步骤如下：
（一） 将Ｓ7-200（以226为例）的RS485通信接口和4个S7-EM239 的RS485通信接口用双绞线串接起来，Ｓ7-200通信口（九芯）的３脚接4个S7-EM239通讯口的3端子（A+）；Ｓ7-200通信口（九芯）的8脚接4个S7-EM239通讯口的8端子（B-）；Ｓ7-200通信口（九芯）的5脚接4个S7-EM239通讯口的1、9端子（485地）。
（二） 在Ｓ7-200安装MODBUS协议库，调用MBUS_CTRL设置S7-200的通讯参数（19200bps），调用MBUS_MSG读取4个S7-EM239模块的采集数据。
就是这么简单。此种方法最多可采集512路模拟量或1024路开关量(32个站时)，还可以用于控制多路模拟量或开关量输出。NEW HUB CITY A 7/8 BEARING
NEW FAFNIR BALL BEARING 204KL 204KD 204KL
NEW INA KR26PPX CAM FOLLOWER KR 26 PPX
INA NK 25/20 NK25/20 NK 25-20 NEEDLE BEARING NEW
NEW NSK ROLLER BEARING R20ZZ
NEW MCGILL MO18N NEEDLE BEARING
NEW MCGILL MR18N NEEDLE BEARING
McGill Inner Race Bearing MI 15 MI15 New
MRC TRW BALL BEARING 209SF NIB
MRC Bearing 108KSZZ H501 New
Andrews Thrust Ball Bearing GT-10 GT10 New
NEW NICE BEARING 1633 DC TN 1633DCTN
NEW NTN ROLLER BEARING 6210
Fafnir Pillow Block Bearing w/ Collar RAKH 1 7/16 RAKH1716 1-7/16" Bore New
NEW INA END HUB BEARING GE 35 KRRB GE35KRRB RHE 35
AMI ASAHI UG208-24 PILLOW BLOCK BEARING NEW
Torrington Needle Bearing 10-7245 107245 10 7245 NEW
NEW SKF BEARING 6205 JC3 6205/C3 6205
NEW SKF SEALED BALL BEARING 6305-2Z/C3 63052Z/C3 63052ZC3
NEW TORRINGTON HJ-223020 HJ223020 NEEDLE ROLLR BEARING MS-51961-19
New Airfloat High Performance Air Bearing H-0010-F H0010F 10" OD 1/2" ID New
NEW REXNORD ADAPTER H320055
NEW TDL BEARING 6200RSL C3 6200RSLC3
MRC Single Row Sealed Ball Bearing 105KSZZG New
NEW NDH BEARING 1304TS
NEW GMN BALL BEARING 16004
MRC Single Row Ball Bearing 38FF10 New
Torrington IR Bearing STO12ZZ New
3 Fafnir CB14A roller conveyor Bearing pentagon id new
LOT OF 3 NEW NO NAME TAPERED ROLLER BEARING L44643
NEW TIMKEN FAFNIR VAK 3/4 BALL BEARING PILLOW BLOCK HOUSED UNIT
NEW FAG ADAPTER SLEEVE H 206 H206 "LOT OF 3"
MRC Bearing 105KSZZ New
NEW IKO DOUBLE SEALED BEARING SBB8
FAFNIR BEARING 202KD NIB
NEW MCGILL CAM YOKE ROLLER CYR 1-1/2 CYR1-1/2
NEW TSK INSERT BEARING 76160LG "LOT OF 2"
INA GT24 Thrust Bearing GT-24 New
Steyr Thrust Bearing 51206X New
NEW NACHI ROLLER BEARING 6206NS
SKF Tapered Roller Bearing 3979 New
NEW NACHI BEARING R12NSL
NEW FAFNIR BEARING S8PP
SKF Bearing 6205 New No Box
NEW KYK BEARING 6203ZZNRC3
RBC CAM FOLLOWER S 24 S S24S NIB
NEW NTN BEARING R16 R16L
NEW L&S BEARING S19 07100
Bower Tapered Roller Bearing 582 New
NEW TYSON TAPERED ROLLER BEARING 07097
NEW MCGILL CAM ROLLER CYR-1 CYR1
NEW SNR BEARING 6207 J30 6207J30
NSK 6211-DU Ball Bearing 6211DU 55mm Bore
NEW RBI BEARING 1541-DS 1541DS
NEW KOYO BEARING 6201ZC3
NEW Torrington CAM Follower Bearing CRS-20-M CRS20M
NEW CONSOLIDATED / JAF RA-208 INSERT BEARING W/ COLLAR CONS RA-208 RA208
NEW INA NEEDLE ROLLER BEARING SCE85
Torrington Sealed Cam Yok Roller Bearing YCRSC-32 YCRSC32 New
NEW SKF ANGULAR CONTACT BEARING 7011 CP4DGA 7011CP4DGA 7011C/P4 DGA
NEW ENDURO BEARING 30209
Fag Bearing 6210 T P/5 6210.P5 6210P5 New
NEW TIMKEN TAPERED BEARING RACE 47620
NEW DODGE FLANGE BEARING SC 1-7/16
New NBR Flange Bearing With NO Collar HC208-24 HC20824 FS208
New Fafnir Shielded Bearing 5207WD
