52157788 Mang Plc Asi Slide

Chapter 2

IndustrialCommunications and

Networking

Gii thiu mt s m hnh/chun truyn tin trong cng nghip:

Chun truyn tin V24/V28 (RS-232C, RS-485 v RS-422), I2C...

Cc bus tiu biu: Profibus, CAN, Modbus, AS-I

Cc giao thc: ProfiBus, MODBUS v IEC 870-5

2.1. Khi nim v truyn tin trong mi trng cng nghip (TTCN):

Khi nim: L mng my tnh vi s nodes v phm vi a

l hn ch, thng tin trn mng l cc s o, cc trng thi v cc lnh iu khin, gn vi cc qu trnh thc, vi tin cy cao, kh nng chu nhiu tt

C kh nng kt ni vi cc mng my tnh thng thng khai thc c cc c tnh u vit v remote v database.

Topologies: Daisy chain, Ring, Bus, Star, Tree

Giao thc: (K thut ghp ni) thng dng cc giao thc cc tng pha thit b (Transport Oriented Protocols)

Bo ton thng tin trong m hnh OSI, lp 2: Phn loi li:

Li khng pht hin c Pht hin c nhng khng sa c v Pht hin v sa c

Phn tch v nh gi li: Chech sum, CRC, Parity... nh gi theo:

Xc xut xut hin, Thi gian xut hin, Theo iu kin mi trng, Theo tc ng ca i tng...

Parity: cho tng byte/character Parity kp: cho 1 packet. Tnh Parity v XOR dc

theo gi tin => pht hin li v sa li nu xc sut nh CRC: phn cng, vi mch Check sum: phn mm

Cc chun truyn thng tin: TIA/EIA (Electronics/Telecommunication

Industry Association), m hnh DTE v DCE, cc chun qui nh vt l ca tn hiu nh: Complete Interface Standards: TIA/EIA 232-F,

TIA/EIA 530-A [561]... Electrical Only Standards: EIA 422, EIA 485... Signal Quality Standards

Tn hiu: Single End, RS232 Differential, RS 422/485, MultiDrop, Hnh 201

2.2. Standard Buses:2.2.1. AS-i bus: Actuator Sensor Interface Cc (11) hng Chu u hp tc pht trin

Hnh 202. V tr AS-I bus trong h thng mng CN

2.2.1.1. Khi nim mng AS-i: AS-i (Actuator/Sensor Interface) l giao

din kt ni cc cm bin v c cu chp hnh tng thp nht (field level) trong mt h thng t ng.

2.2.1.2. Hot ng ca h thng mng AS-i: Kin trc v cc thng s hot ng ca

mng AS-i Mng AS-i l mng Single Master/ Multi

Slaves: Trong mng AS-i ch c mt master vic trao i d liu vi cc slaves trong mng, thng qua c ch polling cc slave lin tip v ch i tr li.

Topology ca mng: Mng AS-i c th c dng ng thng, hoc dng cy.

Hnh 202a. Cu trc mt mng AS-i

Hnh 203. Cu trc mng AS-i

Thi gian vng qut: AS-i Master cn 5ms trao i d liu s vi 31 nt mng - polling, analog (12 bit sensor) cn 6 vng qut - 30ms.

Tc truyn thng: Fixed 167Kbps Thnh phn nt mng: Mi nt mng c th l

cc sensor/actuator theo chun AS-i, hoc cc AS-i I/O module cho php kt ni nhiu nht vi 4 sensor/actuator nh phn

Khong cch mng: di cp truyn trong mng AS-i l khng ln, khong cch ti a 300m, vi 2 repeater max. Lng thng tin nhphn khng ln.

Ch a ch: Ch a ch thng thng, 1 Master c th

qun l 31 slaves (4I/4O), cho php kt ni vi 124 sensors/actuators.

Ch m rng (A/B), mt master c th qun l 62 slaves (4I/3O), kt ni c vi 186 actuator hoc 248 sensor.

