PTZ Kontrol Dip Daiv: RS485 Bas Prinsipel, Protokol, na Komon Trabolsuting

Stori

Ogas 18, 2023

RS485 em i wanpela 'differential serial communication standard' we i yusim tupela signal lain (ol i save kolim A na B, o + na -) long salim data. Bikpela samting bilong 'differential signaling' em i strongpela 'anti-interference' inap.

RS485 Physical Layer: Em i no tupela waia tasol

RS485 em i wanpela 'differential serial communication standard' we i yusim tupela signal lain (ol i save kolim A na B, o + na -) long salim data. Bikpela samting bilong 'differential signaling' em i strongpela 'anti-interference' inap — risiva i save luksave long 'voltage' we i no wankain namel long tupela lain na i no 'absolute voltage' we i stap long graun. Dispela i min olsem nois we i save kamap long olgeta taim (olsem ol samting we i save kamap long ol 'motor' o ol 'variable frequency drive') i save pinis otomatik.

Tasol gutpela samting bilong 'differential signaling' i gat pe bilong en. RS485 bas i nidim ol stretpela 'termination resistor' (planti taim 120 ohms) i stap long tupela arere bilong bas long rausim ol signal refleksen. Sapos 'termination resistor' i no stap o ol i putim long rong posisen, ol 'signal reflections' i save kamapim ol 'data errors' - we i save kamap olsem 'signal overshoot' na 'ringing' long 'oscilloscope'. Long wok enjiniaring, wanpela 'termination resistor' we i no stap em i wanpela bikpela samting we i save mekim PTZ kontrol i no wok gut.

Pelco-D egensim Pelco-P: Protokol Chois Em i no Arbitrary

Ol PTZ kontrol protokol we ol i save yusim planti taim long sekyuriti monitoring em Pelco-D na Pelco-P. Tupela wantaim em ol 'serial communication protocols', tasol i gat ol narapela narapela data fomat: Pelco-D i yusim 7-bait fomat, na Pelco-P i yusim wanpela liklik fomat. Tupela protokol i no wankain — sapos kamera i sapotim Pelco-D na enjiniaring tul i salim Pelco-P komand, PTZ bai no inap bekim.

Samting we i givim hevi moa em olsem ol narapela narapela 'brand' i save yusim wankain 'protocol' na i gat ol liklik samting we i no wankain. Olsem, long sampela bren Pelco-D implementesen, PTZ spit enkoding i no wankain olsem standet, na dispela i mekim kontrol presisen i go daun. Insait long ol miks-bren projek, em i gutpela long sekim protokol kompatibiliti bren long bren, na noken ting olsem 'sapos olgeta i sapotim Pelco-D, ol i kompatibel.' FangService's PK69 na PK68 series i sapotim tupela Pelco-D na Pelco-P protokol, na ol i ken senisim otomatik o long han bihainim bren bilong kamera.

Ol hevi we i save kamap na rot bilong stretim hevi

PTZ kontrol feil trabelsuting i nidim wanpela sistemik ron. Oda bilong stretim hevi em: 1 sekim long 'physical layer' (sapos RS485 kebol i stap gut, sapos A/B waya i stret, sapos ol i putim 'termination resistor'); sekim 'protocol layer' (sapos kain 'protocol' i wankain, sapos 'baud rate' i wankain, sapos 'adres code' i stret); sekim ol ikwipmen (sapos PTZ yet i no wok gut, sapos pawa saplai i inap, sapos hap bilong masin i pas). Ol 'physical layer failures' em ol samting we i save kamap planti taim — A/B lain i senis em i nambawan hevi bikos long planti taim PTZ i save tanim yet, long narapela sait tasol. Taim yu wok long stretim hevi, sapos yu painim olsem PTZ i 'tanim i go long lephan' taim em i mas 'tanim i go long raithan,' pastaim sekim A/B waia. Narapela hevi we i save kamap em RS485 lain multiplexing wantaim ol 'idle wire pairs' insait long netwok kebol — sapos ol 'wire pairs' we ol i yusim long RS485 insait long kebol i gat ol 'twist rates' we i no wankain wantaim ol data pairs, dispela inap long kamapim hevi long signal. FangService's PK69 series i gat wanpela RS485 kebol tes fanksen we i stap insait long en we inap long luksave long kebol i go het yet, ol sotpela seket, na ol 'crossover'. Sapos yu bungim wantaim 'protocol analysis function', em inap long painim hariap 'failure layer'.

RS485 Netwok Topoloji na Distens Limit

RS485 bas topoloji na mak bilong longwe em ol samting we ol i save lusim tingting long en long taim bilong enjiniaring disain. RS485 standet i rekomendim wanpela 'bus-type topology' - olgeta divais i stap wankain long wanpela bikpela lain, wantaim wanpela 'termination resistor' long tupela arere bilong bikpela lain. Wanpela 'star topology' (olgeta divais i konektim long wanpela sentral poin) i save kamapim ol 'signal reflections', we inap long kamapim 'communication failure' maski ol i stap longwe tru.

Maksimum RS485 komunikesen distens em i inves proporsenel long 'baud rate'. Long liklik 'baud rate' bilong 9600bps, mak bilong en inap long kamap 1200 mita; long bikpela 'baud rate' bilong 115200bps, mak bilong en i no save winim 200 mita. Sapos ol PTZ divais insait long wanpela projek i stap longwe, tingim long putim ol 'repeater' o daunim 'baud rate'. FangService's PK69 na PK68 series, long RS485 tes mod, i ken soim ol 'current communication parameters' (baud rate, data bits, stop bits, parity), na dispela i helpim ol enjinia long sekim hariap olsem konfiguresen i stret.

Stat long RS485 i go long IP PTZ Kontrol: Kamap bilong Komyunikesen Teknoloji

Ol i save yusim PTZ kontrol long rot bilong RS485 serial bus, tasol taim ol IP kamera i kamap planti, PTZ kontrol i wok long senis i go long ol IP netwok-bes rot. Moden IP PTZ i ken kisim ol kontrol komand stret long netwok kebol long rot bilong ONVIF protokol o ol protokol bilong ol vendor, na dispela i pinisim nid bilong indipenden RS485 kebol.

Tasol RS485 bai no inap lus klostu taim. Insait long ol 'coaxial HD' sistem (AHD/TVI/CVI), PTZ kontrol i save dipen yet long RS485; long planti ol tradisenel sistem we ol i putim pinis, RS485 em i wanpela rot tasol bilong bosim. Olsem na, maski long taim bilong IP, RS485 PTZ kontrol i stap yet olsem wanpela bikpela skil bilong ol sekyuriti enjinia. FangService's netwok tes instramen lain i karamapim tupela RS485 PTZ kontrol tes (PK68/PK69 series) na IP netwok tes (PK69 series), na i givim ol gutpela tes solusen bilong tupela tradisenel na moden sistem. Long ol miks projek we i gat ol nupela na olpela sistem, dispela 'dual-coverage' inap em i gutpela tru. View the Network Test Instruments Collection