The traditional control methods used in old heat exchange stations often have problems such as low efficiency and strong dependence on manual work, which makes it difficult to meet the stability and precise control requirements of modern heating. With the advancement of the digital transformation of the heating industry, more and more companies are beginning to consider upgrading old heat exchange stations to PLC (programmable logic controller) automatic control systems to achieve stable and controllable heat transfer and accurate collection of operating data. Below, Henan Rentai will discuss how to smoothly complete the upgrade and transformation of old heat exchange stations to PLC control systems while minimizing or stopping heating.
The necessity and advantages of upgrading PLC control systems
**Improve control accuracy and efficiency:**The aging and maintenance difficulties of traditional heat exchange station equipment lead to poor heating effects and low energy utilization efficiency. After the introduction of PLC control, the heating system can be accurately controlled and flexibly adjusted through high-precision algorithms, which can improve control accuracy while effectively reducing energy consumption. The rapid response capability of PLC can also automatically adjust the operation of water supply pumps, regulating valves, and circulation pumps according to load changes such as outdoor temperature, and adapt to heating needs more quickly and accurately. For example, after adopting PLC in a certain upgrade project, the heating control accuracy was significantly improved and energy consumption was significantly reduced.
**Achieve automation and safe operation: **The PLC system has the ability to run according to the program for 24 hours continuously, which is suitable for unattended automation control needs. The control cabinet based on PLC has a fast processing speed and can execute complex logic, realize local automatic control, remote centralized control and other methods, and effectively improve the convenience of operation. At the same time, the PLC system can continuously monitor the water temperature, water pressure, water flow and other parameters of the pipeline network, and automatically adjust according to the program settings, timely alarm abnormal conditions, and enhance the safety of equipment operation. Through algorithm optimization, PLC can also finely control the heating curve to maximize energy conservation while ensuring comfortable room temperature.
**Support remote monitoring and data acquisition: **Compared with traditional analog control or relay control, PLC is easy to integrate with communication modules to realize data networking between the heat exchange station and the dispatching center. After installing a communication network module (such as Ethernet or wireless module), the dispatching center can remotely monitor and dispatch the unattended heat exchange station. This lays the foundation for centralized management and big data analysis of the heating system and creates conditions for further SCADA systems. In the context of digital informationization, PLC collects and uploads equipment data in real time, providing reliable data support for heating operation optimization and maintenance.
Key steps for smooth upgrade implementation
**1. Preliminary evaluation and solution design: **Before the transformation begins, the control cabinets, sensors, actuators, etc. of the existing heat exchange station should be comprehensively surveyed and evaluated. Analyze the control logic and equipment interface of the original system to determine which equipment needs to be replaced and which can be retained. The approximate service life of the original products needs to be predicted. According to the evaluation results, professional engineers will formulate an upgrade plan, including the selection of appropriate PLC models, I/O module configuration, human-machine interface (HMI) size and control strategy, and the estimated service life of the original retained products. Professional companies such as Henan Rentai Electrical Equipment Co., Ltd. usually provide pre-sales consulting services such as demand analysis, technical exchanges and solution design to ensure that the solution meets functional requirements and is economically feasible.
**2. Hardware installation and phased transformation: **In order to minimize downtime, the upgrade and transformation should be arranged during the non-heating period or low-load period, preferably the non-heating period. First, install the new PLC control cabinet and related supporting equipment, such as sensors, frequency converters, etc., on site, but try to keep the original pipeline equipment in normal operation. If possible, the new and old systems can be run in parallel for a period of time: that is, install and debug the main part of the PLC system first, but do not switch the control temporarily, let the PLC read the data in monitoring mode, and compare it with the output of the original system. This parallel debugging can verify the function of the new system without interfering with the heating. For components that need to be replaced (such as old electrical components, relays, contactors, etc.), they should be prepared in advance and replaced at one time. During the construction process, be sure to comply with safety regulations: power off the operation, do a good job of protection, protect the original equipment interface, and avoid impact on the pipeline network and equipment.
