早期的 PLC 一般称为可编程逻辑控制器。这时的 PLC 多少有点继电器控制装置的替代物的含义，其主要功能只是执行原先由继电器完成的顺序控制，定时等。它在硬件上以准计算机的形式出现，在 I/O 接口电路上作了改进以适应工业控制现场的要求。

ATLAS COPCO CONTROLS MACS I/O CONTROLLER BOARD 4240 500

ALLEN BRADLEY MINI-PLC-2/17 PROCESSOR W/ POWER SUPPLY 1

SQUARE D 1000VA 230/460V TO 115V STEP-DOWN TRANSFORMER

ATLAS COPCO MACS FLOPPY DISK MODULE /A 4240 5001 00

FANUC ROBOTICS CONTROL RELAY BOARD PCB A16B-1310-0601/?0

DAYKIN ELECTRIC 24V 25A DC POWER SUPPLY PSD4862425-1

STI SCIENTIFIC TECHNOLOGIES MC3 MAT CONTROLLER 43767-00

CINCINNATI MILACRON MEM3 BOARD 3-533-0242G

ALLEN BRADLEY 110-115/120V COIL 4NO CONTACTS CONTROL RE

WIPOTEC ZERBOX LV 26110378

PROMESS CONTROL CARD EPR TYPE 12008

AIR MONITOR CORPORATION MASS-tron II MASS FLOW TRANSMIT

AIR MONITOR CORPORATION MASS-tron II MASS FLOW TRANSMIT

ACCU-TRAC 1 MODEL 5100C READER UE5100D-10

ACCU-TRAC 2 MODEL 5150B EMITTER UE5150B-2

DAYKIN 1000VA 480V TO 120V STEP-DOWN DISCONNECT TRANSFO

CINCINNATI MILACRON CONTROL BOARD 3-531-4084A