Nghiên cứu ứng dụng realtime linux trong hệ điều hành linux cho điều khiển tự động hóa các quá trình

De giai thich ve khuynh huang nay mot chuyen gia d5 nhan dinh : "COng nghe ngay Gang phat trien, yeu ceu veyi he thong di& khien ngay cang cao, se khOng con xa la khi mot nha may co the

UY BAN NHAN DAN TP.HCM CONG HOA XA HOI CHU NGHIA VIET NAM SO' KHOA HOC VA CONG NGHE Diic lap - Ty' do - Hanh phuo

BAO CAO NGHIEM THU DE TAI NGHIEN CCM KHOA HOC VA PHAT TRIEN CONG NGHE

Ten cue tai

NOlien dm -angdung realtime trong he diL hanh Linux cho dieu khien tix diOng cac qua trinh

ChU nhi"Orn cue tai: Nguyen Xuan Hoang

quan cht:i tri: Vien nghien cCpu va phat

trien cong ngh'e' mai

05-2006

UY BAN NHAN DAN TP.HCM CONG HOA XA HOI CHU NGHTA VIET NAM SO' KHOA HOC VA CONG NGHE D'Oc lap - Ty, do - Hanh phiic

BAO CAO NGHIEM THU DE TAI NGHIEN COU KHOA HOC VA PHAT TRIEN CONG NGHE

Thu(lc htarng: dOng hoa

Ten c16' tai Nghien ciru u•ng dung realtime trong he dieu hanh Linux cho diL khi6n tu• Qng cac qua trinh

Ch6 nhiOm cue tai: Nguy6n Xuan Hoang quan cht:, tri: Vin nghien alpu va phat

trien cong ngh0 mai

L en NOI DAU

Toi xin duvc b5t dAu bAng mot not dung thao luan tren tap chi Thiet ke Ira Dieu khien (CONTROL DESIGN magazine), dO la "co phai thol dal cua Linux trong dieu khien fix dOng hoa da den?" (Is time for Linux yet?)

Di nhien la chu'a the co mot cau tra lai co va khOng mot cach r6 rang,, m0t s6 quan

diem thi cho rang Linux van chua san sang, mot so lac quan thi lai cho rang can song than "Linux" da bat dau d6 b0 vao linh vtyc cong nghiep d6ng hoa veri,cac tieu chi& rat khat khe nay Tuy nhien neu nhin vao cac th6ng tin tren internet bang cach

g6 vao tir kh6a tim kiern "PLC Linux" thi chCing ta CO the thay so luvng cac nh6m

nghien ciru phat trien, cac di,P an ma nguOn ma va cac cong ty da phat then va dang ban cac san pharn tax d6ng hoa sir Ong Linux 115 tang mot cach clang ke so vai theyi diem cach day mot nam khi chCing toi bat dau nghien ciru de tai nay De giai thich ve khuynh huang nay mot chuyen gia d5 nhan dinh :

"COng nghe ngay Gang phat trien, yeu ceu veyi he thong di& khien ngay cang cao, se khOng con xa la khi mot nha may co the crvac yen hanh mot cach hOan tOan tir Ong

va ducyc kiem s6at qua internet vai cac ket n6i kh6ng day chOng ta se nhanh chOng they xuet hien tren thi twang cac he th6ng dieu khien toc do cao; On crinh (redundant)

va de mo' rOng (scability), kha nang ket not va lien lac (la dang va gia thanh ngay Gang

He dieu hanh ma ngu6n ma Linux vai kha nang chay tier) nhieu loai vi X CP 1)% 8/16 bit, DSP cho tai cac IBM mainframe, kha nang ket n6i mang cia dang, clap (mg thai gian thyv, cong vai mot cong citing ciOng ciao cac lap trinh vien, 1(2 thuet vien va cac nha nghien ciru se la clOng Arc manh me de thay clOi dien mao caa nganh clOng h6a

ma nhuchang ta clang thay hien nay'

MUC LUC

1 Cac qui mfYc

De de dang cho viec tham khao tai lieu, dual day la m6 to cac tCY kh6a thtyoing duvc dung :

PC104 : Board mach CPU 486DX nhOng theo chuan PC104

Realtime Linux: h0 (lieu hanh Linux vai tinh nang ma rOng cho phep

chay cac tang dgng thol gian thtyc

Module I/O: cac module giao tip I/O

Wifi: mang lien lac kh6ng day

PC: may tinh

PLC: WO dieu khien lap trinh logic (programable logic controller)

