描述
除了I/O映象区以外，系统RAM存储区还包括PLC内部各类软设备（逻辑线圈、数据寄存器、计时器、计数器、变址寄存器、累加器等）的存储区。该存储区又分为具有失电保持的存储区域和无失电保持的存储区域，前者在PLC断电时，由内部的锂电子供电。使这部分存储单元内的数据得以保留；后者当PLC停止运行时，将这部分存储单元内的数据全部置“零”。
MINT Modicon AS-B885-002 ASB885002 Basic Module
MYCOM UPS50-031 UPS50031 Stepper Drive
NEW SEALED Allen Bradley 1786-TPYR /B 1786TPYR
NEW Allen Bradley 1791-32B0 /B 179132B0
NEW Rexroth R-165-121-420 R165121420 Runner Block
NEW Allen Bradley 194E-NX48 /A 194ENX48 Load Switch
Reliance Electric 0-52808-2 0528082 CLVC Board
New United Electric E105-3BS 9027 E1053BS9027 Temp SW
NEW Allen Bradley 1794-IA8 /A 1794IA8 Input Module
NEW Allen Bradley 800H-JR91KE7AAXX /F 800HJR91KE7AAXX
NEW Allen Bradley 1792D-2BV0D /A 1792D2BV0D
NEW SEALED Allen Bradley 20-VB00601 20VB00601
NEW DURANT Electric Counter 6-Y-1-RMF 6Y1RMF
NEW Allen Bradley 100-M09N*3 /A 100-M09 Contactor
