Nei 4-20mA?

Chii chinonzi 4-20mA?

Iyo 4-20mA DC (1-5V DC) chiratidzo chiyero chinotsanangurwa neInternational Electrotechnical Commission (IEC) uye inoshandiswa kune analog masaini muma process control system.

Kazhinji, chiratidzo chezvino chezviridzwa nemamita chakaiswa ku4-20mA, ine 4mA inomiririra hushoma hwazvino uye 20mA inomiririra yakanyanya ikozvino.

Sei kubuda ikozvino?

Mumaindasitiri magadzirirwo, kushandisa siginecha amplifier kune mamiriro uye kufambisa masaini madaro marefu uchishandisa masaini emagetsi kunogona kutungamira kune akati wandei nyaya.Chekutanga, masaini emagetsi anofambiswa pamusoro petambo anogona kutapukirwa nekukanganiswa kweruzha.Chechipiri, kushorwa kwakagoverwa kwemitsara yekufambisa kunogona kukonzera kudonha kwemagetsi.Chechitatu, kupa simba kune iyo chiratidzo amplifier mumunda kunogona kuve kwakaoma.

Kugadzirisa nyaya idzi uye kuderedza kukanganiswa kweruzha, yazvino inoshandiswa kufambisa masaini nekuti hainyanyi kunzwa ruzha.Iyo 4-20mA ikozvino loop inoshandisa 4mA kumiririra zero siginecha uye 20mA kumiririra yakazara-chiyero chiratidzo, ine masaini ari pasi pe4mA uye pamusoro pe20mA anoshandiswa kune akasiyana maalarm.

Sei tichishandisa 4-20mA DC (1-5V DC)?

Zviridzwa zvemumunda zvinogona kuita maviri-waya sisitimu, uko magetsi uye mutoro zvakabatanidzwa munhevedzano neyakajairwa poindi, uye waya mbiri chete dzinoshandiswa pakutaurirana kwechiratidzo uye kugovera magetsi pakati penzvimbo inotapurirana nekamuri yekudzora chiridzwa.Kushandisa 4mA DC siginecha seyekutanga ikozvino inopa static inoshanda ikozvino kune transmitter, uye kuseta yemagetsi zero point pa4mA DC, isingaenderane neye mechaniki zero point, inobvumira kuonekwa kwekukanganisa kwakadai sekurasikirwa kwemagetsi uye kutyora kwetambo. .Pamusoro pezvo, iyo mbiri-waya system yakakodzera kushandisa zvipingamupinyi zvekuchengetedza, kubatsira mukudzivirira kuputika.

Zvishandiso zvemukamuri yekudzora zvinoshandisa voltage-parallel chiratidzo chekufambisa, uko zviridzwa zveiyo imwechete yekutonga system inogovera yakajairwa terminal, zvichiita kuti zvive nyore kuyedza chiridzwa, kugadzirisa, komputa interface, uye alarm zvishandiso.

Chikonzero chekushandisa 4-20mA DC yekutaurirana kwemasaini pakati pezviridzwa zvemumunda uye yekudzora kamuri zviridzwa ndechekuti chinhambwe pakati pemunda nekamuri yekudzora chinogona kuve chakakosha, zvichitungamira kune yakakwira tambo kuramba.Kuendesa masaini emagetsi pamadaro marefu kunogona kukonzera kukanganisa kwakakura nekuda kwekudonha kwevoltage kunokonzerwa nekupokana kwetambo uye kuramba kwekuisa kwechiridzwa chinogamuchira.Kushandisa inogara iripo sosi siginecha yekutapurirana kure inovimbisa kuti ikozvino muchiuno inoramba isina kuchinjika zvisinei nehurefu hwetambo, ichivimbisa kutapurirana chaiko.

Chikonzero chekushandisa 1-5V DC siginecha yekubatanidza pakati pekamuri yekudzora zviridzwa ndeye kufambisa zviridzwa zvakawanda zvinogashira chiratidzo chimwe chete uye kubatsira mukuita wiring uye kugadzira akasiyana akaomarara ekudzora masisitimu.Kana kwazvino sosi ichishandiswa sechiratidzo chekubatanidza, kana zviridzwa zvakawanda zvichigamuchira chiratidzo chimwe chete panguva imwe chete, kupikisa kwavo kwekupinza kunofanirwa kubatanidzwa munhevedzano.Izvi zvaizopfuura huwandu hwekuremerwa kwechiridzwa chekufambisa, uye chiratidzo chepasi chingave chezviridzwa zvinogashira zvingave zvakasiyana, kuunza kupindira uye kudzivirira pakati pepakati magetsi.

