RAM存储器中的数据将丢失，因此当PLC断电时为防止RAM中的数据丢失必须使用备用电池.非易失存储器-当供电电源断电后存储器中的内容将保留。各种不同类型的PROM (可编程只读存储器)的数据不会丢失.A存储器每一种类型的系列90-30 CPU为其“工作数据存储”都使用了RAM存储器，RAM芯片使用的是CMOS类型。

ALLEN BRADLEY 1771-HT3, 700-HN15 TERMINATION PANEL W/ R

MORSE R 180 60 AY1553 XX5289 GEAR REDUCER, NIB

TPC WIRE & CABLE 66312 TREX-ONICS 19P M/F, APPR. 50′, L

TURCK NI20-CP40-VP4X2?-H1141 10-65VDC 200mA SENSOR,

RELIANCE ELECTRIC DIGITAL CONTROL SYSTEM CARD FIELD REG

UNITED ELECTRIC / RWM J6-142-1521 PRESSURE SWITCH, NNB

ALLEN BRADLEY 1771-HM34 64KW CMOS MEMORY MODULE

ALLEN BRADLEY POWER SUPPLY MODULE 5120-P1/A 960452-75 S

RELIANCE ELECTRIC DISTRIBUTED CONTROL SYSTEM RESOLVER I

SQUARE D 9423 TYPE M-8 VAULT HANDLE DOOR CLOSING MECHAN

THOMSON SUPER 20 OPN LINEAR BEARING, NIB

ALLEN BRADLEY 800MR-QTL24GK FULL VOLT 24V SERIES D SMAL

TEST PRODUCTS MAA157726S CONNECTOR, NNB

THOMSON SUPER 20 OPN LINEAR BEARING, NNB

RELIANCE ELECTRIC DIGITAL CONTROL SYSTEM CARD 57401-C

RELIANCE ELECTRIC DISTRIBUTED CONTROL SYSTEM CARD DR DI

TURCK BI15-EM30H-AP6X?-H1141/S1589 10-30 VDC INDUCTIVE S