Abstract : The TPS control system is an automated system that unifies the entire factory's information system and production process control system on a single platform. It features strong control functions, ease of operation, and high reliability. This paper discusses the characteristics, redundant network structure, and control functions of the HONEYWELL TPS control system, and, based on the company's actual situation, illustrates the application of the HONEYWELL TPS system in a circulating fluidized bed boiler. Keywords : TPS system; Circulating Flow Bed Boiler; Redundancy; Control 1 Introduction With the continuous increase in market demand and the continuous expansion of the company's projects, the company decided to add a 260T/H CFB boiler to the existing two 130T/H circulating fluidized bed boilers (CFB boilers). Although CFB boilers have advantages such as high combustion efficiency, wide coal adaptability, low NO emission concentration, and large load adjustment range, their structural complexity far exceeds that of ordinary boilers, which places higher demands on the normal operation of the boiler. The Honeywell TPS control system adopts multiple redundancy settings, which increases the reliability of the system. Its powerful logic control function is the guarantee for the long-term safe and stable operation of the system. 2 System configuration and features The TPS system is an integrated solution control system launched by Honeywell Corporation of the United States based on the TDC-3000 system. It unifies the factory's information system and production process control system on one platform. It introduces the latest computer system software and hardware technology platform, integrating the Windows 2000 operating system, OLE public software, and ODBC public database technology to form a powerful, flexible, and open automatic control system [1]. 2.1 System Configuration The entire TPS system is configured with two pairs of redundant High-Performance Process Managers (HPMs), node numbers 11 and 12 and 13 and 14 respectively. Their main functions are rapid internal data processing and powerful storage capabilities, as well as control capabilities for sharing data through point-to-point communication via the UCN network, ultimately completing the scanning and control of TPS system process data. A pair of redundant Network Interface Modules (NIMs), node numbers 21 and 22, are mainly used for system configuration, communication, alarms, command processing, clock broadcasting, etc. A common History Module (HM), node number 25, is used to store the entire system's system files, attribute files, user configuration files, process parameters, and their generated historical data. Three GUSs (Operator Stations) are used for operators to monitor and control the entire production process, and one engineering station is used for configuration and debugging. GUSs and engineering stations are redundant, and all GUSs and engineering stations have the same configuration, serving as backups for each other, greatly improving system safety and reliability. The entire system is connected through a redundant UCN network and a redundant LCN network. The specific configuration is shown in Figure 1. [align=center] Figure 1 System Configuration Structure Diagram[/align] 2.2 System Features The TPS control system adopts redundant settings in many places, which increases the reliability of the system. In addition, the digital input signals from electrical equipment and all digital outputs are isolated by relays and are not directly connected to the system to avoid instantaneous large current and high voltage entering the system and causing damage to the system equipment. In addition, the I/O cards, communication cards and networks of the system also have self-diagnostic functions. Any fault can be clearly displayed on the operation interface and the fault can be eliminated as soon as possible [2]. 3 System Control Functions 3.1 Process Point Functions In the TPS control system, the process point is the smallest unit that makes up the control loop. The connection relationship between points is completed by defining the input and output connection parameters of the points. The process points are divided into points in I/O and points in HPM. (1) Points in I/O include: Analog Input Point (AI): Converts the received field analog input signal into PV value expressed in engineering units. Analog Output Point (AO): Converts the OP value into a 4~20mA signal and outputs it to the actuator. Digital input point (DI): By selecting different FTAs, it can process 24VDC, 110VAC or 220VAC digital input signals. Digital output point (DO): Accepts the output of the control algorithm and converts it into 24VDC, 110VAC or 220VAC digital signals through FTA. (2) The points in HPM include: Regular processing point (RPV): Provides further processing of process variables. By selecting the relevant PV processing algorithm, it can complete 9 control algorithms such as input variable selection, flow compensation calculation, flow accumulation, and piecewise linear function. Each PV point must define at least one input connection and cannot define an output connection. Regular control point (RC): Provides various algorithms related to standard control schemes. It has a large number of built-in control functions. Using these algorithms greatly simplifies the implementation of complex multi-loop control schemes, such as PID, PID with feedforward, ratio controller, function controller and 13 other control algorithms. Digital combination point (DC): Provides a control operation panel for discrete equipment such as motors, pumps, solenoid valves, etc. It is a multi-input multi-output point with interlocking function. Logic point: includes three parts: input conditions, logic operation blocks, and output conditions. The logic execution process is illustrated. One logic point is equivalent to two pages of ladder diagram function. 