Mi slave AS-i c gn mt a ch, lu trong EPROM ca slave . a ch c th c t do AS-i Master hoc dng mt thit b t a ch chuyn dng (mi slave ch c th c t a ch 15 ln)

C ch giao tip: AS-i hot ng kiu Master/Slave. Trong mt chu k

qut bus, Master thc hin trao i d liu vi mi slave mt ln. Master gi message 14 bit (5 bit a ch Slave v 5 bit

thng tin - d liu output hoc m gi hm), ri ch i slave tr li. Message tr li ca slave 7 bit [4 bit thng tin (d liu u vo hoc kt qu thc hin hm)]. Thi gian mt chu k bus ph thuc vo s lng

slave. Master c th gi km mt s thng bo khc. C tt

c 9 loi messge, 2 loi truyn d liu v tham s, 2 loi t a ch cho slave, 5 loi nhn dng v xc nh trng thi hot ng ca cc

slave.

Cu trc message t Master 0-CB-A4-A3-A2-A1-A0-I4-I3-I2-I1-I0-P-1 Bit 0: u Message Bit 1: cui Message CB: Bit iu khin P: Bit Parity A4-A0: Slave Addr I4 - I0:to Slave

Cu trc message ca slave: 0-S3-S2-S1-S0-P-1 Bit 0: u Mess. Bit 1: cui Mess. Bit S3-S0: to Master P: Bit Parity

K thut truyn: K thut m ho chn di tn s truyn, t ng

b theo c ch APM (Alternate Pulse Modula-tion) cho php loi nhiu => c tin cy cao.

Kim sot li: Trong 1 chu k bit 6s (chu k bus 5ms), tn hiu

trn ng truyn c receiver senses 16 ln. Theo phng php iu ch APM ni, trong mi chu k bit phi c mt hoc hai xung v cc xung k tip phi o chiu. Nh vy ch c cc tn hiu c dng ny mi c nhn v gii m, ngc li s c coi l nhiu v s b loi b.

Mi Mess. chiu di c nh, c bit u, bit cui vc khong thi gian ngh, => pht hin tn hiu sai lch. Ngoi ra, cc bit truyn cn c bit chn l parity pht hin li.

2.2.1.3. AS-i DevicesAS-i cable:

Kiu ring, kt ni vi cc thit b mng, khng cn tch v, bt vt hoc hn.

Truyn c c nng lng v s liu trn cng mt cp 2 dy.

Khng truyn c trong khong cch xa (ti a 100 mt cn c 1 repeater)

Cng c th dng bt k cp 2 dy thng thng c kch thc 2x1.5mm2 trong mng AS-i, khng cn v chng nhiu.

Repeater/Extender Repeater/ Extender: Prolongation, max 100m.

Max 300m with 2 repeatersNgun cung cp c hai u ca repeaterHai ng cp AS-i ca repeater c

cch ly v in vi Extender M rng chiu di mng thm c 100m. Ch cn ngun cung cp pha khng ni vi

Master.Cp trc tip: khng cch ly vi Extender

Power Supply Unit: Ngun cp dc c n nh, tin cy cao cho mi thit b

mng AS-i chun v cc sensor ni vo mng. Normal Actuators khng ly ngun t AS-i cable, m

thng c cp ngun ring. Addressing Device:

L thit b gn a ch v chn on (offline). Address: 1 n 31 (hoc 1A n 31A) v Ext (1B n

31B). Cc thit b mi xut xng c a ch 0. Cc Master h tr ch a ch m rng phi ni vi

cc slave c ch a ch m rng. Trn mt mng khng th c hai thit b c cng a ch.

