Recent developments in the cement industry have led to widespread adoption of advanced computational technologies for automating production processes. Many newly built or upgraded medium- and large-scale cement production lines now rely on Distributed Control Systems (DCS). Unfortunately, numerous smaller plants still lag behind technologically, depending heavily on traditional instrumentation or even fully manual operation. These outdated practices negatively impact product quality and output, while preventing plants from improving energy efficiency, lowering operational costs, and remaining competitive. Because large-scale DCS platforms require significant upfront investment, many small facilities simply cannot afford them. To address these challenges, a lower-cost, highly reliable DCS solution was developed and deployed.
The operating environment in a cement plant is extremely harsh, characterized by high temperatures, heavy dust, wide-ranging electromagnetic interference (EMI), and measurement points distributed across large distances, resulting in high wiring costs. After evaluating various manufacturers to identify the best price-to-performance options, the I-7000 Series remote data acquisition modules, industrial computers, and related I/O devices from ICP DAS USA were selected.
The complete system is divided into five functional subsystems based on the cement production workflow:
Raw mill supervisory system
Vertical mill calcining process supervisory system
Cement mill supervisory system
Rotary kiln supervisory system
Distribution equipment operation and power-consumption supervisory system
Both the raw mill and cement mill subsystems can automatically start and stop. They continuously monitor and adjust the temperature and oil-supply current of key equipment, optimizing performance through parameter-based regulation.
The vertical kiln subsystem includes automated equipment status monitoring, raw-mill ball formation control, fire-offset correction, and intelligent calcining process management.
The rotary kiln subsystem integrates control of the wet mill and coal mill, enabling partially automated, synchronized monitoring of equipment performance, production, and energy consumption along the kiln line.
The distribution subsystem monitors transformer operation and major equipment in all distribution rooms and automatically generates detailed logs.
Each subsystem connects to the company’s existing management network via Ethernet, uploading organized and time-stamped data for supervisors and plant management.
The vertical kiln subsystem consists of three hierarchical levels—workshop management, workshop control room, and workshop field level (Figure 2). Communication among these levels is achieved through RS-485 networking. Technical parameters of the vertical kiln are collected by I-7018, I-7033, I-7050, I-7021, I-7041, and similar modules.
Ball-formation automation utilizes the I-7188 embedded controller, TOUCH-200 HMI, and several I/O modules (I-7016, I-7080, I-7021), along with strain gauges, flow sensors, and various transducers.
To maintain stable moisture content in the chamotte, the system uses an I-7188 controller, an I-7016 analog input module, strain gauges, and SRR sensors to automatically measure and regulate water content. This ensures the kiln output remains stable, even when kiln-outgoing chamotte levels fluctuate.
In the central control room, the I-7188 (configured with multiple serial ports) serves as a data buffer between field devices and the IPC, allowing two to three IPC stations to run concurrently and independently adjust system parameters.
The workshop control room IPC is responsible for real-time computing, display, analysis, storage, and control. Operators can issue adjustment commands, which are delivered to field output modules via IPC to drive actuators and control mechanisms.
At the management level, the IPC handles advanced data analysis, long-term storage, and the generation of standardized control values for each technical parameter based on operational benchmarks.
Due to the complexity of the system, requiring user-friendly HMIs, real-time monitoring, and reliable process control, IPC control software in Visual Basic 5.0 for Windows was developed. The application includes system management, process-flow visual simulation, instrument-panel simulation, database management, data communication, and control algorithm modules. Extensive use of ActiveX controls reduced development time significantly.
For the I-7188 controllers, the plant used library files provided by ICP DAS and programmed in QuickBasic. Approximately 200 KB of memory is sufficient to run core control functions, including data processing, communication, and an interactive human-machine interface for raw-material ball-formation control.
The system was first installed on a production line in early 1998. After performance improvements, it was successfully expanded to five production lines by 1999. The DCS solution stabilizes vertical kiln thermal conditions, increases output, and improves chamotte quality by maintaining optimal ball-formation ratios and balancing material inflow and outflow.
Throughout operation, system reliability has remained exceptionally high, with virtually no failures. Additionally, we replaced traditional hard disks with ICP’s IDE Flash Disks to eliminate read/write errors in harsh environments.
Because I-7000 Series modules communicate via RS-485, they support long-distance networking over simple twisted-pair wiring. The system benefits from fast communication speeds, high-resolution sampling, intelligent processing, optical isolation, robust EMI protection, and dual watchdog timers. These features increase system reliability, enhance data acquisition speed, and simplify software development. The host computer connects using an RS-232 interface, allowing nearly any computer with an RS-232 port to join the network, improving interoperability and minimizing maintenance challenges.
With the I-7000 series’ self-adaptive communication features and the I-7188’s multiple serial ports, even legacy equipment (such as older transducers and intelligent instruments) can be integrated into the network, protecting prior investments.
After completing the vertical kiln project, we continued expanding the same architecture across other subsystems because the I-7000-based solution consistently met production requirements while offering excellent performance at a competitive cost. Overall, the implementation of this system represents a significant advancement in automation, efficiency, and operational management across our cement production facility.
