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Diffuser Control Logic. Marco Apollonio, Univ. of Oxford. 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)
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Diffuser Control Logic Marco Apollonio, Univ. of Oxford CM18, RAL - UK - 13/06/2007
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 -15 0 +15 CM18, RAL - UK - 13/06/2007
movements & positioning CM18, RAL - UK - 13/06/2007
encoder MICE axis 5 optical sensors to check disc position (4) + disc presence (1) CM18, RAL - UK - 13/06/2007
4 bit ~Gray code When this bit is 1 we sense the disc CM18, RAL - UK - 13/06/2007
mS1 2 m-switches (check if disc at bottom of TH) 1 optical sensor (check if disc at top of TH) Pb disc + frame catcher mS2 OS CM18, RAL - UK - 13/06/2007
OS: carousel and disc encoder OS: disc holder CM18, RAL - UK - 13/06/2007
in progress! logic & control CM18, RAL - UK - 13/06/2007
NAMING CONVENTIONS • Motor A : CAROUSEL (+A, clockwise; -A, counterclockwise) • “ B : DISC HOLDER(s) (+/-B=+/-15deg) • “ C : CATCHER (+C= in, -C=out) CM18, RAL - UK - 13/06/2007
Diffuser Control Flow Chart:main cycle Start: go to Nf (mS1&&mS2) off? NB: need to know WHICH disc is in ! OS on? Which disc is in? Nd Nd = 0 OS on? Move C to position Nd STOP !!! ERROR Extract disc align disc holder: motor CW (+15 deg abs) Move catcher to bottom align disc holder: motor ACW (-15 deg abs) Move catcher to bottom Move C to position Nf Go to dummy station Move Catcher to top Insert disc Command: set disc-f for run mode Go to dummy station STOP CM18, RAL - UK - 13/06/2007
START 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 Ns=1 NT=0, Ne=0 GO TO position Ns Sense disc Record station (Ns: 0,1) If 0 Ne=Ne+1, Nd=Ns If 1 NT=NT+1 Ns=Ns+1 Ne<=1? Ns>=6 STOP !!! ERROR Go to dummy station CM18, RAL - UK - 13/06/2007
START Diffuser Control Flow Chart: move C to position Nd • release BR-PIN Rotate CAROUSEL C.W. (till OS fires Nd) Turn ON motor (+A) OS firing on mark Nd? t>3 s? OS reads Nd? • STOP motor (A) • Push BR-PIN • Start timer STOP STOP !!! ERROR CM18, RAL - UK - 13/06/2007
START Diffuser Control Flow Chart:Extract Disc Align disc holder(s) turn motor CW +15deg abs • Pull linear stage OUT = turn motor on (-C) • Activate TIMER (check extraction time t) t > 5 s? Unlock catcher: turn motor ACW -15deg (mS1 && mS2) off? N Encoder reads -30? Y STOP !!! ERROR OS on? Update DISC position in memory CTRL program Turn C-motor off NB motor be stiff/stable STOP CM18, RAL - UK - 13/06/2007
START Diffuser Control Flow Chart:Insert Disc Unlock circular plate: Turn motor CW +15 deg Encoder +30? • Turn B-motor off (B) • Turn on (+C): • Push linear stage • Activate timer Turn C-motor off Register DISC POSITION in memory for the CTRL PROGRAM t > 5 s? OS off? STOP !!! ERROR STOP (mS1 || mS2) on? N Y CM18, RAL - UK - 13/06/2007
Conclusion • control for diffuser based on optical sensors and mechanical m-switches • design nearly finished • logic in progress CM18, RAL - UK - 13/06/2007