Linux PLC: la san pham cua dty an bao Om board PC104 chay he dieu

hanh linux thol gian thyc va cac module I/O

WCT: thol gian tre cua h0 thong trong truVng hgp xau nhat

BUS: mang truy'en du, lieu

HMI (human-machine interface): giao tip ngty6i va may

2 Gidei thiOu tong quan

Khai niem PLC &vac phat then Ur nhCvng nam 1960 de thay the cac mach relay duvc sir dung rat phi bien trong cac may di& khien congCu Ngirai lap trinh dung PLC de dinh nghia mot loat cac thao tac may diet., khien, PLC se lam viec bang cach doc cac tin hieu dau vao tip thiet bi nhu' cam 'Dien, hay cong tac hanh trinh va Oa tren cac gia tri do de dOng hay ngat thiet bi dau ra

6' clang dan gi5n nh5t thi PLC co nhiem vu thay the cac relay, thay vi mot may

ca khi vai cac relay va cac IDO dinh thai duvc ket not de di6u khien hoat dOng cua may, thi PLC la mot Nip den dun gian lam cac chin Wang twang tty, va bevi

vi kh5 nang lap trinh bang ng6n ngir may tinh nen de thay ai han nhieu so vai

he th6ng relay vat 19, ngoai ra PLC con cO s kha nang thkrc hien cac phep tinh toan so hoc va cac hoat Ong khac nhu'dieu khien servo va do cac th6ng so analog

Tuy nhion theo thai gian cong nghe PLC da phat then manh me, kha

the

va anh hu,ang cua no kh6ng chi giai han 0' M VC tieu ban dau la thay the cac he thong relay Val cac the he PLC hien nay, chimg to CO the xay dkrng cac he thong dieu khien theo cac giai thuat neural, adaptive control phivc tap, thai gian dap Ong co the dat den vai micro giay: Ngivai sir dung c6 the theo dOi mot cach try,c quan hoat Ong dm he thOng dieu khien qua cac giao dien HMI va Web DOi vai rival lap trinh PLC thi cong viec tra nen de clang han vai cac cong Cy lap trinh trtyc quan theo clang LADDER, IEC-61131 A neu muon ca the dung cac ng6n ngir cap cao nhu' C, Basic Nhu'ng sty tien hoa van chu'a dung lai, cong vai sty tham gia cua he dieu hanh Linux, vai sty ra dai dm cac thiet ke ph5n cirng mai, mot dat song cong nghe mai lai bat clAu Co the tom tat cac huang phat trien chinh trong viec phat then cac he thong PLC mai dual clay:

D Cai thien tic dO dap irng thai ‘ gian thkrc (realtime improvement): thai gian clap ivng la ket qua dm sty ket hap giCfa phan cirng va ph5n mem Song song vai sty ra dai dm cac IDO vi xir 19 vai tic d6 ngay cang cao hurl, cac kien truc phivc tap han nhu' cac vi x0, 19 lai giCva ARM + DSP, MIP + DSP,

he da xiv 19 thi cac he dieu hanh cung ph5i lien tuc thay d6i, nhCvng gi5i thuat dinh thai (scheduling) mai, nhuing m6 hinh dap ivng lu,61 (Grid) cho phep he th6ng clap ivng nhanh va On dinh (redundant)

➢ Phat then cac giao tiep phAn cirng va driver cho cac module PLC: tinh Wang

de cal dat, de ma Ring va thay nOng (hot-swap), to clOng cau hinh va to chuAn dOan (self diagnostic) la, yeu cau ca ban trong cac he th6ng PLC Ng6ai ra de dap Ong cac you cat khac trong cac Ong dung khac nhau thi cac mo hinh bus mai duvc phat then nhu' PCI-express, CAN 2.0, LIN Bus Sy tuang thich giipa cac module dieu khien dm cac hang phat then khac nhau (nhu' giCra Siemens va AB) cung cluac dat ra

fr Cac Gong cu phat then: cac cong cu lap trinh trkic quan han,d6 clang hen, cho phep ngudi lap trinh mO phong he thong trirac khi chay ten he thong thu,c su', tinh kha chuyen (portibility — cho phep mot chuang trinh chay ten cac he th6ng khac nhau) cung la mot tinh nang dang duvc nghien Ngoai ra cac giai thuat dieu khien mai duvc b6 xung lien tuc diyai dang cac thu, vien u'ng dung

fr Cac img dung tuung tac ngiyai may (HMI — Human Machine Interface): cac Gong cu thiet ke cho phep nhanh chong tao ra cac giao dien d6 hoa, cho phep theo d6i hoat dOng dia he thong dieu khien theo cac thong s6 thai gian thcrc dud' dang tru'c quan Cac tinh nang thu th'ap du, lieu (SCADA), dieu khien tiy xa qua internet cung dang duvc phat then