Kushandisa chiratidzo chemagetsi chekubatanidza kunoda kushandura chiratidzo chazvino chinoshandiswa kutaurirana nezviridzwa zvemumunda kuita chiratidzo chemagetsi.Iyo yakapusa nzira ndeyekubatanidza yakajairwa 250-ohm resistor munhevedzano mune yazvino yekufambisa wedunhu, kushandura 4-20mA DC kuenda ku1-5V DC.Kazhinji, basa iri rinoitwa neanotumira.

Iyi dhizaini inoshandisa 250-ohm resistor kushandura 4-20mA ikozvino chiratidzo kuita 1-5V voltage chiratidzo, uyezve inoshandisa RC sefa uye diode yakabatana neiyo microcontroller's AD yekutendeuka pini.

"Pano yakanamatira dhiyabhorosi yakapfava yekushandura 4-20mA yazvino chiratidzo kuita chiratidzo chemagetsi:

Nei iyo transmitter ichisarudzwa kushandisa 4-20mA DC chiratidzo chekufambisa?

1. Mafungiro ekuchengetedza nzvimbo dzine njodzi: Kuchengeteka munzvimbo dzine njodzi, kunyanya pazviridzwa zvisingaputika, zvinoda kuderedza kushandiswa kwesimba uye kusimba kunodiwa kuchengetedza chiridzwa chichishanda.Matransmitters anoburitsa 4-20mA DC yakajairika siginecha anowanzo shandisa 24V DC magetsi.Kushandiswa kweDC voltage kunonyanya nekuti inobvisa kudiwa kwehombe capacitor uye inductors uye inotarisa pane yakagoverwa capacitance uye inductance yekubatanidza waya pakati peiyo transmitter uye control room chiridzwa, iyo yakadzikira zvakanyanya pane yekubatidza ikozvino yehydrogen gasi.

2. Yazvino sosi yekufambisa inosarudzwa pamusoro pemagetsi sosi: Muzviitiko apo chinhambwe chiri pakati pemunda nekamuri yekudzora chakawandisa, kushandiswa kwemagetsi emagetsi masaini ekufambisa kunogona kuunza zvikanganiso zvakakura nekuda kwekudonha kwemagetsi kunokonzerwa nekupokana kwetambo uye kupinza. kushorwa kwechiridzwa chekugamuchira.Kushandisa yazvino sosi siginecha yekutapurirana kure inovimbisa kuti ikozvino muchiuno inoramba iripo, zvisinei nehurefu hwetambo, nekudaro kuchengetedza kutapurirana chaiko.

3. Sarudzo ye20mA seyakanyanya ikozvino: Kusarudzwa kwehuwandu hwemazuva ano hwe20mA hunobva pakufunga nezvekuchengeteka, kushanda, kushandiswa kwesimba, uye mari.Zviridzwa zvinoputika zvinogona kungoshandisa low voltage uye yakaderera ikozvino.Iyo 4-20mA ikozvino uye 24V DC yakachengeteka kuti ishandiswe pamberi pemagasi anopisa.Iyo yekubatidza ikozvino yehydrogen gasi ine 24V DC ndeye 200mA, yakakwira zvakanyanya kupfuura 20mA.Pamusoro pezvo, zvinhu zvakaita senge chinhambwe pakati pezviridzwa zvesaiti yekugadzira, mutoro, mashandisirwo emagetsi, zvinodiwa zvemagetsi chikamu, uye magetsi ekupa zvinodiwa zvinotariswa.

4. Sarudzo ye4mA seyokutanga ikozvino: Mazhinji ma transmitters ayo anobuda 4-20mA anoshanda mune maviri-waya system, uko magetsi uye mutoro zvakabatanidzwa munhevedzano nenzvimbo yakajairika, uye waya mbiri chete dzinoshandiswa pakutaurirana kwechiratidzo. uye simba rekupa pakati pemunda wekutumira uye chekudzora kamuri chiridzwa.Sarudzo ye4mA yekutanga ikozvino yakakosha kuti transmitter dunhu rishande.Iyo 4mA yekutanga ikozvino, isingaenderane neyemakanika zero point, inopa "inoshingaira zero point" inobatsira kuona zvikanganiso sekurasikirwa kwemagetsi uye kutyora kwetambo.

Iko kushandiswa kwe4-20mA masiginecha kunovimbisa kupindira kushoma, kuchengetedzeka, uye kuvimbika, zvichiita kuti ive chiyero chinogamuchirwa zvakanyanya mumaindasitiri ekushandisa.Nekudaro, mamwe mafomati emasaini ekubuda, akadai se3.33mV/V, 2mV/V, 0-5V, uye 0-10V, anoshandiswawo kubata zvirinani masaini masaini uye kutsigira akasiyana siyana ekudzora masisitimu.