3.2 Implementation of control scheme The control system of our company's 260T/H CFB boiler mainly includes four parts: data acquisition system (DAS), sequential control system (SCS), analog control system (MCS), and boiler furnace safety monitoring system (FSSS). Its successful application has realized the functions of real-time data acquisition, process control, sequential control, alarm control, monitoring, operation and data remote transmission in industrial production process, which has improved the overall automation level, optimized the working conditions and ensured the stable production of the system. (1) DAS function: realizes the data acquisition function required for process personnel monitoring. (2) MCS function: corrects some parameters of analog quantity to ensure the balance and stability of the system. It mainly includes boiler drum water level control, main steam temperature control, main steam load control, furnace bed temperature control, furnace pressure control, coal control, air volume control, etc. A total of 40 sets of analog quantity automatic adjustment systems were designed. The logic control of the MCS system in a CFB boiler is introduced using boiler drum water level control as an example, as shown in Figure 2. The boiler drum water level is controlled by adjusting the opening of the main and auxiliary feedwater regulating valves on its feedwater pipeline. When the boiler load is between 0% and 30%, it is controlled by the auxiliary feedwater regulating valve; when the boiler load is greater than 30%, it is controlled by the main regulating valve. During normal operation, the control is controlled by a three-impulse control system consisting of steam flow, drum water level, and feedwater flow. During startup, only the single-impulse control of the drum water level is used. The switching between single-impulse control and three-impulse control is disturbance-free. In abnormal situations, the control system switches from automatic to manual operation [3]. [align=center] Figure 2 Drum water level logic control diagram[/align] In the logic diagram, C1 is the compensation coefficient for feedwater flow and steam flow. The main and auxiliary feedwater regulating valves have two control modes: manual and automatic. During boiler start-up or shutdown, due to the unstable system conditions, the regulating valves are switched to manual control. During normal system operation, since the entire system is relatively stable, the main and auxiliary feedwater electric valves can be put into automatic control mode. The regulating valve will automatically adjust the valve opening according to the setting value of the steam drum liquid level set by the process personnel. When the liquid level decreases, the valve opening increases; when the liquid level rises, the valve opening decreases. This control mode not only enables the system to operate safely and stably, but also facilitates the operation of the process personnel. (3) The SCS function is to control the operation, interlock protection, status monitoring and abnormal alarm of the pumps, machines, electric valves and remote control equipment related to the boiler. It mainly includes feedwater pump start-stop logic, primary air fan start-stop logic, secondary air fan start-stop logic, return air fan start-stop logic, induced draft fan start-stop logic, and coal feeder start-stop logic, etc. A total of 38 sequential control logics are designed. Here, the control and protection of the induced draft fan is used as an example, as shown in Figure 3. Let's experience the powerful SCS control function of the TPS system. [align=center] Figure 3 Start-up and shutdown logic diagram of the induced draft fan[/align] In the logic design process, in order to control the induced draft fan safely and reliably and reflect the actual control process of the induced draft fan, the front and rear bearing temperatures and vibrations of the induced draft fan, the opening degree of the inlet baffle, and the operating status feedback signals were introduced. NN1～NN5 are internal value registers provided by the logic point, which are used to store the internal constants of the baffle opening, bearing temperature and vibration respectively; FL12 is an internal flag register provided by the logic point, which is mainly used to engage and disengage the induced draft fan interlock. When the induced draft fan interlock is engaged, FL12 is "TRUE" and when the induced draft fan interlock is disengaged, FL12 is "FALSE"; P1 is the allowed interlock parameter. When the opening of the induced draft fan inlet baffle is less than NN1, the induced draft fan is allowed to start; I0 ​​is the forced interlock parameter. When the vibration of the front and rear bearings of the induced draft fan is greater than NN2, NN3 or the temperature of the front and rear bearings is greater than NN4, NN5, the induced draft fan is forced to stop; CMDDISFL means that the command is not executed and UNCMDFL means that the command is executed. When these two faults occur, the induced draft fan will be forced to stop. (4) FSSS function: ensure the normal start-up and safe operation of the boiler system. It mainly includes the boiler main interlock, ignition control, etc. The following example uses the Emergency Shutdown Total Interlock (MFT) logic, as shown in Figure 4. This section introduces the control functions of the FSSS system in the CFB boiler's total interlock. [align=center] Figure 4 CFB Boiler MFT Logic[/align] To ensure the safe and stable operation of the CFB boiler, the furnace pressure, drum water level, drum pressure, and high header outlet pressure in the MFT interlock all use a 3-to-2 logic. If two of the three high-high furnace pressure signals reach the high alarm value, the MFT interlock will be triggered. The induced draft fan, primary air fan, and secondary air fan use AND gate logic; if any one of the six fans stops operating, the MFT interlock will also be triggered. If an emergency shutdown is required for reasons other than those mentioned above, the emergency shutdown button on the control panel can be pressed directly to trigger the MFT interlock, ensuring the safe operation of the system. 4 Conclusion Honeywell TPS, as a mature distributed control system product, has strong practicality in actual production. The powerful functional modules of the control system software and the superior performance of its hardware ensure that the boiler system is put into operation within the predetermined time according to the design scheme and without faults. Its control accuracy fully meets the production requirements. The commissioning rate of the regulation control system reaches 96%, which brings convenience to operators and system maintenance personnel and plays a positive role in promoting the company to further realize integrated management and control. References [1] Honeywell TPS Training Manual, published by Honeywell Automation Design Institute [2] Industrial Control Computer, Chemical Industry Press [3] Guotai Chemical Power Plant Boiler Engineer Manual Author Introduction Lei Ningbo, male, born in December 1980, currently works at Yankuang Guotai Chemical Co., Ltd., assistant engineer, graduated from Shenyang Chemical Institute, and is currently engaged in DCS system development and configuration maintenance.