2.1 Tinh hinh nghien Cl:FU ngOai nutec

CO rot nhieu cac vien nghien ciru, car-19 nhu' cac cong ty ten the giai dang tap trung phat then cac he th6ng dieu khien sCr dung Linux; Nhieu san pham van can a trong phong thi nghiem va cung co nhieu san pham da thanh cong ten thi truang Dual day la mot s6 thOng tin:

• Honeywell dua Linux vao he th6ng dOng hOa trong building: theo SYSGO mot cong ty phhn mem a chau au \Ara cong b6 hoan thanh he thOng dieu khien trong Building cho Honeywell ten nen Linux San phan du' kien se du,a ra thi twang vao dOu nam 2004 De biet them thOng tin ye chi tiet ve

san pham co the tham khao website dual day

http://linuxdevices.com/news/NS8512023233.html

• Module dieu khien PLC cCia hang Kontron: day la thiet bi tuang d61 hoan chinh du'ac ding b6 vao 10/2005 veil cac tinh nang co nhieu diem tuang dOng vai muc tieu aim de tai He th6ng bao g6m mot module dieu khien dung b6 vi X1.1' lcf Geode 1200SC, va chay he dieu hanh Linux, cac module I/O theo chuen FieldBus

Xem http://www.linuxdevices.com/articles/AT8507873630.html de biet them chi tiet

Hinh 2 Module ThinklO cda hang Kontron

SCADA IAD3 ERP WNW bik Ira

MIL/Begolloh

t

=FL= Nuersetest

PROR BUS, DeviceRot, 111%

Hinh 3 So' d6 ket n6i c,ac module cua hang Kontron

• Module dieu khien cong nghiep co }(6t not mang sir dung Linux: xem

website dual Clay 86 biet them thong tin

http://www.linuxdevices.com/news/NS5147390086.html

• Robot di6u khien bang he dieu hanh Linux: xem website dual day de biet

them thong tin

http://www.linuxdevices.com/articles/AT2717739661.html

http://www.linuxdevices.com/news/NS2044443521.html

• Module dieu khien six dung Linux iing dung trong automation: xem website

clued day 86 biet them thong tin

http://www.linuxdevices.com/news/NS2629019236.html

2.2 'Tinh hinh nghien CiPU trong nutec

Hien tai trong nuac con dang bo ngo linh V1,FC nay, mac du co mot sO vion

nghien cu'u hay truang dai hoc co nhCing 86 tai ve phat trien he thOng nhOng

cho robot, hay he th6ng thu thep s6 lieu (sir dung Windows hay DOS), tuy

nhien cac de tai nay chi diyng a linh vuic hoc thuet chua phu hop cho viec ap

dung trong moi twang cong nghiep thkyc to

3 Tom tat ket qu6 de tai

DOn dau xu the phat then dm ding nohe, myc tieu cua de tai la nhArn phat trien m6t san phem vai chi phi phat then phhn mem va phhn arng khong qua cao, phi) hgp cong nghe the tpo tpi Viet Nam, nhArn dap Ong m6t phan (loan thi trueyng trong rinh vvc tv d6'ng h6a ma cy the 16 link vvc can dinh luvng (Batching Automation)

Dva ten nhOng you ceu ye dap Crng he thong, yeu ceu ye tuang tac ngvgi va may (HMI) He dieu hanh Linux la chon Iva va dike' day la ceu hinh he thong cua san phAm

3.1 Kik trim hg thOng

He thong duvc m6 to nhu' trong Hinh 4, bao gam m6t board mach PC104- 486DX (PC104) chpy he dieu hanh nhung Linux thoi gian thvc (realtime

embedded Linux) va cac module I/O nhu' module Digital, Loadcell Board PC104 va cac module duvc ket not qua he thong bus chung 5 day (xem dinh nghia Bus he thong) He thong co the ket not v6i may tinh va cac thiet bi dieu khien khac qua he thong mang Ethernet hoc mpg khOng day Wifi

3.2 Bang m6 to th6ng s6 ky thuat cua h0 thOng

Bang dual day ma to tom tat thOng so k9 thu'Ot cua cac module trong he thong:

64MB DRAM 8MB Disk On Chip

1 port RS232,1 port RS485, 1 port Ethernet

/ 4 Out, 8 Out, 8 In)

