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GRAFCET — Cleanroom Material Airlock

A pharmaceutical pass-through airlock where the HEPA purge and the UV-C dose run concurrently under a double bar, the doors are interlocked by set and reset actions rather than by wiring alone, and a differential-pressure check diverges alternatively to a quarantine loop when the cascade or the particle count fails.

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Cleanroom material airlock — pass-throughSteps111 initial · 0 finalTransitions11every one conditionedDivergences1 AND · 1 ORsimultaneous · alternativeAlternationWell formedsteps and transitions alternate1Both doors closed, airlock idleNBoth doors lockedNCascade pressure hold2Unlock grey-side doorRBoth doors lockedNGrey door unlockSWhite door interlock3Load material, close doorNLoad permitted lampNLoad cell weight check4HEPA purge of chamberNPurge fan at full flowL90sPurge timer5UV-C decontaminationNUV-C lamps onL120sUV dose timer6Purge done, cascade restoredRPurge fan at full flowNCascade pressure hold7UV lamps off, coolingRUV-C lamps onD15sLamp cool-down8Verify differential pressureNDP transmitter pollD5sSettling time9Unlock white-side doorRWhite door interlockNWhite door unlockNTransfer permitted lamp10Close white door, re-lockSBoth doors lockedNCascade pressure hold11Quarantine, re-purgeSQuarantine alarm latchedNPurge fan at full flowgrey_request . chamber_empty . white_door_closedgrey_door_opengrey_door_closed . load_presentpurge_timer_done . particle_count_okuv_dose_donecascade_ok . lamps_cooldp >= 15 Pa . particle_count_okdp < 15 Pa + /particle_count_okwhite_door_open . load_removedwhite_door_closedre_purge_done . operator_ack11 steps · 11 transitions · 24 actions · 1 simultaneous · 1 alternative divergenceSteps and transitions alternate on all 24 links.Step 1 is the single initial step.1 simultaneous divergence is closed by a convergence of the same width.

Make it your own.

title "Cleanroom material airlock — pass-through"

step 1 "Both doors closed, airlock idle" initial
  N "Both doors locked"
  N "Cascade pressure hold"
step 2 "Unlock grey-side door"
  R "Both doors locked"
  N "Grey door unlock"
  S "White door interlock"
step 3 "Load material, close door"
  N "Load permitted lamp"
  N "Load cell weight check"
step 4 "HEPA purge of chamber"
  N "Purge fan at full flow"
  L 90s "Purge timer"
step 5 "UV-C decontamination"
  N "UV-C lamps on"
  L 120s "UV dose timer"
step 6 "Purge done, cascade restored"
  R "Purge fan at full flow"
  N "Cascade pressure hold"
step 7 "UV lamps off, cooling"
  R "UV-C lamps on"
  D 15s "Lamp cool-down"
step 8 "Verify differential pressure"
  N "DP transmitter poll"
  D 5s "Settling time"
step 9 "Unlock white-side door"
  R "White door interlock"
  N "White door unlock"
  N "Transfer permitted lamp"
step 10 "Close white door, re-lock"
  S "Both doors locked"
  N "Cascade pressure hold"
step 11 "Quarantine, re-purge"
  S "Quarantine alarm latched"
  N "Purge fan at full flow"

transition t1 : "grey_request . chamber_empty . white_door_closed"
transition t2 : "grey_door_open"
transition t3 : "grey_door_closed . load_present"
transition t4 : "purge_timer_done . particle_count_ok"
transition t5 : "uv_dose_done"
transition t6 : "cascade_ok . lamps_cool"
transition t7 : "dp >= 15 Pa . particle_count_ok"
transition t8 : "dp < 15 Pa + /particle_count_ok"
transition t9 : "white_door_open . load_removed"
transition t10 : "white_door_closed"
transition t11 : "re_purge_done . operator_ack"

1 -> t1 -> 2 -> t2 -> 3 -> t3

# Purge and UV dose run at the same time and the chamber is only released
# when BOTH have finished: SIMULTANEOUS, double bar, matched convergence.
simultaneous t3 -> 4, 5
4 -> t4 -> 6
5 -> t5 -> 7
simultaneous 6, 7 -> t6
t6 -> 8

# Cascade and particle count either prove or they do not: ALTERNATIVE,
# single bar, with the failure branch looping back to the verification.
alternative 8 -> t7, t8
t7 -> 9
t8 -> 11
11 -> t11 -> 8

9 -> t9 -> 10 -> t10 -> 1