APPC 1533T-P20s Exercise Strict Control & Monitoring over Steelmaking Quality

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NexAIoT’s panel PC-based softlogic controllers have replaced programmable logic controllers (PLCs) in a heat treatment furnace, seizing control of steelmaking processes and showing a firm grasp of processing status. By modernizing the heat treatment furnace with NexAIoTM’s panel PC-based softlogic controllers APPC 1533T-P20s, NexAIoT’s steelmaking client is able to control and monitor the furnace operations in real time, shifting from passively responding to production issues to proactively engaging in heat treatment processes.


Heat treatment is a series of heating and cooling processes which provide strength, toughness, and ductility along with other physical properties for steel and require precise control and real-time monitoring. However, the client’s heat treatment furnace was a PLC-based control system which allowed batch process control yet kept processing information only onsite. If a temperature inside the furnace had exceeded a safety range, an operator would have received an alert and reported to process engineers and then to plant managers. The practice was out of date and caused a few hours’ delay in taking corrective actions. Therefore, the client needed an advanced solution to bring everyone on the same page at the same time.

The client attempted to add the remote monitoring function to its PLC-based control system but was deterred by vendor lock-in and costly system migration. On the quest for an economically feasible solution, the client has found NexAIoT’s APPC panel PC-based softlogic controllers and revamped the system with 15-inch APPC 1533T-P20s through the help of Onx Control Systems.


In a steel mill the APPC 1533T-P20 has taken control of a heat treatment furnace over PLCs. Connecting to existing remote I/Os over PROFINET communication, the APPC 1533T-P20 monitors the temperature, regulates it to a specific level by adjusting the amount of air inflow and outflow, and incorporates burner igniters to accelerate and decelerate temperature changes. Also the panel PC-based softlogic controller keeps gauging the furnace atmosphere and alters the mixture of gases accordingly with gas vales.

During the heat treatment processes, information including temperature, gas concentration, and valve status is displayed in real time on the 15-inch display of the APPC 1533T-P20 onsite as well as the APPC 1533T-P20 in a plant manager’s office.

Solution Benefit

With NexAIoT’s APPC 1533T-P20s, real-time information generated from the steel mill is sent to the office from which a plant manager can oversee temperature profiles and alarm events, identify and rectify abnormal temperature fluctuations that could affect the microstructure and quality of steel, and track and analyze data trends for possible process optimization.

Moreover, the modernized system has a streamlined architecture supporting function consolidation and cross-vendor interoperability. In this project the onsite APPC 1533T-P20 running CODESYS Control RTE and CODESYS TargetVisu software combines controller and HMI functions that relied on separate hardware and works harmoniously with original SIEMENS remote I/Os so it can control and monitor meters, values, and other instruments. Meanwhile, the APPC 1533T-P20 in the office runs CODESYS Remote TargetVisu to provide a live view of furnace status.