Board Supply Power: 7V — 24V

Resolution: 13bit Sample rate: 100 sps

Bang tom tat cac module phan mem duvc xay dtyng trong he thong:

1 • HO dieu hanh Linux

thoi gian thtyc

• Cac driver cho I/O

module

• Thu, vien chtyang

trinh xay dyng giao dien HMI

• Cac share library va

init tool

4MB Flash 16MB SDRAM Thai gian bootup la

15s

Chuang trinh chay tren board mach PC104

• He thong co

65535 mirc dO

TOc dO dap C.png tong the cua he thOng diya tren t6c do dap tYng cua board mach I/O la 2ms

IN tien

• D6 u,ii tien dun bac

• Co realtime fifo cho phep trao

ai do' lieu realtime

3 Giao din graphic engine

va chiyung trinh HMI

T6an b6 phan chuung trinh nam gon trong 8MB Flash va 16MB SDRAM

4 MO t6 chi tiet he thOng

4.1 BUS he thong (Common Bus)

Module PC - 104 va cac module I/O &vac ket not vcfti nhau qua mot chuAn BUS

Om 5 day (Hinh 5), cho phep de clang the tao va Om sat cac giao dich ten BUS Dtya tren ca the giao tiep RS485 va protocol lien lac th6ng minh he thOng cho phep:

• Ket not 1 thiet bi dieu khien chinh (master) va 16 thiet bi I/O (slave)

• Cac module I/O duvc cap ngu6n tu, BUS

• CO co' the phat hien lOi khi truyen do lieu

• Co' the xoay yang token ring, cho phep viec cap nhat c10, lieu tai cac module khong bi gian doan khi ca sty co ten mot vai module

• Cho phep hot-swap, thay the module khi he thOng dang hoat d6ng

24V GND GND

Loadcell Connector 4 wire va 6 wire

Samples Rate >100 sps Exciting Voltage (ap cap

Firmware Tich hop sin cac tint' n5ng Calib, Setup va duoc digu

khign td PC ho5c module digu khign trung tam Nhiet d6 hoot dOng 0-60°C

Kich thudc Theo tai lieu dinh nghia layout dm module

Nguyen IY mei ki:

Module co kdt not RS232 (ho5c RS485) dg co thg lam viec trig tido vdi PC hoc kdt not vdi Board digu khign trung tam

Module duoc thidt kd cho oriel) cap nh5t chuong trinh firmware qua c6ng RS232 hay RS485

Module difoc thidt kd c6 cac TEST point d6 de clang cho qua trinh Calib va kigm tra chgt liking san phSm trong qua trinh san xua.t

Module duoc thiet kd CO chic nal-1g Watchdog dg tu reset h0 th6ng khi he th6ng treo,

co co chd thOng boo Iii khi phat hiOn he th6ng bi reset

- Module co kha nang detect khi dp ngu6n sut dud mOt mdc cho phep (5V),hay he th6ng bi mat ngu6n trong mOt thdi gian ngin, khi d6 he th6ng tic dOng khoa cac tin hieu digu khign, thOng boo vdi PC hoc module digu khign trung tam dd tranh cac trong trial digu khign sai

Module duoc thidt kd de"' co thg kdt not vdi cac module khac th6ng qua he th6ng bus chung (Common Bus), hay &roc kdt not vdi mOt module Monitor duy Wit qua Intenal Bus

- Module c6 60 nhd Flash de Im cac thOng s6 du hinh, dam boo khOng bi mgt khi mat ngu6n

10- ÷ Common Bus

- AnalogIP Out

Interface UART,I2C, SPI

Jumper Setting & LED

110 Pin

Power Loss Detect

Internal Bus

•

•

RS485 RS232

Samples rate > 100sps

Firmware Tich hop san cac tinh nang Calib, Setup va difoc digu

khign ti:i PC hoc module diet' khign trung tam Nhiet dO hoat d(sing 0-60°C

Kich thitdc Theo tai lieu dinh nghia layout dm module

Module co kgt not RS232 (ho5c RS485) dg co the lam yiec tryc tigp yOi PC hoac kgt

not ydi Board dieu khign trung tam

Module duoc thigt kg cho phep cap nhat chLiong trinh firmware qua c6ng RS232 hay

RS485

Module duoc thik kg CO cac TEST point dg dang cho qua trinh Calib ya kigm tra

chgt lifOng san phdrn trong qua trinh san xual

Module dudc thigt kg co chuc nang Watchdog dg tki reset he th6ng khi he th6ng treo,

co co chg thOng bao 161 khi phat hien he th6ng bi reset

Module c6 kha nang detect khi Ai) nguon skit did mOt mac cho pile') (5V),hay he th6ng bi mat ngutin trong mot thdi gian ngin, khi dO WO th6ng W d6ng khoa cac tin hiau didu khign, th6ng bao vdi PC hoac module didu khidn trung tam de"' tranh cac trang thai didu khidn sai

