6ES5135-3KB13

6ES5135-3KB13

 

以NT6000的ELIN網(wǎng)為例，雖然也是基于工業(yè)以太網(wǎng)的，但其應(yīng)用層協(xié)議是積累了近30年的無主令牌LIN網(wǎng)協(xié)議，在1M的OLIN，2.5M和20M的ARCNET上都有長期成功的應(yīng)用。ELIN網(wǎng)上，各站平等，不存在主要管理站。而且數(shù)據(jù)通訊是以模塊為單位的結(jié)構(gòu)化數(shù)據(jù)，數(shù)據(jù)管理能力非數(shù)據(jù)表方式可比。

    以PID模塊為例，其中的基本數(shù)據(jù)有PV、SP、OP，采用數(shù)據(jù)表的傳輸方式，你必須先定義PV、SP、OP的數(shù)據(jù)地址為01、02、03，其它的站也以數(shù)據(jù)表的方式接收數(shù)據(jù)，但是01是什么數(shù)據(jù)？02是什么數(shù)據(jù)？必須通過數(shù)據(jù)定義表才能還原。數(shù)據(jù)表的管理方式煩瑣易錯(cuò),一個(gè)大型系統(tǒng)的上萬點(diǎn)數(shù)據(jù)采用這個(gè)方式,平鋪在數(shù)據(jù)表中進(jìn)行管理，是非常可怕的。而NT6000DCS以模塊為單位的結(jié)構(gòu)化管理，將一個(gè)PID作為一個(gè)模塊進(jìn)行處理，要訪問其PV值，首先訪問其模塊，以PID.PV的形式來管理。這就將所有平鋪的數(shù)據(jù)，分類歸屬集中到一個(gè)個(gè)小盒子中，按模塊.分量的方式進(jìn)行管理，管理的效率大大提高。PLC數(shù)據(jù)通訊交換的問題，主要源于PLC長期以來做為一個(gè)獨(dú)立裝置在發(fā)展，沒有系統(tǒng)概念；而且主要應(yīng)用在小型控制系統(tǒng)中，問題暴露得并不明顯，所以發(fā)展較慢。目前也有一些大型PLC在這個(gè)方面有所提高，但是要達(dá)到DCS的水平還需要一個(gè)相當(dāng)長的過程。

價(jià)格好++++++++莫+++++++++++++瘋狂降價(jià)

貨期短+++++++++格++++++++++渠道好

產(chǎn)品好+++++++++++電++++++++原裝進(jìn)口

數(shù)量多+++++++++++++氣++++++++大量庫存停產(chǎn)備件

售后服務(wù)好+++++++++++++！++++++質(zhì)量保證 

 

咨詢熱線：18050035902/0592-6808394，QQ：1982497648（郵箱+@qq.com）

 

　

    2．3、組態(tài)維護(hù)功能組態(tài)維護(hù)功能包括邏輯組態(tài)、下載修改、運(yùn)行調(diào)試、遠(yuǎn)程診斷等。

    早期，PLC以梯形圖為主，DCS以模塊功能圖為主。經(jīng)過多年的發(fā)展，國際電工委員會(huì)通過IEC1131-3標(biāo)準(zhǔn)規(guī)定了五種編程語言,目前主流的DCS和PLC都表示符合這個(gè)標(biāo)準(zhǔn)，支持其中的幾種或全部編程語言。從開發(fā)效率和程序可讀性來考慮，模塊功能圖和順序功能圖越來越成為主要的編程方式，梯形邏輯和結(jié)構(gòu)化文本成為了自定義模塊的開發(fā)工具。大型PLC在組態(tài)方式上越來越像DCS，差距在逐漸縮小，而小型PLC仍然以梯形圖為主。

    DCS經(jīng)過多年的發(fā)展，積累了大量的高級算法模塊。例如NT6000具有的設(shè)備級模塊，在一個(gè)模塊中集中完成了面向設(shè)備的基本控制和故障報(bào)警功能，在網(wǎng)絡(luò)通訊中也已此模塊為單位進(jìn)行傳遞，大大提高了軟件開發(fā)的效率。一個(gè)設(shè)備極模塊相當(dāng)于0.5K的梯形圖邏輯量，PLC要完成同樣的功能，就要煩瑣得多了。