AS-i Master: Phn sau

AS-i Gateway: AS-i Gateway (Distributed I/O) l cc thit b cho

php ni mng AS-i vi cc thit b mng khc, cng l mt Master, ng vai tr lm ch i vi mng AS-i bn di v l Slave ca mng trn (thng l PROFIBUS)

I/O Module t ti hin trng L cc module ghp ni vi cc c cu chp

hnh v cm bin nh phn, c lp t trc tip ti hin trng

Compact Module: Module kt ni vi cc c cu chp hnh v cm bin lm vic trong mi trng khc nghit

Motor Starter v load branch: Motor Starter: Thit b khi ng ng c. Mi c cu ng lc v kt ni mng AS-i u c tch hp chtrong thit b ny.

Load Branch: Thit b khi ng bng ti, c c trng bi 1 u vo, 2 u ra ni vi thit b chp hnh.

Proximity switch: Dng nhn bit, m sn phm, c dng trong

cc dy chuyn sn xut. Gm: Cm bin t: BERO inductive proximity switch Cm bin siu m: Sonar-BERO ultrasonic proximity switch.

Cm bin t v cm bin siu m c dng pht hin vt th ln vi khong cch tng i xa, nh trong mt dy chuyn ra xe t ng... Cm bin quang: Opto-BERO photoeletric proximity switch

Logic module LOGO: L thit b slave ca mng AS-i song x l c

cc php logic, cho php thc hin mt s quy trnh t ng nh, n gin.

Mt s thit b h tr nh: Push button and indicator light: B nt bm v n bo

Counter module: Module m Ground fault detection module: Module kim tra

li ni t Overvoltage protection module: Module bo v

chng qu p

Hnh 204. Siemens LOGO!

2.2.1.4. AS-i Masters:

Hnh 205. AS-I Master

Master: Thit b truyn thng AS-i nh CP243-2 (cho S7

200) v CP 342-2 (cho S7 300) Standard AS-i Master v Extended AS-i Master:

Extended AS-i Master: 62 Slave vi ch a ch m rng A/B, Standard AS-i Master ch htr c 31 slave.

Ni mng vi Extended AS-i Master phi l cc slave c ch a ch m rng, ni mng vi Standard AS-i Master phi l cc Standard Slaves.

2.2.2. Profibus:

Hnh 206. S mng Profibus

2.2.2.1. Khi nim Mng PROFIBUS:Mng PROFIBUS (Process Field Bus) l

mng truyn thng ti hin trng (cell and field area) theo chun EN 50170-1-2, DIN 19245, kt ni cc thit b vo ra phn tn (distributed I/O), cc thit b truyn ng (drives) vi cc b iu khin kh trnh, nh PC hoc SIMATIC S7.

2.2.2.2. Cc giao thc PROFIBUS: Bao gm DP, PA, FMS v FDL.

PROFIBUS DP (Decentralized Periphery) L giao din chun trao i thng tin gia

trm SIMATIC S7/M7/C7 vi cc thit b hin trng phn tn (SIMATIC ET- 200), trong cc DP Master v Slave trao i d liu vo/ra t, tc cao.

Khong cch truyn ln v tin cy cao. DP Slave: l thit b hin trng tng thch vi

cc module vo/ra c kt ni qua giao din PROFIBUS DP (CP, IM) vi b iu khin trung tm.

/v Chng trnh iu khin trung tm, cc thit b phn tn c nh a ch nh cc thit btrung tm.

PROFIBUS PA (Process Automation) IEC 61158 - 2, kt ni cc thit b vn hnh trong mi

trng khc nghit, i hi an ton d liu cao. Cho php truyn d liu v ngun cp trn cng mt ng truyn duy nht.

Topology: Star/ Line/ Tree. Tc truyn: Fixed 31.25 kbps. Mng PROFIBUS PA c kt ni vi PROFIBUS DP

qua cc b chuyn i DP/PA Coupler hay DP/PA Link, trong DP/PA Coupler ch hot ng nh protocol Converter,

Kt ni nhiu nht 5 c cu chp hnh, cn DP/PA Link hot ng nh mt slave ca mng DP.

