Li354 plc lects 2011aEnhmandah HemeeleeThis document provides an overview of programmable logic controllers (PLCs). It begins with a brief history of PLCs, noting they were developed in the 1970s as an alternative to hard-wired control systems. The document then discusses different types of control systems that preceded PLCs, including manual, relay-based, and electronic controls. It proceeds to explain key aspects of PLCs such as hardware components, characteristics, functions, operation, programming, applications, and advantages/disadvantages over other control systems. In particular, it outlines how PLCs can be programmed to perform logic, analog, closed-loop, counting, timing, and network communication functions to automate industrial processes.
111 120Enhmandah HemeeleeThis document describes an example of a programmable logic controller (PLC) system for controlling the lights in a parking lot. The PLC counts the number of cars entering and exiting the parking lot using infrared sensors. It sends a signal to an electronic sign when the parking lot reaches its capacity of 5 cars to indicate it is full. The PLC program is designed to open the entrance and exit gates using additional infrared sensors activated by remote control. Inputs and outputs are assigned addresses and the hardware is wired accordingly between the PLC and sensors/sign.
101 110Enhmandah HemeeleeThis document describes an automatic garden watering system. It uses sensors to monitor humidity and temperature, and sprinklers to water different areas sequentially. Grass is watered for 4 seconds, then flowers for 10 seconds, then trees for 18 seconds, with 10 ms timers to control each section. The system ensures adequate watering of the entire garden based on environmental conditions.
91 100Enhmandah HemeeleeThis document provides information about programming and testing PLC programs. It discusses the hardware and software needed to program a PLC, including the PLC itself, a programming device like a PC, programming software, and a connector cable. It also describes how to test a program by downloading it from the PC to the PLC CPU and using an input simulator to simulate field inputs and observe the resulting outputs. The document includes examples of ladder logic programs using inputs, outputs, AND and OR logic, and timers to control gates at a parking lot entrance and exit.
81 90Enhmandah HemeeleeThis document describes different types of memory used in programmable logic controllers (PLCs). It discusses process-image input and output registers used to transfer data between the PLC and external devices. It also describes variable memory for storing data, sequence control relays for organizing machine operations, and special memory bits for communicating information. Local memory is provided for scratchpad use or passing parameters. Analog inputs convert real-world values to digital values, while analog outputs convert digital values back to proportional currents or voltages. The document concludes by explaining how to convert a relay-based logic diagram into a ladder logic program for a PLC using basic logic elements and their addressing.
61 70Enhmandah HemeeleeThe document discusses starting a motor using a PLC and different timer instructions for PLCs. It describes hard-wired direct-on-line starting using contactors and overload protection. It then explains how to start and stop a motor using input and output connections to a PLC, including on-delay, retentive on-delay, and off-delay timer instructions. On-delay and retentive on-delay timers count time when an enabling input is on and turn their timer bit on when the current time exceeds the preset time. The retentive on-delay timer maintains its current value while the on-delay timer resets its value when the input turns off.
51 60Enhmandah HemeeleeThe document discusses several companies that manufacture PLC systems including Siemens, Allen Bradley, Omron, and Schneider. It then provides information about the S7-200 PLC including its configuration of inputs, outputs, and I/O numbering. Finally, it describes different types of instructions for PLCs including standard, special, and high speed instructions as well as examples of input instructions like bit logic instructions.
Bd1 gantumur mon e 1Enhmandah HemeeleeThe document provides specifications for a program to control traffic light signals in response to a pushbutton. The signals are to initially flicker red at one-second intervals. When the pushbutton is pressed, an indicator will light for 5 seconds during which the red signal continues flickering. Then the signals will change as follows: red flickers for 5 more seconds, yellow lights for 5 seconds, green lights for 10 seconds, then returns to the initial red flickering. The document provides tips for writing the program in a ladder logic format and testing the control operations.