"Serial chaw nres nkoj" luv luv rau serial kev sib txuas lus interface. "Serial kev sib txuas lus" yog hais txog ib txoj kev sib txuas lus nyob rau hauv uas cov ntaub ntawv yog kis me ntsis los ntawm me ntsis nyob rau hauv ib ntus. Feem ntau cov chaw nres nkoj muaj xws li RS-232 thiab RS-485. Txawm hais tias kev sib txuas lus serial tau tsim kho qee lub sijhawm dhau los, nws tseem siv dav hauv niaj hnub no kev lag luam automation thiab tswj teb. Hauv tsab xov xwm no, peb yuav saib qhov tob ntawm RS-232 serial chaw nres nkoj. Kab lus no hais txog cov ntsiab lus hauv qab no:
1. Keeb kwm ntawm RS232
2. Lub RS232 Interface
3. Cov Khoom Siv Hluav Taws Xob hauv RS232
4. Qib -Kev hloov ICs rau RS232
5. Cov ntaub ntawv xa hauv RS232
1. Keeb kwm ntawm RS232
RS232 yog tus qauv kev sib txuas lus luam tawm los ntawm Electronic Industries Association (EIA) hauv xyoo 1962. Nws lub npe puv yog: "Standard for Electrical and Mechanical Interfaces between DTE and DCE." "DTE" stands rau "Data Terminal Equipment," xws li lub computer; "DCE" sawv cev rau "Data Circuit-terminating Equipment." Nws kuj yog qee zaum sau ua "Cov Khoom Siv Sib Txuas Lus," xws li modem. Tus "RS" hauv "RS232" sawv cev rau "Cov Qauv Pom Zoo." "232" yog tus cim. RS thaum ntxov-232 tus qauv tau tsim los ua kom muaj kev sib txuas lus ntawm cov khoos phis tawj, xov tooj programmable, thiab modems; Tom qab ntau qhov kev hloov kho, nws tau dhau los ua tus qauv kev sib txuas lus dav dav. Kev hloov kho rau RS-232 yog raws li hauv qab no:
1969 Version C (RS-232-C);
1986 Version D (RS-232-D);
Version E (RS232-E) xyoo 1991;
Version F (RS232-F) xyoo 1997;
Tam sim no, hauv kev lag luam automation, RS232 feem ntau yog siv rau kev sib txuas lus ntawm cov khoom siv xws li touchscreens, daim npav nyeem ntawv, barcode scanners, thiab tshuab luam ntawv thiab PLCs.
2. RS-232 Interface
Ua ntej F version, RS-232 siv 25-pin serial interface, uas tuaj nyob rau hauv ob hom: txiv neej thiab poj niam. Tus txiv neej connector yog siv rau DTE li, thiab tus poj niam connector yog siv rau DCE li, raws li qhia nyob rau hauv daim duab hauv qab no
Lub cev lub cev yog qhia hauv daim duab hauv qab no:
Saib cov lus hauv qab no rau tus pin txhais:
:
| Tus lej | Lub npe | Cov ntawv luv |
|---|---|---|
| 1 | Ntaub thaiv npog | |
| 2 | Cov ntaub ntawv kis tau | TxD |
| 3 | Tau txais cov ntaub ntawv | RxD |
| 4 | Thov Xa | RTS |
| 5 | Ntshiab Xa | CTS |
| 6 | DCE Ready/Data Set Ready | DSR |
| 7 | Teeb liab hauv av / kev rov qab los | SG |
| 8 | Tau txais kab teeb liab ntes | |
| 9 | Tshwj xeeb rau kev ntsuas cov ntaub ntawv | |
| 10 | Tshwj xeeb rau kev ntsuas cov ntaub ntawv | |
| 11 | Unaskos npe | |
| 12 | Secondary tau txais kab teeb liab ntes | |
| 13 | Secondary Clear Xa | (S) CTS |
| 14 | Secondary Transmitted Data | (S) TxD |
| 15 | Transmission signal elementtiming | |
| 16 | Secondary Tau txais cov ntaub ntawv | (S)RxD |
| 17 | Lub Sijhawm Txais Lub Sijhawm Lub Sijhawm (DCE) | |
| 18 | Local Loopback | |