ProFiBus FMS (Fieldbus Message Specification): L giao thc chun kiu thng ip, lng thng

tin ln, Truyn gia cc PLCs ca cc hng khc nhau,

trao i gia SIMATIC S7/M7/C7 vi PC. u im: D liu c cu trc c truyn i

mt nh dng trung lp, khng ph thuc thit btruyn (non-device specific format) v sau li c chuyn i thnh nh dng tng ng thit b nhn (device-specific format) u kia.

PROFIBUS FMS v PROFIBUS DP s dng cng mt k thut truyn v cng giao thc truy nhp bus, do c th hot ng ng thi.

PROFIBUS FDL (Fieldbus Data Link): L giao thc truyn thng vi cc thit b tng

thch cc h S5 trao i d liu vi cc mng con.

T chc mng: dng Master/Slave, Master ca mng l cc module truyn thng

DP (nh CP 342-5 - cho CPU S7 300) Topology: Star, Tree, Line Tn hiu: vi sai, RS 485 hoc Optic Thi gian x l mt vng qut 1ms vi tc

truyn l 12Mbps v 5ms vi tc truyn 1.5Mbps

Hnh 207. Profibus

Kt ni vi mng PROFIBUS DP qua cc DP/PA Coupler hoc DP/PA Link + Coupler (khi DP/PA Link l slave ca mng DP nhng l Master ca mng PA)

Mi trng truyn: Cp xon hai dy c bc (tr khng 150) Cp xon c bc + bo v trong (/v PROFIBUS

PA) cho mi trng khc nghit, IEC 61158 Cp quang: loi tr c nhiu in, tn hao

nng lng rt thp. Cp quang c ch to tcht liu nha hoc thu tinh, c th s dng in/out door, khong cch >10km

Truyn khng dy (InfraRed Technology): S liu c truyn thng qua Module ILM (Infrared Link Module) c khong cch truyn ti a l 15m.

C ch truyn: Token Bus Nu mng nhiu active nodes (masters) to thnh

mt mng Token Ring logic vi th t xc nh theo a ch ca node . Mi active node mng t nhn bit c cc active node khc. Quyn truy nhp: Token l mt frame c bit c truyn ln lt gia cc active node trong mng Token Ring. 1 node nhn c token (c gn a ch trong

token), n c th gi cc frame v ch c gitoken trong 1 khong thi gian xc nh - token holding time) c kim sot bi token timer. Khi Time Out, node mng ch c quyn gi i mt thng ip dng u tin cao.

Active node gi token c kt ni ti cc passive node trao i d liu vi slave kiu polling hoc gi d liu n slaves. Khi mt active node nhn token m khng c yu

cu trao i d liu, n chuyn token sang active node tip theo Cc passive node khng c token Cc node c th c thm vo hay loi b trong

qu trnh hot ng

Ch Master Slave Nu mng c 1 active node v nhiu passive

nodes, c gi l h thng Master/Slave. Ch truyn Master/Slave cho php Master nh a ch cho Slaves.

Master trao i d liu vi Slave kiu tun t, Master truyn xung Slave thng s cu hnh/ cc lnh trao i d liu, iu khin.

Slave gi ln cho Master trng thi, d liu thu thp c v kt qu thc hin cc lnh ca Master.

2.2.2.3. Cc dng vt l ca ProFiBus: Mng cp quang:

Hnh 208. mng cp quang ca Profibus

c im mng cp quang: Chng c nhiu in - t, Thch hp vi cc mng c khong cch truyn ln (khong cch

truyn > 10km) Cch ly (in) vi cc thit b hin trng Mng c th c cu trc dng bus, star hoc dng vng Tc truyn t 9.6Kbps ti 12Mbps

Cc thit b mng cp quang: OBT (Optical Bus Terminal) c dng kt ni cc thit b

mng hoc cc segment RS 485 khng qu 31 node vo mng cp quang. OML (Optical Link Module) cho php thit lp cu hnh mng cp

quang, c 1 giao din RS 485 v 1 hoc 2 giao din cp quang. Cc loi cp quang dng cho OBT v OLM l khc nhau, c th

l cp quang thu tinh, cp quang plastic, cp PCF FOC, glass FOC

Mng khng dy: Module ILM c s dng kt ni khng dy

cc slave ring l hoc slave segments, cho php iu khin v truyn thng vi cc thit b di ng, max 1.5Mbps, 15m. Tia hng ngoi dng truyn d liu c pht trong di +/-100 so vi trc thng.

