Kugwiritsa ntchito PLC mu Kuwongolera Njira
Mu dziko lamakono la mafakitale, kufunikira kwa machitidwe olamulira odalirika, achangu, komanso opangidwa mosavuta kukupitirira kukula. Makampani akuyenera kusunga khalidwe la malonda, kuwonjezera magwiridwe antchito, ndikuchepetsa nthawi yogwira ntchito yopanga. Chimodzi mwa ukadaulo womwe umagwiritsidwa ntchito kwambiri kuti ukwaniritse zosowa izi ndi PLC (Programmable Logic Controller). Ma PLC ndi "ubongo" wa mizere yambiri yopangira - makina owongolera, masensa owunikira, komanso kuchita zokha malingaliro a njira. Nkhaniyi ikufotokoza momwe ma PLC amagwiritsidwira ntchito powongolera njira, zigawo zawo zazikulu , momwe amagwirira ntchito, zabwino zawo, zovuta, ndi zitsanzo za momwe amagwiritsidwira ntchito m'munda.
1. Kodi PLC ndi chiyani?
PLC ndi chipangizo chowongolera cha digito chopangidwa pogwiritsa ntchito microprocessor chomwe chimapangidwira mafakitale. Mosiyana ndi makompyuta achikhalidwe, ma PLC adapangidwa kuti athe kupirira kugwedezeka, kutentha kwambiri, fumbi, ndi kusokonezedwa ndi magetsi. Ma PLC amalowa m'malo mwa machitidwe owongolera achikhalidwe opangidwa pogwiritsa ntchito relay (relay logic), omwe nthawi zambiri amakhala ovuta, ovuta kusintha, ndipo amafuna mawaya ambiri.
Ma PLC amatha kukonzedwa kuti agwire ntchito zosiyanasiyana zowongolera, kuyambira pa ntchito zosavuta monga kuyambitsa mota kutengera zizindikiro za sensor, mpaka njira zovuta monga kuwongolera kutentha, kupanikizika, kapena kuyenda kwa zinthu zomwe zimakhudza magawo ambiri.
2. Udindo wa PLC pa Kuwongolera Machitidwe
Kuwongolera njira ndi ntchito yowongolera zosintha za njira (monga kutentha, kuthamanga, kuchuluka kwa madzi, kuchuluka kwa kayendedwe ka madzi, liwiro la injini) kuti zikwaniritse zomwe mukufuna. PLC imagwira ntchito ngati wolamulira wamkulu, yemwe:
1. Landirani zizindikiro kuchokera ku masensa (zolowera) monga masensa oyandikira, ma switch oletsa, ma RTD/thermocouple, ma flow meter, ma pressure transmitters, kapena masensa a level.
2. Ndondomeko/mapulogalamu otsatira njira zolowera, malo okhazikitsira, ndi ma algorithm owongolera.
3. Tumizani malamulo ku ma actuator (zotulutsa) monga ma solenoid valves, ma starter motors, ma inverter/VFDs, ma heaters, mapampu, kapena ma alarm.
4. Kulemba ndi kutumiza deta ku machitidwe ena monga HMI (Human Machine Interface), SCADA (Supervisory Control and Data Acquisition), kapena DCS kudzera mu njira zolumikizirana zamafakitale.
Ndi luso limeneli, PLC imakhala njira yofunika kwambiri pakusunga kusinthasintha kwa njira ndi kukhazikika kwa kupanga.
3. Zigawo Zazikulu za PLC
Kawirikawiri, PLC ili ndi magawo angapo ofunikira:
– CPU (Central Processing Unit): Imachita ntchito yokonza mapulogalamu ndikuwongolera kupanga zisankho.
– Mphamvu Yopereka Mphamvu: Imapereka mphamvu ya gawo la PLC.
– Gawo Lolowera: Limalandira zizindikiro za digito/analog kuchokera ku masensa. Kulowetsa kwa digito nthawi zambiri kumakhala koyatsidwa/kuzima, pomwe kulowetsa kwa digito nthawi zambiri kumakhala koyatsidwa/kuzima. chizindikiro cha analogi 4–20 mA kapena 0–10 V.
– Chotulutsa Chotulutsa: Chimatumiza zizindikiro za digito/analog kuti ziwongolere ma actuator.
– Memory: Imasunga mapulogalamu ndi deta yokonza.
- Gawo Lolumikizirana: Limathandizira maukonde a mafakitale monga Modbus, Profibus, Profinet, Ethernet/IP, CANopen, ndi zina zotero.
Kutengera zosowa, ma PLC akhoza kukhala ang'onoang'ono (onse-mu-chimodzi) kapena ma modular units omwe angathe kukulitsidwa mosavuta ndi I/O.