    在下載修改、運(yùn)行調(diào)試、遠(yuǎn)程診斷方面，PLC缺乏解決方案。而DCS從一設(shè)計(jì)之初就是從系統(tǒng)需要的角度出發(fā)的，有著多年積累的完善的解決方案。以NT6000DCS為例，系統(tǒng)既可以在線修改控制策略，也可以在線下載控制策略，修改和下載過程中，對系統(tǒng)的正常運(yùn)行沒有影響。NT6000DCS有完善的虛擬DCS功能，不但可以用于組態(tài)邏輯的驗(yàn)證，而且能夠構(gòu)建成完整的虛擬DCS與模型相連，完成系統(tǒng)的仿真調(diào)試。NT6000DCS具有完善的安全措施，提供基于廣域網(wǎng)的遠(yuǎn)程調(diào)試方案。

    2．4、硬件封裝結(jié)構(gòu)

    PLC一般為大底版式機(jī)架，封閉式I/O模件，封閉式結(jié)構(gòu)有利與提高I/O模件的可靠性，抗射頻、抗靜電、抗損傷。PLC模件的I/O點(diǎn)數(shù)有8點(diǎn)、16點(diǎn)、32點(diǎn)。

    DCS大部分為19英寸標(biāo)準(zhǔn)機(jī)箱加插件式I/O模件，I/O模件為裸露式結(jié)構(gòu)。

ALLEN BRADLEY 855TS-B24D6 TOWER LIGHT STACK ASSEMBLY, SERIES B, NIB

 

ALLEN BRADLEY ArmorBlock MaXum 8 I/O MODULE 1792D-8BIO8E SER. B *NEW*

 

PEPPERL + FUCHS 110/120VAC ISOLATED SWITCH AMPLIFIER WE77/EX2-0T

 

SCHNEIDER MODICON TSX PREMIUM OUTPUT MODULE TSXDSY16S4

 

M SYSTEM 120VAC THERMOCOUPLE TRANSMITTER TCS-4A-F

 

ALLEN BRADLEY MEMORY COMMUNICATION MODULE 1775-MX

 

ALLEN BRADLEY SP-135774 CURRENT TRANSFORMER KIT, 3-30 Hp, NIB, SEALED

 

LMI 120V 10.00A 1/2" NPT *MISSING POWER CORD* ConDUCTIVITY ConTROLLER DC4000

 

SQUARE D FUSIBLE DISConNECT SWITCH & HANDLE MECHANISM 9422ATCF331 NIB

 

GE 3 POLE 7.5 HP 480 V MAGNETIC REVERSER LDR01AD SEALED

 

ALLEN BRADLEY PCB BOARD 900034 / 8000-KA

 

HF ConTROLS ConTROL BOARD AFS-VS-01B *NEW*

 

KAWASAKI ConTROL BOARD 50999-1650R10

 

VALENTINE GAGING SYSTEMS ConTROL BOARD 766G101-L01 REV. F

 

RANSBURG ConTROL ASSY 74727 PCB 74726 DISPLAY DRIVER ASSY 74731 PCB 74730

 

COOPER GARDNER DENVER ConTROL BOARD ISIC 1.3

 

KEITHLEY 32-CHANNEL SOLID-STATE I/O SYSTEM BACKPLANE PCB MSSR-32 14071 REV. C

 

FUJI ELECTRIC MICREX-F PROGRAMMABLE ConTROLLER FPB30R-A10

 

HonEYWELL MICRO SWITCH LOG CARD FE-LOG5-14 *NEW*

 

KEITHLEY 32-CHANNEL SOLID STATE I/O SYSTEM BACKPLANE PCB MSSR-32 / 14071 REV. B

 

ALLEN BRADLEY ConTROL BOARD 8000-KA 9000340

 

SUMITOMO HEAVY INDUSTRIES ConTROL BOARD SXEX SA765603BC

 

VOGEL 250V 0.8A PRECISION ELVEL SWITCH WS 33-2

 

HonEYWELL CHART RECORDER DISPLAY & KEYPAD BOARD 46182733-001 / 46182735-001

 

BEHR SERVO AMPLIFIER MODULE 77435

 

BAILEY ConTROLS I.O.X.M. BOARD 6634165B1

 

PCME ConTROL BOARD DA2104

 

CINCINNATI TEST SYSTEMS OPERATOR PANEL PMI REV. B

 