Hnh 209. Wireless ProFiBus network

PROFIBUS PA: Tt trong mi trng CN

nh bi kim loi, n/ axit cao, p sut, tO cao...

Tc truyn c nh, 31.25Kbps

Truyn tn hiu v nng lng (ngun cp) trn cng mt cp 2 dy

Tn hiu c m hoManchester II

Hnh 210. Manchester II Code

Hnh 211. Profibus PA Network

Hnh 212. Quan h Khong cch U/I ca PA

Cc thit b mng PROFIBUS PA: Nhiu loi T/b cho cc ng dng khc nhau (w/wo Ex) Cable: nha PVC chng chy, in p trn cp khng

qu 100V. Split T Connector: kt ni thit b slave PA vo ng PROFIBUS PA chung DP/PA Link: c ghp ni vi DP/PA. Tc truyn

thng PA: 31.25Kbps, tc DP khi c DP/PA Link cth ln ti 12Mbps. 1 DP/PA Link c th ghp ni vi ti a 5 DP/PA

coupler. DP/PA coupler chuyn i format 11bit/char (Async)

=> 8bit/char (Sync) v i tc truyn. DP/PA coupler cp ngun cho cc thit b hin trng

v gii hn dng ti a trn mch. Mi trng nguy him (Ex version) dng gii hn l 90mA, trong mi trng bnh thng (non-Ex version) l 400mA.

Mng tn hiu in: RS 485: RS 485: tn hiu p vi sai, khong cch >1 km trn ng cp xon 2 dy c v bc. Cp truyn trong mng c chia thnh cc segment

c tr khng khng i. Cc thit b c ni vo mng (node mng) qua bus

terminal vi tap line hoc bus connector (thit b kt ni/gic cm) C ti a 32 node mng trn mt segment. Cc on c kt ni vi nhau bi cc repeater. C

th c ti a 9 repeater trong mt network. Cc cable terminator phi c cp ngun trc khi c kch hot. Bus connector v bus terminal c cp ngun bi thit b DTE gn vo n, cn repeater, terminator, ILM c ngun ring.

Hnh 213: S PROFIBUS - RS 485 s dng repeater

C cu trc m, linh ng vi cc bus terminal, bus connector, repeater cho php d dng gn cc thit bmng, m rng mng hay thay i cu hnh mng. ng truyn vi sai cho php cc thit b c th dng

hot ng (deactivated) m khng h lm nh hng n hot ng ca mng Lp n gin, khng cn kin thc chuyn mn su Khong cch gim, tc truyn tng ln Cn c thit b bo v chng st khi lp t ngoi tri

Cu hnh mng: Dng bus, cu trc t do, dng repeater Mi trng: Cp xon 2 dy c v bc Chiu di mng v tc : 1000m - 187.5 Kbps

400m 500 Kbps200m 1.5 Mbps100m 12 Mbps

S Repeater max: 9 S node trong mt segment max: 32

trong mt network: 127 Tc truyn: 9.6 kbps, 19.2, 45.45, 93.75, 187.5, 1.5

Mbps, 3, 6 v 12 Mbps

Mng PROFIBUS DP M hnh mng

PROFIBUS DP: PROFIBUS DP

(Distributed I/O) l giao din chun trao i d liu vo ra gia cc trm SIMATIC S7/M7/C7 vi cc thit b hin trng phn tn nh SIMATIC ET 200, trong cc DP Master v DP Slave trao i mt khi lng nh d liu vo/ra mt cch tun t vi tc cao.

