主要抗干扰措施
4.1采用性能优良的电源，抑制电网引入的干扰
在PLC控制系统中，电源占有极重要的地位。电网干扰串入PLC控制系统主要通过PLC系统的供电电源（如
电源、I/O电源等）、变送器供电电源和与PLC系统具有直接电气连接的仪表供电电源等耦合进入的。现在，对于PLC系统供电的电源，一般都采用隔离性能较好电源，而对于变送器供电的电源和PLC系统有直接电气连接的仪表的供电电源，并没受到足够的重视，虽然采取了一定的隔离措施，但普遍还不够，主要是使用的隔离变压器分布参数大，抑制干扰能力差，经电源耦合而串入共模干扰、差模干扰。所以，对于变送器和共用信号仪表供电应选择分布电容小、抑制带大（如采用多次隔离和屏蔽及漏感技术）的配电器，以减少PLC系统的干扰。
位保证电网馈点不中断，可采用在线式不间断供电电源（UPS）供电，提高供电的安全可靠性。并且UPS还具有较强的干扰隔离性能，是一种PLC控制系统的理想电源。
4.2电缆选择的敖设
为了减少动力电缆辐射电磁干扰，尤其是变频装置馈电电缆。笔者在某工程中，采用了铜带铠装屏蔽电力电缆，从而降低了动力线生产的电磁干扰，该工程投产后取得了满意的效果。
不同类型的信号分别由不同电缆传输，信号电缆应按传输信号种类分层敖设，严禁用同一电缆的不同导线同时传送动力电源和信号，避免信号线与动力电缆靠近平行敖设，以减少电磁干扰。
4.3硬件滤波及软件抗如果措施
信号在接入计算机前，在信号线与地间并接电容，以减少共模干扰；在信号两极间加装滤波器可减少差模干扰。
GE Limitamp Multilin Starter 2000 HP
4160V CR7160C118G
Gould ITE Breaker S SD SD3B250D0000A 2500
Amp A 2500Amp
Fincor 3166S7003A 738 KVA 480V DC Drive
700 HP H P
MGM 2000 kVA 13200 4160 Y / 2400 Padmount
Transformer
Ingersoll Rand Centac 2C40M4 1973 Reb.
11,000 hrs
Allen Bradley AB 1336S-B250-AN-EN4-L6 250
HP VS Drive
Benshaw CBRSM6-600-480-12 720A 3PH 480V
AC Drive 600 HP
Square D Transformer 2500/3333 kVA
12470/7200 480/277
Elliott Turbocharger Turbo Blower L-402
1L1 KVS Rebuilt
Allen Bradley AB 1336S-BX250-AX-EN4-L6
250/300 HP Drive
ABB MEGAMAX SACE F4S F4S3200 F4 3200 Amp
3200A 690V
Square D 2500 Amp 2500A SED362500LSGES5D4
SED362500LSG
APV Invensys Plate Frame Heat Exchanger
R5 621 sq ft SS
Westinghouse Advantage W201KHCF Sz. 6
Reverse Contactor
Western Gear Increaser 4113-IHS High
Speed Unit 9000 HP
Square D QED 4x NEF Breaker Panel 4000
Amp A 4W Ground
Square D NE NEF361200LSG 1200 Amp 1200A A
LSIG
Square D NE NEF361200LSG 1200 Amp 1200A A
LSIG
GE AKR-10D-125 5000 A Amp Breaker MVT
Plus Trip 635 V
ASCO 1200 Amp G9623120097XC Transfer
Switch 480/277 4W
Square D Enclosed 48 Soft Start Altistart
8839 400 HP H
Square D QED Breaker Panel 2x PEF361600LS
1600 Amp A 4W
Square D NE NEF36800LSG 800 Amp 800A A
LSIG
Square D Masterpact Breaker MP25H1 2500
Amp 2500A A
Grate Wash Pump Control Panel Starter
Helix 400A 480V
Cutler Hammer CH Advantage W240M6CFC Sz
Size 6 MCCB
Square D New EZ Meter Pak EZM11600CB 3R
Meter Center
Bell Gossett Plate Frame Heat Exchanger
GPX 807 1057 sq
NWL Transformer 260 kVA 460 500/24000
27000 260kVA oil
Square D QED BPO364 Bolt Loc Switch Panel
4000 Amp A 4W
Toshiba VFAS14132KPCA1 Inverter VF-AS1 VS
Drive 200 HP
Square D QED 2x NEF Breaker Panel 4000
Amp A 4W Ground
Cutler Hammer CH Advantage W240M6CFC Size
Sz 6 Starter
Fanuc A06B-6105-H002 6 Axis Servo
Amplifier REM
GE Limitamp Multilin Starter 1250 HP 4160
V CR7160B118G
ITE GOULD BBC ABB K3000 K 3000 3000A Air
Breaker LS
Square D QED Breaker Panel PXF361000LSI
1200 Amp A 4W
Cutler Hammer CH Advantage W240M6CFC Size
Sz 6 Starter
Graco Magna Drum Pump Premier 800 Air
222-800 C59792
Cutler Hammer CRD CRD316T33W 1600A
1600Amp 1600 A
Digitrip 310 TRIP UNIT RES1600LS W/AUX
AND SHUNT TRIPS
Cutler-Hammer Magnum DS MDS630 3000 Amp
Digitrip 520 A
Yaskawa CACR-UP130AAB Robot Servo Unit
CACRUP130AAB
Allen Bradley AB 1336S-B200-AN-EN-L6
200/250 HP V Drive
Toshiba Vacuum Contactor YDCT Motor
Starter 600 HP 460V
Square D Schneider Masterpact NW12L 1200
Amp 1200A NIB
Westinghouse A200M6CXZ2DX Size 6 A200M6C
Motor Starter
Onan 1200 A Amp Bypass Transfer Switch
ATS 480V BT 1200
Cutler Hammer CRD CRD320T33W 2000A
2000Amp 2000 A
Digitrip 310 TRIP UNIT RES2000LS W/AUX
AND SHUNT TRIPS
Westinghouse PC 2000 Amp 2000A A PC32000
2000A Trip
Square D QED I-Line SwitchBoard 5000 Amp
3000A 480Y/277
Cutler-Hammer Magnum SB SBSC12 1200 Amp A
Digitrip 520
Hitran Transformer 870 kVA 460/460Y/266 V
3PH Y 870kVA
Siemens 6SE7232-6EG00-3AB0-Z VT VF 200 HP
VS AC Drive
Yaskawa CACR-UP130AAB Robot Servo Unit
CACRUP130AAB
Cutler Hammer CH Advantage W201KHCF Size
6 Contactor
Siemens Breaker Enclosure Panel FC 1 FCI
2000 Amp A 4W
GE AKR-10D-100 4000 A Amp Breaker MVT
Plus Trip 635 V
Allen Bradley AB 1336F-B075-AA-EN 75 HP
480V NIB New
Sew Eurodrive R143DV 7HP Ratio:107.25
Gear Reducer REM
Square D 3R QED I-Line Panelboard 1600
Amp 480Y/277 V
Tranter Superchanger Plate Frame Heat
Exchanger 06T26UP
Square D QED I-Line PanelBoard 4000 Amp
3000A 480Y/277
Cutler-Hammer Magnum DS MDSC5N 2500 Amp
Digitrip 520M