PILLAR INDUSTRIES MARK 11 I/O BOARD AB7133-2 (B)

 

WESTINGHOUSE ADVANTAGE ConTROL MODULE 9996D11 1A49102H21

 

PILLAR INDUSTRIES MARK 11 I/O BOARD AB7133-1(H)

 

HELLER ConTROL BOARD A 23.029 016-000/7829

 

YASKAWA ELECTRIC I/O BOARD JANCD-I004B

 

IDC DIGITAL PRESS LOAD MonITOR TM81-EK

 

INDRAMAT ConTROL BOARD TVM 109-524-3201a-1?1

 

INDRAMAT ConTROL BOARD TVM 109-524-3201a-1?2

 

EUCHNER SAFETY RELAY MODULE ESM-BA302

 

FANUC ROBOTICS I/O BOARD A20B-0008-0540/?01A

 

SCHNEIDER TELEMECANIQUE 285A, 600VAC MOTOR ConTACTOR LC1F265

 

TOKYO AUTOMATIC MACHINERY WORKS LTD BOARD PCB SERVO TAM553

 

YASKAWA ELECTRIC ConTROL BOARD ETC008772-S0200

 

TOKYO AUTOMATIC MACHINERY WORKS LTD COUNTER BOARD PCB COUNTER TAM552R1

 

TOKYO AUTOMATIC MACHINERY WORKS CPU BOARD PCB CPU TAM-551

 

ALLEN BRADLEY BULLETIN 1774 PLC PROGRAMMABLE ConTROLLER 1778-P2 SER. D

 

BALOGH EUROCARD PARALLEL ConTROL CARD W/ base CLC-81

 

MITSUBISHI ELECTRIC POWER SUPPLY BOARD A850GOT-PW / BKO-C10500H01

 

CUTLER-HAMMER ConTROL MODULE 9996D11 30-17913-2

 

BALOGH EUROCARD PARALLEL ConTROL CARD W/ base CLF 16

 

ABB OPERATOR INTERFACE BOARD 3HAC 0017-1/0

 

ABB BREAK RELEASE UNIT 3HAA 0001-ADX/2

 

HANSEN TECHNOLOGIES FROST MASTER DEFROST ConTROLLER FM-01

 

MARSH MCBIRNEY FLO-SYSTEM FLOWMETER MODEL 253-0a

 

SMARTEYE CPU ConTROLLER BOARD SP1001/04

 

KAWASAKI ConTROL BOARD PCB 50999-1361R30

 

YASKAWA ELECTRIC BACK PLANE RACK JZNC-MRK09-2

 

INGERSOLL RAND TORQUE ConTROLLER TMAD1-A *PLUG/CLIP*

 

SQUARE D SY/MAX MODEL 600 PROCESSOR CLASS 8020 TYPE SCP632 *PARTS OR REPAIR*

 

PHOENIX ConTACT INTERBUS-S 24VDC BUS TERMINAL MODULE 2754435 IBS ST 24 BK-LK

 

PERFORMANCE FEEDERS 115VAC 50/60HZ VIBRATORY FEEDER ConTROLLER PF-2

 

IAI RCP2 ROBOTIC CYLINDER ConTROLLER RCP2-C-RMA-I-PM?-0-P

 

FANUC ROBOTICS TEACH PENDANT A05B-2051-C143 *BAD*

 

FANUC OPERATOR INTERFACE ConNECTION BOARD A16B-2200-0660/?05A *PARTS/REPAIR*

 

PIAB 0.4-0.6MPA CLASSIC VACUUM PUMP M25B6-EN *DENT*

 

FANUC ROBOTICS 2 AXES ConTROLLER BOARD A16B-2200-0252/?05C *CLEANED/REPAIR?ED*

 

VIC ConTROL CIRCUIT BOARD 584-301 281-315-1001 REV-B

 

VIC ConTROL CIRCUIT BOARD 584-304 281-345-1006 REV. B

 

USON INPUT OUTPUT I/O MODULE INTERFACE 403-X300G

 

AEG RESISTANCE SWITCH 706619

 

SCHNEIDER TSX QUANTUM COM/ASCII MODULE 2xRS232 140 ESI 062 10 *FOR REPAIR*

 

ATI INDUSTRIAL AUTOMATION MODULE 9120-S26-M *NIB*

 

