描述
为使PLC能可靠工作,在硬件与软件两个方面PLC厂家都采取了很多措施,对一些特殊可靠要求的PLC,还有相应的特殊的措施,如热备、冗余等等。这在介绍PLC的特点时已作了叙述。可靠措施的目的是增加PLC平均故障间隔时间、MTBF(MeanTimeBetweenFailure)及减少PLC的平均修复时间、MTTR(MeanTimeToRepair),以提高PLC的有效度A(Availability)。
Hard Drive SCSI IBM DNES-309170 25L1910 F42003 E182115
Hard Drive SCSI IBM 79F4022 C72756 56F8854 WDS-380S DH
Hard Drive SCSI Seagate Cheetah ST136403LW 9L7005-001
Hard Drive SCSI IBM PN55F9902 55F9916 EC844857 012587
Hard Drive SCSI Rodime RO3259T E1 S36423862 12007730
Hard Drive SCSI Disk MiniScribe 8425S C493571 G03-88
Hard Drive SCSI Hewlett Packard DPSS-318350 07N5277 HP
Hard Drive SCSI Seagate Cheetah ST336706LC 9T9001-001
Hard Drive SCSI IBM Ultrastar IC35L009VWD210-0 07N6360
Hard Drive SCSI Seagate Barracuda ST318437LW 9U2002-001