Hnh 213b. Simatic ET200

Hnh 213c. Mng Profibus DP

Ghp ni PLC SIMATIC S7: Chng trnh ng dng PLC SIMATIC S7 iu khin

v kim sot qu trnh truyn thng trn mng PROFIBUS bng cc khi chng trnh FC (cho S7-300) v SFC (cho S7-400). Cc FC thc hin cc chc nng sau:

Chuyn d liu ra t vng nh ca PLC (process image, bit memory, data block) ti cc thit b hin trng

c d liu vo t thit b hin trng ti vng nh xc nh ca PLC

Thc hin cng vic gim st v chn on

Cc trm lm vic trong h PROFIBUS DP: DP Master (class 1): thit b thc hin cc tc v iu

khin DP Slaves: cc thit b hin trng, nhn lnh t

Master v gi d liu v master DP Master (class 2 tu chn): thit b lp trnh,

chun on hoc qun l

Cc dng truyn thng trong mng DP

t cu hnh Modular/ Compact DP Slaves (Trao i d liu Slave Master) Trong c ch ny, DP

Master polling ln lt cc slave, gi v nhn d liu vi slave . a ch vo/ra ca cc slave c nh t ng khi t cu hnh mng Hnh 214. Trao i d liu

DP Master Slave (a)

t cu hnh vi Intelligent DP Slave (Trao i d liu trc tip Slave Master) I-Slave l cc thit b c kh

nng thao tc c lp v t xl s liu vi cc c cu chp hnh gn vi n trc khi gi s liu v master (nh CPU S7, Drives...). Master khng trc tip truy

nhp cc I/O module gn vi I-slave, m ch truy nhp vo vng a ch ca CPU ca I-slave. Do , a ch ca cc I/O module do I-slave qun l, c t trong khi khai bo cu hnh mng cho DP I-slave.

Hnh 215. Trao i dliu ISlave Master (b)

Trao i d liu trc tip Slave > Islave Cc DP Slave c

th trao i dliu trc tip vi cc Intelligent slave vi tc cao m khng qua master.

Hnh 216. Trao i dliu Slave-Islave (c)

Trao i d liu qua 2 trm: trc tip Slave => Islave Cc intelligent slave c th c d liu t cc slave vi tc cao, c cc slave cng hay khc master vi i-slave .

Hnh 217. Direct data XCGH (d)

Trao i d liu gia 2 trm Master (Trao i d liu trc tip Slave => Master) Trong ch ny, d liu t cc slave hay i-slave c th c

master ny hay master khc trn cng mng PROFIBUS DP truy nhp. C ch ny c gi l chia s u vo v d liu c s dng

cho gia cc h thng PROFIBUS DP.

Hnh 218. Trao i s liu (e)

2.2.2.4. Hot ng ca Mng ProfibusDP MasterProfibus CPDP Master v DP Slave CPU Cycle & DP Polling Cycle

2.3. MODBUS Protocol: L Giao thc chun cho cc ng truyn mng cp

thp ( c RS232/485/422) do Modicon/ AEG/ Schneider Automation

Thng dng trong cc PLC, cc computerized sensor, cc drives, trong cc h SCADA, DCSNhiu hng dng

C cc qui c trao i lnh, d liu, diagnostics Truyn thng mc thp (232/485), gm standard

modbus v trn cc giao thc khc: TCP/IP, MAP, Master/Slave:

Master: Command (query message) Slave: Response message

Hnh 219

S Modbus

Hnh 220. Kch bn MODBUS

Device Address: gm 247 slaves, a ch 0 lBroadcast

Function code8bit data bytes, ty s lngCRC Error checkingCharacters: 7/8 bit data, PE or NonASCII/ RTU modes:

ASCII: breaking down 1 byte = 2 ASCII characters: 7, [PE/ PO], 1[2]

RTU: binary character: 8,[PE/PO], 1[2]

Hnh 221. MODBUS Format of Frames

Format of packet:

ASCII format Functions: Read

Reg, Fetch Event-log, Diagnostic, Preset Reg

RTU format: start: 4 space chr Time out: 1,5 char

time End(n)start(n+1)