VeeArc Micro7000 5HP AC DRIVE MCF401K0 *INCOMPLETE, NO ConTROL BOARD*

 

DENGENSHA KAWASAKI 115VAC SOLENOID DECOMSTAR 70 WELD ConTROL RWC-70RC.SIA

 

DENGENSHA KAWASAKI DECOMSTAR 30 WELDING ConTROL RWC-31RC W/ 24VDC SOLENOID

 

DENGENSHA KAWASAKI DECOMSTAR 30 WELD ConTROL RWC-31RC W/ 115VAC SOLENOID

 

STANLEY FASTENER SYSTEMS TORQUE ConTROLLER T701 *PARTS OR REPAIR*

 

FANUC ROBOTICS MAIN CPU PCB A16B-3200-0040-?07D *NO DAUGHTER BOARDS*

 

YASKAWA ELECTRIC AC DRIVE POWER ConTROL BOARD YPCT31235-1D ETP615505

 

FANUC ROBOTICS 24VDC OUTPUT MODULE AOD08C A03B-0819-C151 *NEW*

 

BERGER LAHR ConTROLLER ? KSO30

 

EFD ConTROL CARD PCB TYPE GIIF

 

PREFERRED ENGINEERING ConTROL BOARD PCB PE2046B

 

YASKAWA I/O BACKPLANE RACK BOARD JZNC-MRK09-1

 

YASKAWA I/O BACKPLANE RACK BOARD JZNC-MRK09-2

 

INDRAMAT MT-CNC ConTROLLER MODULE CPUB 03-01-FW 261367

 

FESTO 87PSI 6 BAR MULTI VALVE ConTROL MODULE IT-IF-10/3 DC 24V

 

MonTRONIX TOOL MonITOR TS50 W/ USER'S GUIDE

 

SPANG 125KVA 480V 150A AC POWER ConTROL UNIT LC7G5-A-2151010

 

TEXAS INSTRUMENTS ConTROL BOARD PWB 2490870-0002 REV. C

 

SIERRA MASS FLO METER 780S-FM-F6-E2-P?2-V4-DD-0

 

RELIANCE ELECTRIC 1.7KVA 1HP VARIABLE SPEED AC DRIVE 1AC2001

 

SICK ConTROL UNIT LGTN101-311

 

CINCINNATI MILACRON MEMORY BOARD 3-531-3581A

 

MOISTURE REGISTER PRODUCTS 901 AUTO RANGE BOX ASSEMBLY 552524

 

INGERSOLL RAND SINGLE CHANNEL METER 90017393

 

NAMCO LIMIT ConTROL SWITCH EA990-10023 2096 *NIB*

 

DAYTRonIC DC STRAIN GAGE PANEL 4077

 

KAWASAKI ROBOTICS 1BP-55 ConTROL BOARD 50999-1384R04

 

KAWASAKI ROBOTICS 9ZR-33 ConTROL BOARD 50999-1295R31

 

KAWASAKI ROBOTICS 9ZR-33 ConTROL BOARD 50999-1295R33

 

KAWASAKI ROBOTICS 9ZR-33 ConTROL BOARD 50999-1295R32

 

SCHNEIDER MODICON TSX QUANTUM RELAY OUTPUT MODULE 16X1 140 DRA 840 00

 

NSD CORPORATION VS-CYLC CYCLE ConTROLLER VS-CYLC-UNNP-1-?1.0

 

ALLEN BRADLEY ArmorPoint ETHERNET MODULE 1738-AENT SER. A F/W REV. 2.004

 

ALLEN BRADLEY COMMUNICATION INTERFACE CARD 1784-KTXD SER. B

 

INDRAMAT SERCOS INTERFACE MODULE DSS 1.1

 

ALLEN BRADLEY BAR CODE DECODER 2755-DM6

 

ANALOG DEVICES ISOLATED V INPUT MODULE 3B31-02 *NEW*

 

PRESSTEK UNIVERSAL BACKPLANE BOARD AEE01271 REV. C

 

LOAD SENTINEL MOTOR LOAD MonITOR 2200-40

 

KAWASAKI ROBOTICS ConTROL BOARD 50999-2383R23

 

RED LION 125VAC 3A MODULAR ConTROLLER DUAL LOOP MODULE, CSPID2RM

 