Module duoc thigt kg de"' CO thd kgt not vdi cac module khac th6ng qua he thong bus chung (Common Bus), hay duoc kgt n6i vOi mOt module Monitor duy nhgt qua Intenal Bus

- Module c6 b0 nhO Flash dd Wu cac thOng s6 cgu hinh, dam bao khOng bi mat khi mgt nguon

4.4 Module Digital

Module Digital c6 chtic nang hoat Ong nhu mOt b0 PLC don gian cho phep xit lj/ cac chac nang logic giria tin hidu d5u vao (digital input) va tin hidu d5u ra (digital output), cling nhu cho phdp kgt not vdi PC hay b6 xii lj/ trung tam dd doc trang thai cac port input, hay xugt ra cac port output Cac tinh nang dm module nay bao Om:

Nhret d6 hoat dOng 0-60°C

Kich thudc Theo tai HO dinh nghia layout cua module

Nguyen Ijr thiet ke:

- Module co kgt n6i RS232 (hoac RS485) dd co thd lam viac truc tigp vOi PC hoac kgt not vdi Board didu khign trung tam

Digitalin

Isolate Opto Couple

Isolate Buffer Opto

Couple Buffer

Module daoc thigt kg cho phep cap nhat chaong trinh firmware qua c6ng RS232 hay

RS485

Module duoc thigt kg co cac TEST point dg de clang cho qua trinh Calib va kidm tra

chit lacing san phdm trong qua trinh san xugt

Module duoc thigt kg co chic nang Watchdog dg tit reset fig th6ng khi hg th6ng treo,

co co chg thOng bao loi khi phat hign he th6ng bi reset

Module co kha nang detect khi ap nguon sat dudi mot mac cho phep (5V),hay hg

th6ng bi mgt nguon trong mOt thai gian ng6n, khi dO hg th6ng to Bong khod cac tin

higu digu khidn, thOng bao veil PC hoac module digu khign trung tam dg tranh cac

trong thai digu khign sai

Module daoc thigt kg dd co thd kgt not vdi cac module khac th6ng qua hg th6ng bus

chung (Common Bus), hay daoc kgt not vdi mOt module Monitor duy nhgt qua Intenal

Bus

Module co 136 nhd Flash dd luu cac thOng s6 cgu hinh, dam bao khOng bi mgt khi mgt

ngu6n

Jumper Setting

fi

Power Loss Detect

4.5 HO dieu hanh thol gian thtyc Linux

4.5.1 Nguyen ly

He dieu hanh thai gian thyc la he dieu hanh cho phep ngu,sod 15p trinh Cling dung Ay dyng cac tac vu thai gian thyc (realtime task) Cac tac vu thai gian thyc phai duvc thyc hien vai thai gian tre xac lap tai thieu Thad gian tre cua

he thong duvc dinh nghia nhu' sau:

- Thad gian giCra mat sty kien nhu, interrupt, timer vai thai gian bht d'hu thtyc hien tac vu xt:r19 sty kien,do

- Thad gian sai so tan suat (thai gian sai loch giCra cac Ian chay cua tac vu cluvc thiet ke thyc hien vai mat tan suat co dinh)

ThOng s6 quan trong nhet trong viec danh gia cac he dieu hanh thai gian thtyc

la thol gian tre xac lap tai thieu (WCT - worst case timing) CAn nhan manh

Sly khac nhau giCra thai gian tre xac lap trung binh thiroing duvc giai thieu cua cac he dieu hanh th6ng thuVng co tinh n5ng realtime nhu' Windows 2000, Windows NT, Linux Kernel WCT WCT dam bao that gian tre luOn nha hart mat gia tri, trong khi thai gian tre xac lap trung binh chi dam bao phAn Ian thai gian dap ryng se bi tre trong mot gia tri xac dinh, nhung khong bao dam 100% Dieu nay d5"c biet quan trong trong cac he thong dieu khien may, vi du mat tay may co sai s6 goc la 1° cho m6l micro-second tre, va sai so tre trong binh cua he thOng la 1 micro-second, nhung chi can mot Ian yeti sai so tre trong truVng hap x'eu nhAt la 20 micro-second, thi he thong duvc xem la khong dat you cau Ket qua tinh toan WCT cho he thong se &Tic trinh bay a MUC (4.5.5)