4. Momwe PLC Imagwirira Ntchito : Kujambula Sikena
PLC imagwira ntchito motsatira mfundo ya kayendedwe ka scan kobwerezabwereza mwachangu kwambiri:
1. Kujambula Kolowera: PLC imawerenga momwe zinthu zonse zolowera zilili.
2. Kusanthula Pulogalamu: PLC imayendetsa dongosolo la pulogalamu kuyambira pamwamba mpaka pansi (kutengera chilankhulo cha pulogalamu).
3. Zosintha Zotuluka: PLC imasintha zotuluka malinga ndi zotsatira za pulogalamuyo.
4. Kusamalira/Kulankhulana: PLC imayang'anira matenda, kulumikizana ndi maukonde, ndi ntchito zina zamkati.
Njirayi imachitika mu ma milliseconds, kotero PLC imatha kuyankha kusintha kwa machitidwe munthawi yeniyeni.
5. Chilankhulo cha Mapulogalamu cha PLC
Ma PLC amapangidwa pogwiritsa ntchito muyezo wa IEC 61131-3. Zilankhulo zina zodziwika bwino ndi izi:
– Chithunzi cha Makwerero (LD): Chodziwika kwambiri, chofanana ndi dera lolumikizirana. Choyenera kugwiritsa ntchito njira yolumikizirana.
– Chithunzi cha Magawo Ogwira Ntchito (FBD): Kugwiritsa ntchito magawo ogwirira ntchito, omwe nthawi zambiri amagwiritsidwa ntchito poyang'anira ma analogi ndi machitidwe.
– Malemba Okonzedwa (ST): Ofanana ndi chilankhulo chapamwamba cha mapulogalamu, choyenera ma algorithms ovuta.
– Tchati cha Ntchito Yotsatizana (SFC): Yoyenera njira zotsatizana monga kupanga ma batches kapena kulongedza.
– Mndandanda wa Malangizo (IL): Umagwiritsidwa ntchito pang'onopang'ono chifukwa ukuyamba kusiyidwa.
Kusankha chilankhulo nthawi zambiri kumasinthidwa kuti kugwirizane ndi zovuta za njira ndi zizolowezi za gulu la mainjiniya.
6. PLC ya Discrete Control ndi Continuous Control
Kugwiritsa ntchito ma PLC pakulamulira njira kungagawidwe m'magulu awiri:
a) Kulamulira Kobisika
Kuwongolera kwapadera kumagwirizana ndi zinthu za ON/OFF. Mwachitsanzo:
- Imayatsa chonyamulira pamene sensa yazindikira chinthu.
- Imayatsa pompu pamene mulingo wa thanki uli wochepa.
- Amatseka loko yotetezera chitseko cha makina chikatsegulidwa.
Ma PLC ndi amphamvu kwambiri pakulamulira kosiyana chifukwa binary logic ndi yosavuta kuyigwiritsa ntchito ndikusintha.
b) Kulamulira Kosalekeza (Kulamulira Analogi/Ntchito)
Kuwongolera kosalekeza kumaphatikizapo ma analog variables ndipo nthawi zambiri kumafuna algorithm monga PID (Proportional-Integral-Derivative). Mwachitsanzo:
- Sinthani kutentha kwa uvuni pogwiritsa ntchito chotenthetsera ndi sensa ya thermocouple.
- Yesetsani kupanikizika kwa nthunzi pogwiritsa ntchito valavu yowongolera.
- Sungani mulingo wokhazikika wa thanki poyang'anira pampu kapena valavu.
Ma PLC ambiri amakono ali kale ndi ntchito ya PID yomangidwa mkati kapena akhoza kuphatikizidwa ndi gawo lolamulira lodzipereka.
7. Kuphatikiza kwa PLC ndi HMI ndi SCADA
M'munda, ma PLC nthawi zambiri sagwira ntchito okha. Ma PLC nthawi zambiri amalumikizidwa ndi:
- HMI yowonetsera momwe makina alili, ma alarm, magawo a setpoint, ndi kuwongolera pamanja/okha. Ogwiritsa ntchito amatha kuyang'anira njira ndikuchita zinthu popanda kutsegula gulu lowongolera.
- SCADA yowunikira magawo ambiri, kupereka malipoti, kusintha kwa deta, ndikuphatikiza ndi makina opanga ambiri. SCADA imalolanso kulamulira kuchokera ku chipinda chowongolera.
Kuphatikiza kumeneku kumathandizira kuwoneka bwino kwa njira, kufulumizitsa kuthetsa mavuto, komanso kuthandizira kupanga zisankho motsogozedwa ndi deta.