Hnh 222. MODBUS Packet

2.4. IEC 870-5-101 Protocol

2.4.1. Gii thiu chung v IEC 870-5-101. Giao thc IEC 870-5 do t chc IEC (International

Electrotechnical Commission)Technical Committee 57 cho cc lnh vc telecontrol, teleprotection vtelecommunication ca cc h thng nng lng. C 5 ti liu c t v chun giao thc ny:

IEC 870-5-1 (Transmission Frame Formats) IEC 870-5-2 (Data Link Transmission Services) IEC 870-5-3 (General Structure Of Application Data) IEC 870-5-4 (Definition And Coding Of Information

Elements) IEC 870-5-5 (Basic Application Functions)

Giao thc IEC 870-5-101 cho cc ng dng c sdng cc RTU iu khin xa, cc nh ngha v c t ca giao thc ny c la chn t 5 ti liu trn.

L giao thc truyn thng gia cc thit b u cui (RTU) v h thng trung tm (Central Station).

Thng tin theo hng t thit b u cui (RTU) ti Central Station thng l cc thng s o RTU thu thp t cc thit b vt l (nh tn s, in p, dng in, cng sut) v

thng tin theo hng ngc li thng l cc lnh iu khin hot ng thit b vt l.

Mt s nh ngha:Controlling Station: Trm iu khin hot ng

ton b h thng.Controlled Station: Cc trm cp di hoc thit

b thu thp s liu RTU.Unbalanced Mode: L ch hot ng m ch

c Controlling Station khi u mt phin truyn nhn.Balanced Mode: L ch hot ng m tt c

cc trm u c th khi u mt phin truyn nhn.

2.4.2. Cu trc giao thcGiao thc a ra m hnh phn lp mng bao

gm 3 lp: Application layer Data link layer Physical layer

Application layer

Data link layer

Phisical layer

Hnh 223. IEC 780 Layers

Data TerminalEquipment

(DTE)of the

controlling station

Data circuitTerminatingEquipment

(DCE)

Data circuit TerminatingEquipment

(DCE)

Data TerminalEquipment

(DTE)of the controlled

station

Serial telecontroll

channel

Data circuit

Phisical Layer:

Hnh 224. IEC Physical Layers

Link layer:

Cung cp cc th tc truyn thng, s dng trng iu khin v trng a ch.

Lin kt gia cc trm c th c thc hin theo ch truyn thng unbalanced /balanced mode.

Nu s lin kt gia trm iu khin trung tm v cc trm khc chia s cng mt ng truyn th ch hot ng phi lunbalanced mode.

Application layer

Application Service Data Units (ASDU): lcu trc d liu trn tng ng dng.

Cc ASDU thc cht l 1 frame c cha sliu hay lnh iu khin.

2.4.3. Cc c t v truyn thng

Cc c t ny nh ngha cu hnh mng, nh dng chun k t v cc lut truyn thng.

Cu hnh mng: bao gm cc dng sau:Point - to point, figures @ next pageMultiple point - to - pointParty lineRedundant line

ControllingStation

ControlledStation

ControllingStation

ControllingStation

ControllingStation

ControlledStationControlled

StationControlled

Station

ControlledStation

ControlledStation

ControlledStation

Point - to - point Multiple point - to - point Party line Redundant line

Hnh 225. IEC Models

Hnh 2.2 Cc m hnh mng ca giao thc IEC 870-5-101

Character format: 1 Start bit, 1 Stop bit, 1 Parity bit (even) v 8 Data bits

Transmission rules: ng truyn ri l mc nh phn 1. Mi k t c mt bit khi u (binary = 0), 8 bit thng tin, mt bit

parity (chn) v mt bit stop(binary = 1). Khng c c khong thi gian ri trn ng truyn gia cc k

t trong cng mt frame. Khong thi gian xc nh li gia cc frame cho php nh nht l

33 bit (3 k t) Cc k t d liu c kt thc bi 8 bits checksum (CS).