He dieu hanh Linux thai gian thyc la he dieu hanh Linux ma rang vai tinh n5ng thai gian thyc Chien lircyc hien thtyc he thong la Ay dyng mat ph5n 10i chuyen d6i tac vu dun gian va xac 15p cho cac tac vu thai gian thtyc He dieu hanh Linux nguyen thily se duvc chay nhu, mat process vai min do u'u tien thap nhAt Dieu nay dam s bac) cac tac vu that gian thtyc khOng the bi chan (preempted) bal he diet.) hanh Linux nguyen they, trong, khi van sir dung duvc cac Yu the cua he dieu hanh nay nhu' kha nang ket not mang, giao dien graphics, bao mat, Hien nay co 3 khuynh huVng chinh trong viec hien thtyc

he dieu hanh Linux thol gian thtyc:

RTLinux: phat then bad Dr.Victor Yodaiken va cac sinh vien vao nam 1997

tai vien cong nghe New Mexico Hien nay he dieu hanh nay &vac phat hien tai cong ty FSMLabs, mat cOng ty do Dr Victor Yodaiken thanh lOp Bay la phien ban he dieu hanh kha On dinh va thanh cOng, duvc ap dung trong

nhieu linh vuc khac nhau Chuang trinh realtime trong de tai nay duvc

phat then tO' phien ban ma nguOn mo, cua c6ng ty FSMLabs (lu'u

phien ban ma ngu6n mo, nay se co sy khac biet vai phien ban thirang mai

Interrupt control hardware

do cong ty nay cung cap) Th6ng tin chi tiet v6 chuang trinh nay c6 the duac tim a dia chi www.fsmlab.com

RTAI (realtime application interface): tuang to nhu RTLinux, nhung ,hien thuc cac tac vu realtime tip lap Ong dung (user space) Th6ng tin chi tiet co the tim a dia chi (www.rtai.org)

Realtime Linux tip MontaVista: day la mot cong ty hang cfau trong linh vuc Linux Embedded, chien luc thuc hien dm ho theo phuang phap "IRQ threads" dm Ingo Molnar, cho phep cac ham (lieu khien interrupt chay nhu' mot thread ci.la he lieu hanh, dieu nay giup giam thai gian tr6 xac lap dm

he thong

4.5.2 Ung dung RTLinux trong dieu khi& tty dOng hoa

Trong mot Ong dung dieu khien ty d6ng haa luOn co hai nh6m Ong dung chinh can cluac )(ay dung:

Chuang trinh dieu khien logic: logic dieu khien dm he th6ng duac m6 to qua ngOn ngO' PLC nhu LADDER,FBD, STL, cac logic nay se duac mot trinh bien dich (tOy theo hang san xuat) thOng dich va (16i ra ngon ngt:F may de c6 the lap trinh vao thiet bi M6t dac tinh rat quan trong trong cac Ong dung nay la cac logic (lieu khien phai ducyc clap Ong trong mot khoang

do chung ta can phai ap dung he dieu hanh thori gian thtic trong cac CPng

dung nay

Chuang trinh giao dien HMI: cho phep dinh nghia sty twang tac cua

sCy dung vai thiet va theo dOi mtt cac trtyc quan hoat d6ng cua he thong

Cac Ong dung nay khong you chu tinh nang thai gian thliPc do ban chat

phan CPng cua con ngc6i la chem so vai dap C.Png he thong

He dieu hanh Linux thai gian thcpc cOng du,gc chia ra lam hai nhOm cac tac

tac vu thai gian thcPc (realtime task) va cac tac vu th6ng thu,Ong dm he dieu

hanh Linux chuen Dieu nay tu,ang thich hoan toan v&I bai toan dieu khien tu,

d6ng hOa, chi -1g ta co the hien thu,c cac logic dieu khien beng cac realtime

task, dOng thai co kha nang )(ay cluing nhipng Cyng dung HMI vai cac tu,ceng tac

do hoa phU'c tap vO'i cac tac vu chuen cua Linux Hinh 10 mo ta kien trk hien

thu,c he thong:

Interrupt Con tro Ile r

R e a I-tim e Kerne I

Real-time PLC core Linux

PLC

1

Linux processes (H M I Application)

