In many engineering projects, it's common to face situations where the control system has too many signals, but the PLC input points are limited, which often leads to additional hardware costs. The challenge is how to maximize the use of existing equipment to handle as many data points as possible. This is a practical issue that requires careful consideration and creative solutions. Pp-Pe Film Pelletizing Line,Pelletizing Line For Pp-Pe Film,Pp-Pe Film Recycling Machine, Film Granulator For Pp-Pe Zhejiang IET Intelligent Equipment Manufacturing Co.,Ltd , https://www.ietmachinery.com
One effective way to reduce the number of required input points is by implementing smart programming strategies. For example, you can combine automatic and manual control signals so that they don't run simultaneously. By using different control states, you can input these combined signals into the PLC efficiently.
Another technique is contact merging. For instance, in a two-start and three-stop relay-contactor control system, instead of using separate input points for each button, you can connect multiple buttons in series or parallel to a single input point. This approach significantly reduces the number of inputs while maintaining full functionality.
Additionally, making full use of the internal functions of the PLC can help optimize resource usage. For example, a single switch can be used as a mode selector (manual/automatic), and branch instructions can differentiate between manual and automatic operations. Using counters or shift registers, you can also implement single-button start/stop functions through alternating output commands.
When it comes to reducing output points, you can take advantage of parallel connections. If the PLC’s output power allows, multiple loads with the same on/off state can share a single output terminal. Similarly, when dealing with BCD displays, you can connect them to four output terminals in parallel, allowing one output point to control multiple devices.
Lastly, some simple control logic may not be involved in the main work cycle or may only need to be activated before the cycle starts. These can be controlled without using the PLC, further saving resources. By applying these methods, engineers can achieve more with less, making their systems more efficient and cost-effective.