NEW THOMSON BALL BUSHING LINEAR BEARING OPN243848
SKF 1207KTN9 Self Aligning Ball Bearing 1207-KTN9 New
NEW HYATT NEEDLE BEARING 7147
Torrington Bearing NKJ12/16A NKJ1216A NK16/16A NK1616A New
HYATT PRECISION BALL & ROLLER BEARING 5202 NIB
NEW FAFNIR BEARING 304PP
NEW CONSOLIDATED THRUST BALL BEARING D-11 D11
AMI Ball Bearing Insert With Collar KH205-16 KH20516 New
NTN Single Row Radial Ball Bearing 6200LLB 6200LLB/5C New
FAG Self Aligning Ball Bearing 223/2310 2232310 New
NEW NSK SINGLE ROW BALL BEARING 6208
NEW FAG 6208.C3 BALL BEARING 6208C3
NEW NKE SINGLE ROW BALL BEARING 6202-2RS2-C3 6202RS2 62022RS2C3
Conveyor Roller Bearing MRK-80x2/6204 6204Z 3"OD Lot 4
NEW NTN BALL BEARING 60052C3 6005ZZC3/L627 6005ZZC3L627
NEW TIMKEN BEARING OUTER RACE 472D INNER RACE NA484
SKF Self Aligning Roller Ball Bearing 22217CCK C3 22217CCKC3 New
MRC Rubber Sealed Ball Bearing 207SZZX H501 made in Spain New
HYATT / SRB A1216 Bearing Race A1216 New
NEW KBC 6301Z BEARING 6301ZZC3G14
AMI Asahi Pillow Block Bearing MUC205FD MUC205-16 MUC20516 New
MRC TRW BALL BEARING 208SG NIB
NEW SKF BEARING 7205 BECBY 7205BECBY
NEW TIMKEN TAPERED ROLLER BEARING WITH OUTER RACE 30204 9-2850
INA Needle Roller Bearing NA 6904 NA6904 New
NEW DEPARTURE HYATT BEARING Z993L09
NEW CARQUEST TAPERED ROLLER BEARING 07204 4T-07204 4T07204
NEW RHP BEARING KLNJ1 3/8 KLNJ138
New AMI 2 Bolt Flange Bearing KHPFL204
NEW DODGE FLANGE BEARING LFSC100NL 124625
Federal Mogul Bower Tapered Roller Bearing 3782 New
NEW NICE BEARING 1616 DS TNTG18 1616DSTNTG18
NEW NTN BEARING 629LLB/2A 629LLB2A 629LB
SKF ADAPTER SLEEVE H 206 H206
NEW Fafnir Mounted Ball Bearing 205KDD11 205 KDD 11
NEW REXNORD ROLLER CARTRIDGE BEARING 5115
NEW KOYO ANGULAR CONTACT BALL BEARING 7208BGC3
SKF Angular Contact Bearing 7308 BECBY 7308BECBY New
NEW SNR 6211.EEJ30 DEEP GROOVE BEARING 6211J30
No Name Steel 4-Bolt 1-1/2" NPT Flange w. Hardware New
SKF ROLLER BEARING 6004-2Z/C3GJN 60042ZC3GJN NEW
IKO CAM FOLLOWER CR 26UU CR26UU NIB
REXNORD 2 BOLT PILLOW BLOCK C251 0811 NIB
NEW SKF ROLLER BEARING 7303BEP
NEW SKF BEARING 6301-2ZJEM 63012ZJEM
KBC 6200DDC3G14 Bearing 6200DDC3G14 New
NEW PEER BEARING 77R16 5664 77R165664
MRC R8FF BEARING R8-FF R8FF M31 H503 NEW
McGill Cam Follower Camfollower CFE 5/8 SB CFE58SB New
INA Cam Follower Camfollower Bearing CF12SK CF12 3/4" New
NEW MRC ROLLER BALL BEARING 38FF10 H001 38FF10H001
NEW SEALMASTER BEARING 720953 15/16" SK-1471 W/ COLLAR
RHP SELF-LUBE FLANGE BEARING SFT-25 SFT-3 1025 25 G NEW
PTI Shielded Roller Ball Bearing 1652 Z 1652Z Lot of 2 New
Torrington Inner Race Bearing IR-081212 IR081212 MS-51962-2 MS519622 New
NEW SMITH CAM ROLLER BEARING YR-1 1/4 YR-11/4 YR11/4 YR114
NTN Tapered Roller Bearing 4T-15125 4FL29 NEW
NEW URB ROLLER BALL BEARING 1310
NEW BL BEARING S6203 RS S6203RS
NEW INA IR25X30X20.5 BEARING IR25X30X205
NEW NSK SINGLE ROW RADIAL BALL BEARING 6206VVC3 6206V
SKF Self Aligning Double Row Ball Bearing 1215 KJ 1215KJ 1215K 75X130X25MM New
