Chapter 4 Sequential Instructions

Transcription

1 Chaper 4 Sequenial Insrucions The sequenial insrucions of FBs-PLC shown in his chaper are also lised in secion 3.. Please refer o Chaper, "PLC Ladder diagram and he Coding rules of Mnemonic insrucion", for he coding rules in applying hose insrucions. In his chaper, we only inroduce he applicable operands, ranges and elemen characerisics, funcionaliy. 4. Valid Operand of Sequenial Insrucions Operand X Y M SM S T C TR OPEN SHORT Insrucion Ranges X255 Y255 M M9 M92 M2 S S999 T T255 C C255 TR TR39 NOT TU TD LD LD NOT LD TU LD TD AND AND NOT AND TU AND TD OR OR NOT OR TU OR TD OUT OUT NOT OUT L ANDLD ORLD TU TD NOT OUTS OUTR 4-

2 For he relays marked wih a symbol in he special relay able(please refer o secion 2.3)is wrie prohibied. In addiion, TU and TD conacs are no suppored for hose relays as well. The operands marked wih a * symbol in he able shown above should exclude hose special relays. 4.2 Elemen Descripion 4.2. Characerisics of A,B,TU and TD Conacs Inpu from he inpu erminal block ON OFF A conac Elemen saus B conac Elemen saus : scan ime TU conac Elemen saus TD conac Elemen saus The waveform shown above reveals he funcion of A, B, TU and TD elemens by exercising he exernal inpu form OFF o ON hen OFF. TU (Transiion Up): This is he Transiion Up Conac. Only a rising edge ( ) of he referenced signal will urn on his elemen for one scan ime. TD (Transiion Down): This is he Transiion Down Conac. Only a falling edge ( ) of he referenced signal will urn on his elemen for one scan ime. TU and TD conac will work normally as described above if he change of he saus of he valid referenced operands lised in he Valid Range of he Operand of Sequenial insrucions able are no driven by he funcion insrucions. Remark: For TU(TD) elemens which operand is of relay will urn on afer he firs ime he corresponding relay ge driven from o ( o ). When he nex ime he corresponding relay ge driven from o ( o ) he TD(TU) elemen will urn OFF. Care should be aken while here is a muliple coil usage siuaion exised in he ladder program. This siuaion can be bes illusraed a below. In he waveform we can see TU elemen only urn on beween b and e ime which only he TU elemens exised beween rung and rung 2 can deec he rising edge, while oher TU elemens ou side hese wo ladder rungs will never aware he occurrence of he rising edge. For he relays do no have he muliple coil usage in ladder program, The ON saus of corresponding TU or TD elemen can be susained for one scan ime, bu for relays which conrary o above, he urn on ime will shorer han scan ime as illusraed a below. 4-2

3 Ladder Diagram Mnemonic code X a OUT OUT Y b Y c OUT X d Y e N imes scan N+ imes scan Scan Time a b c d e a b c d e A A : The inernal accumulaor of PLC Besides he TU/TD insrucions which can deec he saus change of reference operand, FBs-PLC also provides he insrucions o deec he change of node saus (power flow). For deails please refer he descripions of FUN4 (DIFU) and FUN5 (DIFD) insrucions OPEN and SHORT Conac The saus of OPEN and SHORT conac are fixed and can be changed by any ladder insrucions. Those wo conacs are mainly used in he places of he Ladder Diagram where fixed conac sauses are required, such as he place where he inpu of an applicaion insrucion is used o selec he mode. The sample program shown below gives an example of configuring an Up/Down couner (UDCTR) o an Up couner by using he SHORT conac. PSU 7.UDCTR CV : R CUP LD SHORT U/D PV : R LD X FUN 7 CLR CV: R PV: R 4-3

4 FUN7 is he UDCTR funcion. While rising edge of CK inpu occur, FUN7 will coun up if he U/D saus is or coun down if he U/D saus is. The example shown above, U/D saus is fixed a since U/D is direcly conneced from he origin-line o a SHORT conac, herefore FUN7 becomes an Up couner. On he conrary, if he U/D inpu of FUN7 is conneced wih an OPEN conac from he origin-line, he FUN7 becomes a DOWN couner. PSU 7.UDCTR CV : R CUP LD OPEN LD X U/D CLR PV : R FUN 7 CV: R PV: R Oupu Coil and Inverse Oupu Coil Oupu Coil wries he node saus ino an operand specified by he coil insrucion. Inver Oupu Coil wries he complemen saus of node saus ino an operand specified by he coil insrucion. The characerisics depics a below. OUT Y OUT NOT Y Reenive Oupu Coil The coil elemen can be caegorized ino wo ypes, namely Reenive and Non Reenive. For example, M~M799 can be specified as he Reenive coils and M8~M399 can be specified as he Non Reenive coils. One way o caegorize he relay ype is o divide he relays ino groups. Though his mehod is simple bu for he mos applicaions he coils needed o be reenive may be in a random order. FBs-PLC allows user o se he reenive saus of coil individually. When inpu he program wih mnemonics insrucions, if pu an L afer he OUT insrucion can declare his specific relay as reenive oupu. This can be shown in he diagram below. L OR Y AND NOT X OUT L Y From he above example, if urn he "ON" hen "OFF", will keep a "ON". When change he PLC sae from RUN o STOP hen RUN or urn he power off hen on, he sill keep a ON sae. Bu if use he OUT insrucion insead of he OUT L, saus will be OFF. 4-4

5 4.2.5 Se Coil and Rese Coil Se Coil wries ino an operand specified. Rese Coil wries ino an operand specified. The characerisics depics a below. OUTS OUTR SET RST 4.3 Node Operaion Insrucions A node is he connecion beween elemens in a ladder diagram consising of sequenial insrucion elemens (please refer o Secion.2). There are four insrucions dedicaed for node saus operaion in FBs-PLC. The wo insrucions, OUT TR and LD TR, have been discussed in Secion.6 of his manual. Using he diagram below, he hree node operaion insrucions NOT, TU and TD, are illusraed. Node B AND X NOT OUT TR TU OUT Y Node A LD TR TD OUT Y 4-5

6 Node A Node B Incerse Inverse differenial down differenial up : Scan ime 4-6