描述
在PLC控制系统的故障中，CPU占5%，I/O接口占15%，输入设备占45%，输出设备占30%，线路占5%。前二项共20%故障属于PLC的内部故障，它可通过PLC本身的软、硬件实现检测、处理；而其余80%的故障属于PLC的外部故障。因此，PLC生产厂家都致力于研制、发展用于检测外部故障的专用智能模块，进一步提高系统的可靠性。
JUNIPER RE-600-2048-S T640 ROUTING ENGINE RE-600-2048
One-day shipping available
*NEW* Juniper EX2200-24P-4G EX2200-24P-4G Ethernet
Juniper T320-FPC3-E T320 Router Enhanced FPC
90 Day Warranty – Free Shipping
Juniper PB-4CHDS3-QPP 4 Port PB 4CH DS3 to DS0 IQ
1 YR WRNTY w/ Tech Support. Will Ship Int’l VER 1.12
One-day shipping available
Juniper PB-1OC12-SON-SMIR PIC for M160/M40e Warranty
Juniper Networks RE-400-768 Routing Engine Board RE-400
Juniper M10BASE-AC M10 chassis w/RE-333-768 AC Power
Juniper SSG-520M-SH SSG 520 Secure Services Gateway GF
SSG-520M-SH Secure Service Gateway (used) Juniper Base
Juniper SA2000 Secure Access VPN Appliance GF
Multiple Licenses Installed