NEW MRC TRW BEARING 5206 SBKFF 5206SBKFF ABEC1 5206SBKFFABEC1
NEW BROWNING adjustable V-BELT PULLEY 1VM50-5/8 1VM505/8
NEW FAG SPHERICAL BEARING 22206ES
NEW RHP INSERT BEARING 1035-1 3/16G 10351316G
MRC 310S ROLLER BEARING NEW
NEW SKF BEARING 30206J2
NEW FAFNIR BEARING 304K
Fafnir Ball Bearing 9105KDD 9105KDD C2 9105KDDC2 New
INA Needle Roller Bearing NCS 1412 A NCS1412A New
Dodge Pillow Block S/S Stainless Steel Bearing P2BSCEZ100SHSS New
(2) Torrington Cam Follower Camfollower Bearing CR-14 CR14 7/8" New Lot of Two
NEW NICE 1633 DCTN BEARING 1633 1633DCTN
NEW BROWNING BEARING LS-116 LS116
TRW MRC 202SFF4 (0019) BEARING NEW
FAG 21315E SPHERICAL ROLLER BEARING PARALLEL BORE NIB
NEW FAFNIR BEARING KSP10 FS 428 KSP10 FS428 KSP10FS428
NEW GBC GENERAL BEARING CORP. BALL BEARING 21507-88-300 2150788300 16070C ON PKG
MRC Single Groove Radial Ball Bearing 309S New
NEW NSK 1202 SELF ALIGNING BALL BEARING
INA Needle Bearing HK 2212 HK2212 New
NEW TYSON TAPERED ROLLER BEARING 07100
Hoover S-3604 Ball Bearing S3604 New
NEW NTN NEEDLE BEARING RNAO-10x22x10x RNAO10x22x10x
NDH Double Row Ball Bearing 1 # 55502 55502 5202 New
Farfnir Torrington Insert Bearing w/ Collar GRA100RRB+COL GRA100RRB New
BARDEN PRECISION BEARING SFR4SS3 SFR4SS G-2 G2 T 23 U T23U NIB
NEW SKF 6309-2Z/C3HT51 BEARING 6309-2ZJEM
NEW NDH 1211TS 1211 TS 1211-TS CYLINDRICAL ROLLER BEARING
NEW CONTINENTAL WEST BI-DIRECTIONAL PRECISION BEARING 1/CW 48 1/CW48 1CW48 OPN
NEW NSK 6007N BEARING 25Z986D7
NEW SKF BEARING 62201-2RS1/C3 622012RS1C3
NEW GENERAL BEARING ROLLER BEARING 23261-88-300 2326188300 3038DC
Westinghouse Heater 966472 AH1.5 New
ICM 3PH Voltage Monitor ICM450 190-630 VAC Used
NEW FAFNIR BEARING 9109KG
NEW SMT BEARING SR-20 SR20
MRC Double Row Ball Bearing 5209M Made in USA 45X85MM New
NEW TORRINGTON / INGERSOLL RAND NTA-815 THRUST BEARING NTA815
NTN Bearing 526207U
NEW SKF ADAPTER H305
FEDERAL MOGUL 15243 BEARING NEW
NEW CONSOLIDATED PRECISION BEARING 95432
Consolidated Cam Follower Bearing CRSB-14 CRSB14 New
NEW RCBD BEARING 62072RSC3
NEW KILLIAN BEARING F350-13 F35013
NEW TIMKEN FAFNIR BEARING 204PP P204PP
NEW TIMKEN OUTER RACE BEARING 43312
NEW NKB BALL BEARING INSERT UC 204-20MM UC20420MM UC204
NEW HLU PILLOW BLOCK BEARING NAPL204-12 NAPL20412 NA204-12 NA20412
NEW SNR BEARING 6007.ZZJ30D43A50 6007J30D43 6007ZZJ30D43A50
HBC Rubber Sealed Ball Bearing S60112RS S6011RS New
SKF Ringcamf Cam Follower IR 25X32X22 IR25X32X22 New
Timken Tapered Roller Bearing Cup and Cone 3720 3778-MM 3778MM New
Fafnir G1014KRRB + COL AG Farm Bearing W/ Collar New
NEW IBI PILLOW BLOCK BEARING HCAK204-12 NA204-12U
Link-Belt Insert Bearing U 215 D U215D 15/16" Bore New
NEW NO NAME LAU1/2 INTERCHANGABLE HUB BORE 1/4" BORE
FAFNIR BALL BEARING S10P S10P C3 S10PC3 NIB
NEW AMI BEARING UCC202
SealMaster Insert Bearing SL-10 SL10 New
NEW MRC BEARING 202FS5
NEW DODGE LFTSC100 MOD FLANGE BEARING SIZE 1" BORE SC 1-205 LFTSC100
PEER Flange Bearing UCFT201-8 UCFT2018 New
Browning 4020 X 5/8 Sprocket 4020-5/8 4020 5/8 New