CPU Units CPU Units The four models of CPU Units can be broadly divided into two groups: Models that support Inner Boards and the Controller Link Unit, and models that do not. The CPU Units also vary in their program capacities, I/O capacities, memory capacities, and the presence of an RS-232C port, as shown in the Basic Specifications table, below. CPU Unit Overview The following illustration shows the main components of a CQM1H-CPU61 CPU Unit. Sliders Used to secure adjacent Units. Battery Compartment Cover Open this cover to access the battery, DIP switch, and Memory Cassette. Connector Add on Units horizontally by joining connectors. LED indicators Peripheral Port Used to connect to Programming Devices such as a Programming Console or a computer running CX-Programmer. Also supports Host Link and no-protocol communications. Built-in Inputs There are 16 inputs built into CPU Unit. Inner Board Covers Remove these covers when installing or removing Inner Boards. RS-232C Port (except CQM1H-CPU11) Used for Host Link, no-protocol, 1:1 Data Link, or NT link (1:1 mode) communications with external devices or other PLCs. Inner Board Slot 2 (right slot) Use this slot to mount a High-speed Counter Board, Pulse I/O Board, Absolute Encoder Interface Board, Analog Setting Board, or Analog I/O Board. Inner Board Slot 1 (left slot) Use this slot to mount a High-speed Counter Board, Analog Setting Board, or Serial Communications Board. Basic Specifications Model CQM1H-CPU61 CQM1H-CPU51 CQM1H-CPU21 CQM1H-CPU11 I/O Program capacity capacity (See note.) (words) DM capacity (words) EM capacity (words) 512 6K 6K 3K 6K None 256 15.2 K 7.2 K 3.2 K Built-in serial ports CPU Unit built-in Peripheral RS-232C port port inputs DC: 16 Yes Yes No Maximum Number of Units CQM1H-CPU61 CQM1H-CPU51 CQM1H-CPU21 CQM1H-CPU11 10 Controller Link Unit Inner Boards 1 max. 2 max. Not supported. Not supported. Controller Link Unit Supported Not supported Note: I/O capacity = Number of input points ( 256) + Number of output points ( 256). CPU Unit Inner Boards I/O Units and Dedicated I/O Units 11 max. ((total))