KOYO 12-24V 20 DC INPUT DIRECT LOGIC 06 PLC, D0-06DR

 

AEG SCHNEIDER MODICON TSX COMPACT ANALOG OUTPUT MODULE DAU 202 6728-042.244666

 

FANUC PCB DAUGHTER BOARD A20B-2901-0080/?03C

 

YASKAWA VARISPEED 616H BRAKE UNIT CDBR-H45H EUJ006450

 

KEITHLEY ANALOG OUTPUT & DIGITAL I/O BOARD DDA-06 / PC6182

 

SIEMENS DRIVE BOARD 6RB2025-0FA01

 

MonTRONIX ConTROL BOARD TS300 REV. 6

 

ALLEN BRADLEY VERY HIGH SPEED COUNTER MODULE 1771-VHSC SER. A F/W REV. B

 

SIEMENS SIMATIC DP, ET200X, 24VDC BASIC MODULE 141-1BF12-0xB0

 

PHOENIX ConTACT INTERBUS-S BUS TERMINAL BLOCK 2754435 IBS ST 24 BK-LK

 

PIAB 0.4-0.6MPA CLASSIC VACUUM PUMP M25B6-EN *PLASTIC*

 

GE FANUC SERIES 90-30 PLC GENIUS ENHANCED COMMUNICATION MODULE IC693CMM302K

 

GE FANUC SERIES 90-30 PLC GENIUS ENHANCED COMMUNICATION MODULE IC693CMM302L

 

FANUC OPERATOR INTERFACE ConNECTION BOARD PCB A16B-2200-0660/?04A *DAMAGED #2*

 

FANUC OPERATOR INTERFACE ConNECTION BOARD PCB A16B-2200-0660/?04A *DAMAGED #1*

 

ConTROL INSTRUMENTS PRESSURE TRANSMITTER XTR031

 

MITSUBISHI ELECTRIC MELSEC NET/MINI-S3 MODULE A1SJ71T32-S3

 

SCHNEIDER MODICON DATA FORMAT 984 MB+ COMMUNICATION ADAPTER 170NEF11021 *NEW*

 

FANUC ROBOTICS REMOTE ETHERNET PCB ER1T BOARD A16B-2203-0292/?01A

 

SMARTEYE FIELD INTERFACE BOARD PCB SP1002/02 REV. B

 

WHEDCO ConTROLLER IMC-3141-2-B 78003892

 

NORDSON TEMPERATURE ConTROL MODULE 282500A

 

DAYTRonIC 105-135VAC 10W STRAIN GAGE INDICATOR/CONTR?OLLER, 3370

 

USON PROM MEMORY CARD 408-X300B

 

POWER DESIGNERS LLC ConTROL BOARD PCB-510028-00 REV. E

 

INDRAMAT ConTROL MODULE AS131/006-000

 

PILLAR CORPORATION POWER SUPPLY BOARD AB4219-2(H)

 

YASKAWA ELECTRIC BACKPLANE UNIT JZNC-MRK09-15

 

ALLEN BRADLEY 40-50HP AC DRIVE PRECHARGE KIT 140150 *NEW*

 

OMRON DIGITAL TIMER H5AN-4DM NIB

 

FANUC ROBOTICS MAIN CPU BOARD PCB A16B-3200-0040/?08D

 

FANUC ROBOTICS MAIN PROCESSOR CPU PCB A16B-3200-0040/?06D

 

RELIANCE ELECTRIC ISOLATED PROCESS ConTROL BOARD 0-56313

 

SMARTEYE DISPLAY BOARD SP1023/01 REV. B

 

SMARTEYE DISPLAY BOARD SP1023/01 REV. B

 

RELIANCE ELECTRIC DIGITAL ConTROL SYSTEM DRIVE ANALOG I/O 57405-C

 

RELIANCE ELECTRIC DIGITAL ConTROL SYSTEM DRIVE ANALOG I/O 57405-D

 

RELIANCE ELECTRIC DRIVE ANALOG I/O B/M 57405-E

 

MITSUBISHI ELECTRIC 100W 26OHM RESISTOR UNIT MR-RB14

 

HonEYWELL I/O EXPANDER MODULE 620-0053

 

CMC MOTOR ConTROLLER ACU1506-1-100-0?01 REV. -2

 