**3. Software programming and debugging test: ** According to the requirements of the heating process, compile the control program in the PLC, including the temperature control algorithm on the primary and secondary sides of the heat exchanger, the start and stop of the circulation pump and the make-up water pump and the frequency conversion adjustment logic, the valve opening adjustment, etc. The debugging stage can be divided into unit testing and overall joint debugging: first test the sensor signal acquisition and actuator control to see if they are normal, and then test the entire heat exchange station control system under no-load or low-load conditions. Focus on verifying the outlet water temperature control accuracy, pressure stability, and whether the alarm interlocking functions meet the design requirements. For example, set up simulated over-temperature and over-pressure conditions to check whether the PLC can alarm and interlock the shutdown in time to ensure that the safety function is effective. Henan Rentai's engineers will carefully check each parameter during on-site debugging to ensure that the new control system meets the predetermined performance standards. In this process, the switch between the old and new systems should be cautious and gradual to ensure that once a problem occurs with the new PLC, it can quickly switch back to the original control mode to avoid heating interruption.
**4. System switching and verification optimization: **When all functions of the PLC control system have been repeatedly tested and confirmed to be correct, the heat exchange station can be switched from the original control mode to the PLC automatic control mode. In the initial operation stage, a dedicated person is arranged to monitor and verify the stability of the system under different working conditions. For example, the control effect of temperature and pressure under low load at night and peak during the day, and optimize the control parameters and logic algorithms according to the actual situation (such as optimizing the control algorithm of the heating curve to cope with weather changes). Ensure that under various working conditions, the outlet and return water temperatures of the heat exchange station can be stabilized within the set range, and the indoor heating meets the comfort requirements. At the same time, pay attention to whether there are abnormalities in the interface between the PLC and the original equipment, such as checking whether the old valves and pumps retained under the control of the PLC are reliable, and whether there are signal errors. If necessary, use an interface adapter or add a signal conditioning module to solve the problem of device interface mismatch to ensure smooth docking of new and old equipment. After a period of stable operation and optimization, the upgrade work is basically completed.
**5. Training and follow-up guarantee: **After the upgrade is completed, training for the operation and maintenance personnel of the heating station is an indispensable part. The training content includes the basic operation methods of the PLC control system, the explanation of the HMI interface functions, and the processing procedures of common alarms and faults. Through training, the on-duty personnel understand the principles and system interfaces of automatic control, learn to switch to manual mode when necessary, and ensure safety in emergencies. Henan Rentai Electric usually provides on-site training services when delivering projects, covering all aspects from basic operations to advanced fault diagnosis, and enhancing the ability of operators to handle problems independently. In addition, establishing a sound after-sales support mechanism is also a guarantee for smooth operation. For example, Rentai Electric provides 7×24 hours remote technical support and regular inspection services, which can remotely monitor the operating status of the control cabinet through the Internet of Things platform, perform fault diagnosis and emergency maintenance response. These measures ensure that the heat exchange station can continue to operate stably even in the operation stage after the upgrade.
**6. Step-by-step transition and experience feedback: ** Throughout the upgrade process, the data and experience collected during the trial operation and transition period should be fully utilized to continuously improve the system. For example, analyze the historical operation data recorded by the PLC, find out the space for energy efficiency improvement in the heating system, and further optimize the control strategy. Problems found in the upgrade (such as leakage of some old pipeline valves, inaccurate individual sensors, etc.) should be dealt with in a timely manner to accumulate experience for the next similar renovation project. In practice, it is very important to choose a professional team with rich experience to implement the upgrade. Experienced engineers can foresee the difficulties and risks in the renovation, formulate emergency plans, and make the upgrade process smoother.
Conclusion
Upgrading old heat exchange stations to PLC control systems is the only way to achieve intelligent and efficient heating systems. Through careful preliminary planning, professional construction and commissioning, and perfect training and operation and maintenance, the impact of the upgrade on heating can be minimized and a smooth transition can be achieved. The successfully upgraded heat exchange station will significantly improve temperature control accuracy, energy conservation, and operational reliability, bringing a win-win effect to heating companies and users. Henan Rentai Electric Equipment Co., Ltd. has rich experience and technical advantages in the automation transformation of heat exchange stations. It can provide customized solutions integrating PLC+HMI and full professional services to ensure the safety and efficiency of the upgrade and transformation process, and give new vitality to old heat exchange stations. For more information, please contact Henan Rentai Electric immediately: Tel: 86-17638563962 / 0371-56520104 and Email: info@hnrentai.com.