Checksum c thc hin trn ton b cc byte mang d liu. Pha nhn thc hin kim tra: Cc bt khng mng tin/char: bit start, bit stop v parity bit. i vi mi frame: k t start, di (2 bytes trong frame c di

khng c nh), check sum ca frame v k t kt thc

2.4.4 nh dng frame d liu

Giao thc IEC 870-5-101 s dng ba nh dng frameFrame c di thay iFrame c di c nhFrame ch c mt k t

Hnh 226. IEC 780-5 Frames

Frame c di thay i: truyn d liu gia controlling v controlled station.

Frame c di c nh: dng cho cc dch v ca link layer.

Frame ch c mt k t: xc nhn cc hot ng nh ng b thi gian, yu cu dliu...

Cu trc d liuIEC 870-5-101 nh ngha: Cc Application

Service Data Unit (ASDU) cha thng tin truyn thng gia cc trm. Cc ASDU c nh ngha l cc frame d liu c di khng c nh. nh dng ca frame:Khi u frame: 1 byte START CHARACTER 2 byte FRAME LENGTH 1 byte START CHARACTER 1 byte LINK ADDRESS

Kt thc frame: 1 byte CHECKSUM 1 byte STOP CHARCTER

Hnh 226. Formats of Application Service Data Unit

Mi ASDU bao gm hai phn:DATA UNIT IDENTIFIER: 1 byte TYPE IDENTIFICATION, 1 byte VARIABLE STRUCTURE QUALIFIER, 1 hay 2 byte CAUSE OF TRANSMISSION, 1 hay 2 byte COMMON ADDRESS OF ASDU

INFORMATION OBJECT: Nu ASDU c truyn t Controlled Station theo

yu cu s liu t Controlling Station th ASDU thng tin cc i tng c th km theo th thi gian. Nu ASDU c truyn t Controlling Station th

thng tin c cha l thi gian nu l lnh ng bthi gian hay l trng thi trong lnh iu khin...

2.4.5. Command set and Scenario

Command set: Station initialisation: Khi to cc trm. Data acquisition by polling: Thu thp s liu kiu polling Cyclic data transmission: Truyn d liu c tnh chu k. Acquisition of events: Thu thp s kin. General interrogation: Th tc Controlling Station cp nht cc

Controlled Station, thc hin sau khi khi to. Clock synchronisation: ng b thi gian. Command transmission: Truyn lnh iu khin. Transmission of integrated totals: Thu thp gi tr m xung. Parameter loading: Np tham s cho Controlled Station. Test procedure: Th tc kim tra s kt ni gia cc trm. File transfer: Truyn file. Acquisition of transmission delay: Xc nh tr ng truyn.

A Case Study: Acquisition of events

Cc s kin xy ra c lu tr trong buffer ca Controlled Station cho cc s kin xy ra nhanh hn so vi tc truyn thng. Khi Controlling Station hi Controlled Station yu cu cc s kin th c hai kh nng xy ra: khng c s kin trong buffer v c s kin trong buffer ca Controlled Station. Trng hp khng c s kin trong buffer: Controlled Station tr

li NACK di dng message ch c mt k t (05H) hay hay mt frame c di c nh (fixes frame) mang thng ip "Requested data not available".

Trng hp c s kin trong buffer: Controlled Station tr li bng mt fixed frame NACK nhng bit trng thi = 1 bo hiu cho Controlling Station c s kin. Controlling gi message "Request user data class 1" yu cu v Controlled tr bng mt ASDU cha s kin, ASDU ny c th cha ton b hoc mt vi s kin ca Controlled Station.

Chapter 2IndustrialCommunications and Networking2.4. IEC 870-5-101 ProtocolPhisical Layer:Link layer:Application layer2.4.3. Cc c t v truyn thng2.4.4 nh dng frame d liu2.4.5. Command set and ScenarioA Case Study: Acquisition of events