

S2

OS

catc

her

Pb

disc

+ fr

ame

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OS: carousel and disc

OS

: disc holder

encoder

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m. apollonio CM18, RAL - UK - 13/06/2007 9

logic & control

in progress!

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NAMING CONVENTIONS

• Motor A : CAROUSEL (+A, clockwise; -A, counterclockwise)

• “ B : DISC HOLDER(s) (+/-B=+/-15deg)

• “ C : CATCHER (+C= in, -C=out)

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Start: go to Nf

(S1&&S2) off?

OS on?

OS on? Which discis in? Nd

Move C to position Nd

Nd = 0

Extract disc

Move catcher to bottom

Move C to position Nf

Insert disc

Go to dummy station

STOP

Move Catcher to top

STOP !!!ERROR

align disc holder:motor ACW (-15 deg abs)

align disc holder:motor CW (+15 deg abs)

Move catcher to bottom

Go to dummy station

Command: set disc-f for run mode

NB: need to know WHICH disc is in !

Diffuser Control Flow Chart:main cycle

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Diffuser Control Flow Chart:

check discs insertedat the end of this cycle I should have a 5-element vector like (1,1,1,0,1) telling which station is empty. If the number

of empty stations (Ne) is greater than 1 an error is produced which stops the

system

Sense disc

START

GO TO position Ns

Record station (Ns: 0,1)If 0 Ne=Ne+1, Nd=Ns

If 1 NT=NT+1

Ns=1NT=0, Ne=0

Ns>=6

Ns=Ns+1

Go to dummy station

Ne<=1?

STOP !!!ERROR

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Diffuser Control Flow Chart:

move C to position NdRotate CAROUSEL C.W.

(till OS fires Nd)Turn ON motor (+A)

STOP

START

OS firing on mark Nd?

1. STOP motor (A) 2. Push BR-PIN3. Start timer

1. release BR-PIN

t>3 s?

OS reads Nd?

STOP !!!ERROR

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Diffuser Control Flow Chart:Extract Disc

STOP

START

t > 5 s?

1. Pull linear stage OUT = turn motor on (-C)2. Activate TIMER (check extraction time t)

S1 && S2) off?

STOP !!!ERROR OS on?

Turn C-motor offNB motor be stiff/stable

Unlock catcher: turn motor ACW -15deg

Encoder reads -30?

Update DISC position in memory CTRL program

Y

N

Align disc holder(s)turn motor CW +15deg abs

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Diffuser Control Flow Chart:Insert Disc

STOP

START

Encoder +30?

Unlock circular plate:Turn motor CW +15 deg

STOP !!!ERROR

Turn B-motor off (B)Turn on (+C):

• Push linear stage• Activate timer

t > 5 s?

OS off?

Register DISC POSITION in memory for the CTRL PROGRAM

S1 || S2) on?

Turn C-motor off

Y

N

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Conclusion

• control for diffuser based on optical sensors and mechanical -switches

• design nearly finished

• logic in progress

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