| 19 | Secondary Thov Xa | (S) RTS |
| 20 | DTE Ready/Data Terminal Ready | DTR |
| 21 | Tej thaj chaw deb Loopback / Lub Teeb Pom Kev Zoo Detector |
|
| 22 | Ring Indicator | RI |
| 23 | Data Signal Rate Selector | |
| 24 | Transmit signal element sij hawm (DTE) | |
| 25 | Test hom |
25-pin serial chaw nres nkoj muaj ntau tus pins, ua rau nws nyuaj rau siv. Txhawm rau ua kom yooj yim rau RS232 serial chaw nres nkoj, F version txhais tau hais tias 9-pin serial chaw nres nkoj, uas kuj suav nrog ob tus txiv neej txuas (rau DTE) thiab tus poj niam txuas (rau DCE), raws li qhia hauv daim duab hauv qab no:
Saib cov lus hauv qab no rau tus pin txhais:
| Tus lej | Lub npe | Cov ntawv luv |
|---|---|---|
| 1 | Data Carrier Detect | DCD |
| 2 | Tau txais cov ntaub ntawv | RxD |
| 3 | Cov ntaub ntawv kis tau | TxD |
| 4 | Cov ntaub ntawv Terminal Npaj | DTR |
| 5 | Hauv av | GND |
| 6 | Cov Ntaub Ntawv Npaj Npaj | DSR |
| 7 | Thov Xa | RTS |
| 8 | Ntshiab Xa | CTS |
| 9 | Ring Indicator | RI |
PLC yog suav tias yog ib qho khoom siv DTE, thiab nws cov RS-232 serial chaw nres nkoj yog ib tug txiv neej connector. Piv txwv li, CM1241 RS-232 serial module rau S7-1200 muaj ib tug txiv neej serial chaw nres nkoj, raws li qhia nyob rau hauv daim duab hauv qab no:
Rau kev sib txuas lus ntawm DTE thiab DTC, kev sib txuas ncaj qha tuaj yeem siv tau, raws li qhia hauv daim duab hauv qab no:
Rau kev sib txuas lus ntawm ob DTEs (xws li PLC thiab barcode scanner), yuav tsum siv tus ntoo khaub lig- txuas. Txhua tus pins tuaj yeem txuas rau ib leeg, raws li qhia hauv daim duab hauv qab no:
Koj tuaj yeem siv txoj kev sib txuas tsawg kawg nkaus, tsuas yog siv peb lub xov hlau txuas rau TxD thiab RxD tus pins ntawm ob lub cuab yeej thiab hauv av ua ke, raws li qhia hauv daim duab hauv qab no:
Hom kev sib txuas no, uas DTE txuas ncaj qha mus rau DCE yam tsis tau dhau los ntawm DCE, tseem hu ua "null modem" kev txuas, thiab cov cable siv rau hom kev sib txuas no hu ua "null modem" cable lossis crossover cable.
3. RS-232 Hluav Taws Xob Hluav Taws Xob
Cov teeb liab hluav taws xob ntawm RS-232 xa mus thiab tau txais cov davhlau ya nyob twg yog cov cim hluav taws xob txheeb ze rau hauv av (GND). Qhov sib txawv voltage ntawm +3V thiab +15V sawv cev rau qhov laj thawj "0"; qhov sib txawv ntawm qhov sib txawv ntawm -3V thiab -15V sawv cev rau qhov laj thawj "1"; thiab qhov sib txawv ntawm qhov hluav taws xob ntawm -3V thiab +3V yog undefined. 3 V yog qhov tsawg kawg nkaus pom qhov hluav taws xob teeb liab. Hauv kev siv tswv yim, tus nqi ntawm qhov sib txawv ntawm qhov voltage yuav tsum nyob ntawm 5 V mus rau 15 V. Qhov ntawd yog, thaum xa cov ntaub ntawv, tus neeg tsav tsheb transmitter outputs ib tug zoo voltage teeb liab ntawm +5 V rau +15 V los sawv cev rau ib tug logical "0," hos ib tug tsis zoo voltage teeb liab ntawm -5 V rau -15 V sawv cev rau ib tug logical "1." Thaum tau txais cov ntaub ntawv, cov teeb liab hluav taws xob ntau dua 3 V yog suav tias yog lub teeb liab siv tau.
