ut 2023
RS485 dafay jëfandikoo ñaari ligne siñaal (ñu koy faral di woowe A ak B, wala + ak -) ngir yónnee ay done. Njariñ li gëna mag ci siñaale differensiyel mooy mën nañu baña jaxasoo.
RS485 dafay jëfandikoo ñaari ligne siñaal (ñu koy faral di woowe A ak B, wala + ak -) ngir yónnee ay done. Njariñ li gëna mag ci siñaale differensiyel mooy kàttan gu dëgër giy tere interference - ki koy jot dafay gis wuute voltage bi am ci diggante ñaari ligne yi moo gën voltage absolu bi méngoo ak suuf si. Loolu dafay tekki ni bruit biy bawoo ci mode common (lu melni interference yu bawoo ci motëri jege yi wala dawalkat yu am fréquence yu bari) dañuy fomm ci saasi.
Waaye njariñu siñaale différentiel mingi ànd ak njëg. Bus RS485 defay laaj ay resistor yu jub (120 ohms) yuñ samp ci ñaari catu bus bi ngir dindi reflection siñaal yi. Sudee resistor biy jeexal amul wala ñu samp ko ci barab bu jaarul yoon, reflection siñaal yi dañuy waral njuumte ci done yi — ñuy wane ni siñaal bi dafa ëpp ba noppi di sone ci oscilloscope bi. Ci wàllu xam-xam, résistance bu ñàkk ci njeexte gi mooy sabab bi gëna bari luy waral PTZ di ñàkka mëna doxal.
Protocolu PTZ yiñ gëna jëfandikoo ngir saytu kaaraange mooy Pelco-D ak Pelco-P. Ñoom ñaar ñépp ay protokolu jokkoo lañu, waaye ak formaa done yu wuute: Pelco-D dafay jëfandikoo formaa 7-byte, waaye Pelco-P dafay jëfandikoo formaa bu gëna ndaw. Ñaari protokol yi mënul ànd - sudee kameraa bi dafay jàppale Pelco-D te jumtukaayu ingenieur bi dafay yónnee komand Pelco-P, PTZ du tontu.
Li gëna indi jafe-jafe mooy ni màrk yu wuute yi di jëfandikoo benn protokol bi mën nañu am ay wuute yu ndaw. Ci misaal, ci yenn màrk yu Pelco-D amal, encodage gaawaayu PTZ wuute na ak standard bi, moo waral ñu wàññi njubte gi ci doxal. Ci projet yu am màrk yu wuute, dañu leen di digal ngeen xool ndax màrk bu nekk mën na ànd ak màrk, moo gën ñuy xalaat ni 'sudee ñoom ñépp dañu jàppale Pelco-D, kon mën nañu ànd.' FangService's PK69 ak PK68 dañuy jàppale protokol Pelco-D ak Pelco-P, te mën nañu soppi ci saasi wala ci loxo lépp di aju ci màrku kamera bi.
PTZ seytu jafe-jafe saafara jafe-jafe sistemik. Li ñuy digal ñu def ngir saafara jafe-jafe yi mooy: 1 saytu couche physique (ndax fiil RS485 bi amul benn sikk, ndax kablaas A/B yi jub nañu, ndax resistor biy jeexal dañu ko samp); xool layer protocole (ndax xeetu protocole bi méngoo, ndax baud rate bi méngoo, ndax kodu adres bi jub na); Saytu couche ekipmaa (ndax PTZ bi ci boppam defa defoon, ndax kuuraŋ bi doyna, ndax wàll mekanik bi dafa jaxasoo). Faatu couche physique mooy gëna bari - A / B line reversal mooy jafe-jafe bi gëna insidious ndax ci anam yu bari PTZ baa ngi wëréelu, ci yoon wi. Sooy debug, soo gisee ni PTZ dafay 'weer ci cammoy' fekk dafa wara 'weer ci ndeyjoor,' xoolal bu njëkk A / B wiring. Meneen jafe-jafe bu bari mooy RS485 ligne multiplexing ak ñaari fiil inactif ci fiil reso bi - sudee ñaari fiil yi ñuy jëfandikoo ngir RS485 ci fiil bi am tax yu wuute ak ñaari done yi, siñaal bi mën na indi interference. FangService's PK69 dafa am fonction test RS485 buñ tabax ci biir bu mëna gis fiil bi wéy, sircuit yu gàtt yi ak crossover yi. Buñu ko boole ak fonction analyse protocole bi, mën na gaaw gis couche de failure bi.
Topologie bus RS485 ak yamaleg distance ay jafe-jafe lañu yu yomb di xàddi ci jëmmal ingenieur. Standard RS485 dafay digal topologie bu nuru bus - bépp aparey paralel ci benn ligne bu mag, ak benn resistor buy jeexal ci bu nekk ci catu ligne bu mag bi. Topologie star (aparey yépp ñu boole seen bopp ci benn poñ bu mag) dafay waral siñaal bi di feeñ, te loolu mën na tax jokkoo bi dakkal doonte fu soriwul noonu.
Distance bi gëna mag ci jokkoo RS485 mingi méngoo bu baax ak viteesu baud bi. Soo amee baud bu woyof ba 9600bps, distance bi gëna mag mën na yegg ba 1200 meetar; ak viteesu baud bu yéeg ba 115200bps, diggante bi gëna mag du ëpp 200 meetar. Sudee aparey PTZ yi ci benn projet dañu leen séddale fu sori, xalaatal yokk ay repeater wala wàññi baud rate. FangService's PK69 ak PK68, ci anam test RS485, mën nañu wane parametru jokkoo bi fi nekk (baud rate, bit done, bit arrêt, parité), di jàppale insiñër yi ñu gaaw xool ndax tabb gi jub na.
Kontrol PTZ bu yàgg bi ñu ngi koy amal jaaraleko ci bus serial RS485, waaye ginaaw bi kamera IP yi di gëna bari, kontre PTZ dafay jëm kanam ci jëfandikoo reso IP. IP PTZ bu bees bi mën na jot komand yi ci fiil reso bi jaaraleko ci protokol ONVIF wala protokol jaaykat bi, moo tax doo soxla fiil RS485 bu moom boppam.
Waaye RS485 du gaawa jeex. Ci sistem HD coaxial (AHD/TVI/CVI), PTZ dafay wéy di aju ci RS485; ci sistem yu bari yuñ jota samp, RS485 rek mooy anam wi ñuy doxalee. Kon, ba ci jamonoy IP, RS485 PTZ dafay wéy di nekk xam-xam bu am solo ci ingenieur yiy saytu kaaraange. FangService's lignée jumtukaayi test reso dafay muur test RS485 PTZ (PK68/PK69 series) ak test reso IP (PK69 series), di joxe test yu mat sëkk ngir sistem yu yàgg yi ak yu bees yi. Ngir projet yu wuute yu amaale sistem yu bees ak yu yàgg, mën mën bi am ñaari coverage lu am solo la. View the Network Test Instruments Collection
Waxñu senaario projet bi ak li ngay laaj, dina ñu la jox pexe mi gën, nu jox la devis bi ci diiru 24 waxtu.
Wutal devis bu amul faydaPK66 portable engineering tool, PK67 wristband engineering tool, PK68 professional video tester, PK69 full-featured network engineering tool — four series covering the complete needs from basic video testing to advanced PoE analysis. Supporting IPC/AHD/TVI/CVI multi-format coaxial HD, RS485 PTZ control, and PoE power testing, designed for installation, debugging, and maintenance of security monitoring systems.
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