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Trng i Hc Bch Khoa Khoa C Kh B mn C in T

Bi thc hnh/th nghim s 04:

Chc nng c bn ca PLC

1. Gii thiu

PLC l b iu khin lp trnh m ngi s dng c th lp trnh thc hin mt lot hay trnh t

cc s kin. Cc s kin ny c kch hat bi tc nhn kch thch (ng vo) tc ng vo PLC hoc

qua cc hat ng c tr nh thi gian nh th hay cc s kin c m. Mt khi c s kin c

kch hot, tht s l n bt ON hay OFF thit b iu khin bn ngoi (ng ra).

Mc tiu:

Gip ngi hc s dng c thit b iu khin PLC qua m hnh Melsec ca Mitsubishi.

Lp trnh c cc tc v logic v cc b nh th cng nh cc b m.

2. Thit b thc hnh/th nghim

2.1 Thnh phn

- My tnh

- M hnh PLC Mitsubishi FX3G-14MT

- Cp USB

- Phn mm lp trnh GX Developer 8.85

2.2 S lc c tnh thit b

- Thit b c cp ngun

- C tng s 14 ng vo/ra. Trong c 8 ng vo (X0 X7) v 6 ng ra (Y0 Y5).

- Cc ng ra l transistor c ni dng sink.

3. Ni dung thc hnh/th nghim

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Thc hin chng trnh trn my tnh, truyn vo PLC, tc ng ng vo v quan st ng ra.

3.1. Thi lng: 3 tit cho mi nhm gm 4-5 sinh vin.

3.2. Trnh t thc hin:

3.2.1 Cc bi tp c bn:

a/ Kha ln: y l mt on chng trnh m nht thi ch c mt ng ra c tc ng khi

c tn hiu ng vo tng ng.

Vi X2, X3: hai ng vo tng ng vi hai cng tc.

Y0, Y1: hai ng ra ni tng ng vi hai bng n.

Hng dn vit chng trnh:

Khi ng chng trnh: Start > Programs > MELSOFT Application > GX Developer.

Project/New project/chn FX3G/nhn OK.

Vit chng trnh:

Ld x2

Ani y1

Out y0

Ld x3

Ani y0

Out y1

Nhn F4 kim tra chng trnh

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Truyn chng trnh qua PLC: khi truyn chng trnh qua PLC, bt buc PLC phi ch

Stop.

- Online/Write to PLC

- Chn MAIN/ click Execute

- Click Yes

- Click OK

Trn PLC: chn Run

Online/monitor/start monitor

Tc ng cc ng vo v quan st s hot ng ca ng ra.

Yu cu: Nu tc ng c hai cng tc X2 v X3, th n no sng? Quan st v nhn xt.

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b/ n chp tt: on chng trnh cho ta bit c b nh hot ng nh th no.

Yu cu: V biu theo thi gian ca tn hiu Y1?

c/ m sn phm: B m trong mch c th tc ng ng ra khi s tn hiu ng vo.

Yu cu: Khi thay ng vo X2 bng cng tt thng ng, quan st b m khi PLC hot

ng, gii thch. Khi no gi tr b m thay i?

3.2.2 Cc bi tp ng dng:

a/ Bi 1: Control of escalator

Yu cu: Vit chng trnh PLC iu khin hot ng ca thang my cun nh sau:

- Khi cng tc PD0 (pass detection) ON, th n bo v thang cun bt u hot ng (gi s

thang cun ch i ln).

- Khi cng tc PD1 ON, th n bo v thang cun dng.

Lu : PD0 v PD1 l cc cng tc khng t gi.

I/O assignments Input Pass detection switch 0: PD0 X001 Pass detection switch 1: PD1 X003 Output Illumination lamp Y000 Escalator drive output Y003

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b/ Bi 2: A simple counter

Yu cu: Vit chng trnh PLC iu khin h thng trn bit:

- Cm bin PC1 dng nhn bit c sn phm chy qua.

- Khi s sn phm t n 50, th n LP1 s bo. Nt nhn PB2 dng khi to li gi tr

b m.

c/ Bi 3: A 24 hour clock using counters

Device PC device Description PC1 X000 Bottle counting photocell LP1 Y000 Stop loading lamp PB2 X001 Reset counter push button

C000 Bottle counter / count

Device PC device Description SEC C000 A count of the number of elapsed seconds MIN C001 A count of the number of elapsed minutes HRS C002 A count of the number of elapsed hours

M8013 A 1 second clock pulse

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Yu cu: Vit mt on chng trnh PLC hin th s gi, s pht v s giy ca ng h.

Khi h thng hot ng th chng trnh thi gian bt u t 00:00:00.

d/ Bi 4: A simple dual control system

Yu cu: Vit mt on chng trnh PLC iu khin hai bng n nh sau:

- Hai bng n cu thang LP1 v LP2 cng sng/cng ti.

- n cu thang sng khi hai cng tc LS1 v LS2 c cng trng thi.

e/ Bi 5: Time sequenced operations

Device PC device Description LS1 X002 Light switch top of stairs LS2 X003 Light switch bottom of stairs LP1

Y001 Lamp contact Top of stairs

LP2 Bottom of stairs

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Yu cu: Vit chng trnh PLC iu khin hot ng ca my git trn theo trnh t sau:

- Chu trnh vt ca my git bt u sau khi nhn nt SPIN (PB1).

- Ban u ng c ca my git lm vic mc thp MTR1 = 1.

- Sau 25 giy, c thm tn hiu MTR2 = 1 v my git chuyn sang mc tc cao.

- Sau 20 giy, MTR2 = 0. Khi my git lm vic mc tc thp trong khong 15

giy trc khi dng hn.

Device PC device Description PB1 X007 Manual selection spin cycle

MTR1 Y005 Slow spin / speed cycle MTR2 Y006 High spin / speed cycle

T030 Duration of slow speed cycle T031 Duration of high speed cycle T032 Deceleration time

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4. Kt qu thc hnh/th nghim

4.1. A simple counter

Chng trnh PLC:

4.2. A 24 hour clock using counters

Chng trnh PLC:

4.3. Time sequenced operations

Chng trnh PLC:

H v tn sinh vin: ............................................................ MSSV:....................... Nhm: ............

Ngy thc hnh / th nghim: .............................................. K tn: ..............................................

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5. Ti liu tham kho

[1] Phm Cng Bng, bi ging B iu khin kh lp trnh.

[2] Mitsubishi, Your First PLC Introduction.