Insight of Mechanical and Electrical Components used PLC Programming

What is PLC Programming?

A PLC (Programmable Logic Controller) is an industrial computer control system. It provides the brainpower necessary to allow the machine to operate using coding logic programmed into the PLC.

Widely used in manufacture and automation, PLC Programming is the digital logic running in the background of a machine unseen to the operator. This logic is designed and programmed in a manner that provides the machine with actuation, monitoring and control and overall safety of a certain process or operation. In fact, the machine is required to accomplish. Using a combination of inputs and outputs with PLC logic, we can program a machine controller to move actuators. Simultaneously, we use sensors that would fold the edges of a box together to form the basic shape of the box and then add tape to the seams of the box also using some type of actuator. Essentially the code in the PLC is allowing a machine to operate within the guidelines that the controls programmer specifies.

What does a PLC Programmer do?

A PLC programmer is responsible for providing a machine’s controller with logic that allows the machine to function in the most efficient manner as possible. The programmer is also responsible for providing easy code to understand and modify in the case that a modification has to be made in the future by someone who did not create the original program.

Complementing the PLC program, a programmer also integrate components on the machine using the different protocols that the PLC can support. These pieces of hardware/software can range from:

• remote I/O blocks
• vision cameras
• barcode readers
• servo motors
• sensors
• pneumatic valve banks
• HMIs (Human Machine Interface – touchscreen interfaces) to robots and PCs.

The main goal is to allow all of the components in a machine to report back to the PLC so that the PLC can use the logic programmed into the unit to complete the desired outcome.

What is PLC Ladder Logic?

Plc programming differs from computer programming logic in the sense that most PLC logic is programmed using ladder logic, while computer programming uses text-based programming such as “C, C+ languages. The commands can be mapped out in a simple and easy to understand manner such that a technician can understand what needs to happen before another action is made possible.

The PLC logic can be viewed using PC software that allows the controls programmer to view and modify the logic, in most cases in real-time as the plc machine is operating. This helps the controls programmer understand what is happening and troubleshoot any issues that may appear after the offline code is written.

Where is PLC Programming used?

PLC programming is used in industrial applications.  They are often used to control equipment used in manufacturing.

Some of the industries that use PLC programming are:

• Manufacturing
• Food / Beverage
• Textile
• Travel
• Aerospace
• Printing
• Automotive
• Medical

What is PLC programming process?

A PLC programmer ensures that a machine’s controller is properly functional using code developed by the controls department. This allows a machine to complete the process  designed for. As can be seen, this is an OMRON modular PLC and Safety PLC using several different communication methods to operate the machine. The PLC below used an RS-232 interface to communicate to an outside piece of hardware marking a part. DeviceNET is to communicate to Inputs and Outputs located outside of the main control panel and Ethernet communication. All is to allow the PLC to communicate with barcode readers, servos and the Safety PLC. The PLC programmer uses all of their combined training to allow all of these devices to communicate with the brain of the system, the PLC. Below is an image of the above-described layout:

What types of projects does a PLC programmer get to work on?

A PLC programmer can work on jobs that include anything from basic sensors to complex robots. Although a programmer may not do all of the programming required in the outside peripheral devices, theycan make sure all of those components communicate properly with the PLC in a manner that controls them based on the requirements of the process. This usually includes job specific training and previous experience combined to allow the programmer to complete the task at hand. A programmer should expect to work on jobs that include different PLCs and software from different manufacturers. A project that a PLC programmer could work on and include, but not limited to, presses, hydraulic and pneumatic, assembly stations, robotic welding/assembly, vision inspection, and machining applications.

What jobs are available for a control system programmer?

Available jobs for a control systems programmer include:

• Offline PLC and HMI programming
• Robotic programming
• Servo programming
• SCADA (Supervisory control and data acquisition) system programming
• Machine development

A controls programmer could work in the local programming machines, getting them ready for run-off and install to troubleshooting existing jobs on site. Some are versed in writing code from the ground up and organizing large scale projects. Others do service call work to retrofit existing systems currently running in a customer’s plant. The best control systems programmers are those who are experienced in multiple software platforms and communication protocols combined with a good knowledge of hardware application and usage.

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