AEG MODICON 120V OUTPUT MODULE AS-B806-032 *REPAIRED*

 

MANNESMANN REXROTH ConTROL CARD SUI VTS0311-11

 

NORDSON PRO FLO COMMUNICATION BOARD 227119B

 

ALLEN BRADLEY SLC 500 13-SLOT RACK 1746-A13 SER. B W/ POWER SUPPLY 1746-P2 SER C

 

HANSEN TECHNOLOGIES FROST MASTER DEFROST ConTROLLER FM-71-A

 

ABB OPERATOR INTERFACE BOARD 3HAC 14228-2/04

 

SPANG POWER ELECTRonICS POWER ConTROL UNIT E6974

 

SQUARE D WELDING FIRING MODULE 1400621 WITH POWER SUPPLY 1400581-004

 

STI MINSAFE / FLEXSAFE LIGHT CURTAIN ConTROLLER 4300B

 

PHOENIX ConTACT 8 TP RJ45 PORT ETHERNET SWITCH FL SWITCH SF 8TX *NIB*

 

MITSUBISHI ELECTRIC MELSEC DATAlink UNIT A1SJ61BT11

 

FANUC ROBOTICS I/O BOARD PCB A20B-1006-0290/?02B

 

BALLUFF COLOR SENSOR I/O BOARD BFS 2-MU-30M-01 / BLFBFSZ1K01 *NIB*

 

BROOKS MT 3810 VARIABLE AREA FLOWMETER TRANSMITTER 3810A12C1RAA1Q1

 

BROOKS MT 3810 VARIABLE AREA FLOWMETER TRANSMITTER 3810A13D1RAA1A1

 

BROOKS MT 3810 VARIABLE AREA FLOWMETER TRANSMITTER 3810A13C1RAA1A1

 

BROOKS MT 3810 VARIABLE AREA FLOWMETER TRANSMITTER 3810A12D1RAA1S1

 

FESTO 87PSI 6 BAR MULTI VALVE ConTROL MODULE IT-IF-10/3 DC 24V *BUTTON*

 

BINKS SAMES AIR PRESSURE ConTROL MODULE 22-614 REV. B

 

BINKS SAMES AIR PRESSURE ConTROL MODULE 22-614

 

BINKS PCB P/N 22-527 REV. B

 

BINKS PCB 22-550 / 22-527 REV. B

 

BINKS PCB 22-550 REV. B / 22-527 REV. A

 

ROSEMOUNT ALPHALINE PRESSURE TRANSMITTER 1151DP4922

 

NATIonAL INSTRUMENTS SCXI-1315 TERMINAL BLOCK 186963A-01 *NIB*

 

ALLEN BRADLEY SLC 500 13 SLOT RACK 1746-A13 SER B W/ POWER SUPPLY 1746-P3 SER. A

 

TRW NELSON ConTROL BOARD NTR 1200W NTR 1800W LP-AUSG-THY VERS. B 660276 b

 

ALLIS CHALMERS SWITCHGEAR STATIC TRIP II TYPE TIG

 

ALLEN BRADLEY HANDHELD PROGRAMMER 1771HD / 91657702 *CABLE*

 

RELIANCE ELECTRIC VARIABLE SPEED AC DRIVE 2GU41002 *MODIFIED*

 

EMERSON DC DRIVE ConTROL BOARD 2600-4105 REV. E

 

PHOENIX ConTACT InterBus I/O MODULE IB STME 24 DIO 8/8/3-2A

 

COMPUTER PRODUCTS PM962 BOARD, NNB

 

OMEGA FLOW INDICATOR LR923369

 

ALLEN BRADLEY 12-24V GRAY ENCODER MODULE 1771-DL

 

RELIANCE ELECTRIC base DRIVER CIRCUIT BOARD 0-54392

 

ALLEN BRADLEY DEVICENET 24VDC FLEX I/O MODULE 1794-ADN SER. B F/W REV. J *NEW*

 

SEW EURODRIVE MQD32A 824202X.12.13 DeviceNet MODULE WITH FIELDBUS INTERFACE NIB

 

BLACKBOX IC107C-R2 RS-232 to RS-422 BiDirectional ConVERTER CARD, NIB

 

ALLEN BRADLEY 24VDC SINK INPUT / SOURCE OUTPUT MODULE 1794-IB16X0B16P SER. A