4. RS-232 Qib Hloov ICs
Txij li thaum microcontroller pins tso zis TTL qib, lub siab hloov pauv IC (xws li TI's MAX3232 lossis ST's ST3232 yuav tsum hloov lawv mus rau RS-232 qib. Yog xav paub ntxiv, thov mus saib kuv tsab xov xwm dhau los: Qhov txawv ntawm RS-232 thiab TTL Levels yog dab tsi? Lawv Hloov Li Cas?
5. RS-232 Cov ntaub ntawv xa tawm
Thawj lub tswv yim koom nrog hauv kev xa cov ntaub ntawv yog baud tus nqi. Raws li peb paub, serial kev sib txuas lus xa cov ntaub ntawv ib ntsis ntawm ib lub sij hawm, nrog rau chav tsev ntawm kis tau tus mob me ntsis. Yog li ntawd, tus nqi baud yog txhais raws li tus naj npawb ntawm cov khoom xa mus rau ib chav tsev ntawm lub sijhawm. Lub sijhawm lees paub thoob ntiaj teb yog qhov thib ob (s), yog li chav tsev ntawm baud tus nqi yog me ntsis / s (b / s), tseem sau ua bps (ntsis ib thib ob).
Muaj ib qho tshwj xeeb ntawm baud tus nqi (tsis yog qhov tseem ceeb); Feem ntau baud tus nqi suav nrog 9,600, 38,400, 56,000, thiab 115,200. Muaj ntau yam tseem ceeb thiab; ob tog sib txuas lus tsuas yog yuav tsum pom zoo rau tib tus nqi baud.
RS -232 yog ib qho taw qhia - rau-point kev sib txuas lus raws tu qauv. Nws cov ntaub ntawv thav duab muaj plaub ntu: qhov pib me ntsis, cov ntaub ntawv me me, qhov sib npaug me ntsis, thiab nres me ntsis.
Pib me ntsis: Ntev 1, cov ntaub ntawv tus nqi sib npaug 0, qhia qhov pib ntawm cov ntaub ntawv xa mus;
Cov ntaub ntawv me me: Ntev 8 lossis 7, sawv cev rau cov ntaub ntawv tiag tiag raug xa mus;
parity me ntsis: Ntev 0 (tsis muaj parity) los yog 1 (kawg lossis txawm parity);
Nres me ntsis: Ntev 1, 1.5, lossis 2; cov ntaub ntawv tus nqi yog ib tug logical 1, qhia qhov kawg ntawm cov ntaub ntawv ncej;
Piv txwv tias kev sib txuas lus RS232 tau teeb tsa nrog 7 cov ntaub ntawv khoom, khib sib xws, thiab 2 nres cov khoom, cov ncej thiab cov txiaj ntsig tau pom hauv daim duab hauv qab no
Tom ntej no, cia peb ua ib qho kev suav.
Piv txwv li RS-232 kev sib txuas lus teeb tsa muaj baud tus nqi ntawm 9,600, 8 cov ntaub ntawv khoom, tsis muaj qhov sib luag (0), thiab 1 nres me ntsis. Muaj pes tsawg bytes ntawm cov ntaub ntawv yuav kis tau ib ob nyob rau hauv cov kev sib txuas lus tsis?
Teb: Raws li qhov tsis muaj, qhov ntev ntawm qhov kev sib txuas lus no yog 1 + 8 + 1=10 me ntsis. Ib byte (8 ntsis) yog kis nyob rau hauv no ncej. Yog li ntawd, ntawm baud tus nqi ntawm 9600, qhov siab tshaj plaws ntawm cov ntaub ntawv tiag tiag uas tuaj yeem xa mus rau ib ob yog 9600 / 10=960 bytes.