8. Ubwino Wogwiritsa Ntchito PLC
Ubwino wina wa PLC pakulamulira njira ndi:
1. Yosinthasintha komanso yosavuta kusintha: Kusintha kwa mfundo kungachitike kudzera mu pulogalamuyi, popanda kufunikira kochotsa zingwe monga makina olumikizirana.
2. Yodalirika m'malo opangira mafakitale: Yopangidwa kuti izitha kupirira chisokonezo chamagetsi ndi zovuta zogwirira ntchito.
3. Kuzindikira ndi kuthetsa mavuto mwachangu: Ma PLC ambiri amapereka zizindikiro za momwe zinthu zilili, zolemba zolakwika, ndi kuyang'anira pa intaneti.
4. Kukula: I/O ikhoza kuwonjezeredwa ngati pakufunika (makamaka ma modular PLC).
5. Imathandizira kulumikizana kwakukulu: Yosavuta kuphatikiza ndi masensa anzeru, VFD, HMI, SCADA, ndi machitidwe a MES/ERP.
9. Mavuto ndi Zinthu Zoyenera Kuzisamala
Ngakhale ubwino wake, kukhazikitsa PLC kulinso ndi zovuta:
- Kapangidwe koyipa ka pulogalamu kungapangitse kuti dongosolo likhale lovuta kulisamalira. Kapangidwe ka pulogalamu, mayina a ma tag, ndi zolemba ndizofunikira kwambiri.
- Kudalira luso la ukatswiri: Kumvetsetsa magetsi, zida, ndi mapulogalamu ndikofunikira.
– Chitetezo cha pa intaneti: Ma PLC omwe ali ndi ma network ali pachiwopsezo choukiridwa. Machitidwe monga kugawa ma network, kuwongolera mwayi wopeza, ndi kasamalidwe ka ma patch akufunika kwambiri.
– Kusankha bwino zida: Kusankha molakwika mphamvu ya I/O, liwiro la scan, kapena module ya analog kungasokoneze magwiridwe antchito owongolera.
Chifukwa chake, kukonzekera dongosolo lowongolera kuyenera kuganizira zosowa za ndondomeko zomwe zikuchitika komanso zomwe zingachitike mtsogolo.
10. Zitsanzo za Ntchito za PLC mu Makampani
Kugwiritsa ntchito PLC ndikokulirapo kwambiri, mwachitsanzo:
- Makampani opanga: Kuwongolera makina a CNC, mizere yosonkhanitsira, maloboti, ndi makina onyamulira.
– Makampani ogulitsa zakudya ndi zakumwa: kupanga batchi, kusakaniza, CIP (yoyera pamalo), kuwongolera kutentha kwa pasteurization.
- Makampani opanga mankhwala: kulamulira ma valve, mapampu, ma reactor, ndi machitidwe achitetezo olumikizana.
- Kusamalira madzi: kuwongolera mapampu, ma blowers, kuchuluka kwa mankhwala, ndi kuchuluka kwa madzi osungira madzi.
- Mphamvu ndi zinthu zina zofunika: kulamulira boiler, ma compressor, ndi kugawa mphamvu.
Nthawi zambiri, ma PLC ndi mtima wa automation chifukwa amatha kuthana ndi njira zotsatizana, kuwongolera analog, komanso kulumikizana pakati pa makina papulatifomu imodzi.
Mapeto
Ma PLC akhala ukadaulo wofunikira kwambiri pakulamulira njira zamafakitale chifukwa cha kudalirika kwawo, kusinthasintha, komanso kuphatikizika mosavuta. Ndi ma PLC, makampani amatha kuyendetsa ntchito zawo zokha, kukonza kusinthasintha kwa khalidwe, kufulumizitsa kupanga, ndikupangitsa kuti kuyang'anira ndi kuthetsa mavuto kukhale kosavuta. Komabe, kupambana kwa kukhazikitsa kwa PLC sikudalira kokha pa chipangizocho chokha komanso pakupanga makina, mtundu wa mapulogalamu, zolemba, ndi njira zosamalira. Ndi kukonzekera bwino, ma PLC amatha kukhudza kwambiri magwiridwe antchito ndi kukhazikika kwa ntchito m'magawo osiyanasiyana amafakitale.
Ngati mukufuna, ndingakuthandizeni kupanga mtundu waukadaulo wa nkhani yanu (monga kukambirana zitsanzo za makwerero, kusintha kwa PID, kapangidwe ka netiweki, kapena maphunziro a milandu yowongolera kutentha) kapena kusintha kalembedwe kanu kolemba kuti kagwirizane ndi ntchito zaku koleji ndi malipoti amakampani.