Hinh 10 Hien thcpc cac module dieu khien trong Linux Trong kien truc nay cac tac vu PLC du,qc cau hinh la cac tac vu tho'i gian thu,c

dam nhan cang viec xip 19 logic dieu khien nhu' AND, OR, PID,

BATCH1NG, Moi giao tie!) v&I cac module I/O va Cpng dung HMI, cOng nhu'

chieu giao tiep tu, cac O'ng dung nay vai cac tac vu PLC deu th6ng qua

Realtime PLC CORE (PLC_CORE), day la m6t tap hop cac chipc Wang lien lac

nhu' b6 nh& chung, lien lac fifo thai gian thtyc, b6 nha anh xa thiet bi (device

mapping) Hinh 11 mo to chi tiet to chU'c cua PLC_CORE, trong do:

• Shared mem: 16 vung nha Chung duvc truy xuAt 136i Ong dung HMI va cac tac vy PLC U'ng dung HMI thong qua vung nha nay CO the biet trong thai hopt dOng cue trong thiet bj trong he thong, tit, d6 bieu dien dual dung do hoa try'c quan cho ngu,o'l sO dung Trong khi cac tac vu PLC CO the thOng qua vung nh& nay de nhen cac thong so cau hinh he thong do ngu,erl six dung nhep vao tir Ong dung HMI

dieu khac biet cua vung nha nay 16 thong tin yen duvc ngay ca khi thiet bj a trong thai cat ngu6n Thong thu,O,ng nhCrng tham s6 trong thai hopt dOng cOa PLC duvc gia, trong Yung nay, de khi khoi dOng he thong CO the chpy tier) c6ng viec Bang thy'c hien troac khi tat may

de trao dOi nhOng thong tin CO tinh chat thee' gian thy,c, vi nhu, bieu d6 cOa mOt tin hieu analog trong he thong NhOng gia trj can I6y rn6u se duvc tac vu PLC dim vao trong Fifo, Ong dung HMI se doc gia trj tu, fifo va ye len man hinh, dieu nay dam bao cac rnAu d0, lieu kh6ng bj Rik do th&i gian tre xac lep cua Crng dung HMI 16 Ian han rat nhieu so vai t6c d6 16y rn6u do, lieu

he thOng, mol than tac dcc/ghi vung nha nay c,6 tac dOng tier) tai trong thai input, output cue cac module I/O

D•vIc• Device 2 Oevic• 3 ovIc• k

4.5.3 T6 chirc source chiyang trinh

Toan 130 ma thu,c hien dm dki, an: ma chiming trinh kernel, ma chtyang trinh dieu khien thai gian thu,c (real-time), ma khol thing he thong, (ngoai trta, ph5n

ma Bios he thOng ma theo dt), kien doan ma nay cung se du,ac se duvc viet lai

de tang tOc d6 khol dOng he thong) deu duvc xay Ong tim ma ngu6n ma hoac

do nhom nghien cO,u to phat then Hinh 12 m6 t5 cAu trtac ma chu,ang trinh cau

thanh nen he thOng, trong dO:

• Kernel source: ma ngu6n chtyang trinh sctaa Linux kernel, phien ban dung trong du an nay la 2.4.20 ThOng tin ye he diet.] hanh nay va ma nguon chu,ang trinh co the duvc tim tal www.linux.org

• Glibc source: ma ngu6n thu' vien chuAn cho cac tic vu toan hoc, truy xu5t I/O, xCv l9 chu6i, phien ban trong du, an nay la glibc-2.3.2 ThOng tin y6 ma

co

nguon the tim tal dia chi http://www.gnu.org/software/libc/Iibc.html

• Busybox: ma ngu6n,cac chiyang trinh khol dOng dm he dieu hanh Linux Thong tin ye ma nguon co the tim tal www.busybox.orq

• QT Trollech: ma ngu6n thu' vin giao dien do hoa, cho phep x'ay citing cac Ong dung do hoa vii kich thutec nho, Vic do cao da'c biet phta hap cho cac Ong dung embedded system Th6ng tin ye ma nguon co the tim tal www.trolltech.com

• RTLinux source: ma chivang trinh ma (Ong tinh nang realtime cho he dieu hanh Linux Ma ngu6n chiming trinh co the tham khao tim www.fsmlab.com

• Cac module chu,ang trinh con lai du,ac nh6m nghien avu x5y dung chuyen

de h6 tra cho cac ring dung dieu khien dOng hOa

Ramdisk image

// Busybox source

(open source) Mit code & config file

opr code

QT designer C source

V

plc_code.o plc C source

Reattime PLC core

Chudng tnnh ang dung

plc logic flowchar Tli ►

Flash Programming RTLinux source

(open source) ► Rea!time driver Build Image Tool ) Tool

Hinh 12 So' dO to chin source chuang trinh

4.5.4 Qui trinh phat tri"e'n mot tin dung tkr diing hoi

thanh canh tranh nhu'ng de CO the ducyc ch5p nh5n rOng rai tren thi truang thi phai co cac cong cu phat trier] va go' r6i (debug) chuang trinh th5t de dang

va thu5n tien cho ngivai sir dung DO chinh la l do nhom nghien am rat quan tarn tai viec )(ay dung cac chin nang chu,ang trinh cho phep ngutei sip dung thiet ke chuang trinh tren PC, simulation va download vao thiet bi a thu'c

nhu' cho phep debug online a kiem tra logic chuang trinh Tuy nhien

do thai gian co han, nhom nghien civu chi co the thuc, hien mot phan muc tieu nay va dinh nghia cac giao tiep macho phep nang cap he th6ng trong tuang lai Hinh 13 mo to qui trinh xay dung va thcfc hien mot ipng dung, trong do:

• Nguai sir dung co the dung ng6n ngip Ladder, IEC 61131-3 hoac C a mO

ta logic dm he thong (luiu 9 nhOing module duac to dam van chu'a &vac hien thin tuy nhien nhom phat trier' dang CO ke hoach xay citing cac cong

cu nay trong mot tuceng lai gan) Nhipng ngon ngCp tren se duvc 116i qua ma chuvng trinh C va sau do se duac !Dien dich val thu' vien PLC de tao ra

RC care Bray

Btona & Wti

Linux PLC Controller

( Kernel )

Upload &

debug agent Plc ccde.o )

Liru< FLOG :Adler

Doan ma chwyng trinh plc_code.o va opr_code se duvc nap vao he thong dieu khien th6ng qua mot cong cu upload &debug nhu) hinh 13 (cong cu

nay cung co the duvc dung a debug chtyang trinh chay tren Linux-PLC,

tuy nhien chin n5ng nay chi han the a mire ma ngu6n C)

Hinh 14 Upload chwyng trinh

4.5.5 Phan tich cac th6ng s6 hoat Ong cua he thong

NOi dung Mlle nay trinh bay ket qua va cach thin tinh toan theYi gian tr6 xac lap trong truVng hap xau nhat (WCT) Thin nghiem duvc thtyc hien bang viec chay Cvng dung rt_process.o de do SI, khac nhau giCpa cac Ian tac vu realtime chay tren ljt thuyet va so vai thu'c te, trong cac truting hgp:

• He th6ng kh6ng tai (chi co 1 rt_process thu,c hien)

• He th6ng vai cac nhieu process chay ding thoi vai mire dO 1.PU tien thap ham

Ung dung rt_process.o lien tuc doc va ghi cac gia tri thoi gian tt:p thiet bi RTC (realtime clock) a so sanh theYi gian chay thu'c to cua tac vu so vai thi gian

thuyet Dlyeri day la bang ket qua thip nghiem:

Kets luan: WCT cua he dieu hanh Linux thol gian thu'c la 38ps (nho hurt rat nhieu so vai he dieu hanh Linux thOng thty&ng la khoang vai chuc ms), ma ra kha nang Ong dung v61 cac he thong dieu khien tic dO cao (Vi du tic do nay

dm he th6ng cho phep dieu khien servo vai theyi gian dap Ong khoang 10KHz)

5 Bao cao ket qua thu'c t6 tren WO thong can Binh luong

Tinh nang thtyc to cua he thong dieu khien realtime Linux duvc chipng minh

trong mot san phAm can kiem tra kh6i Ityang cua cong ty CAC Trong he thOng

nay Linux PLC se thay the 136 dieu khien PR1713 dm hang Global Weighing,

de thtyc hien viec xac dinh kh6i luvng mot vat the di vao va ra bang tai can thing, thtyc hien viec lay mau khoi lung va tinh tOan kh6i luang dm vat the vai tic do cao He thong co trang man hanh SCADA (hinh 17) cho phep ngueYi sir dyng tuang tac de chon the de) can, xem tinh trang hoat ding dm he thong va hien thi cac thOng tin th6ng ke dm qua trinh san xuat

Duai day la ban ye hoat ding cua he th6ng (Hinh 15) bao g6m mot bang tai can ( B1) va hai bang tai truyen ding (B2) Hai bang tai chuyen Ong B2 dugc dieu khien vai van tic co dinh, trong khi van tic bang tai B2 duvc dieu khien bai Linux PLC

0.1

M2_START rSENSOR_INr

Loadcell Card

PC104 Main

Analog Card

MSSTAITI

€.10 Hinh 15 So' do boat dOng bang tai can

Demo PA.pplication Linux Controller System