Abstract: This paper introduces the technical characteristics of the roll horizontal adjusting device of adjusting machine in hot strip mill of Tisco. The horizontal status of the roll is monitored through special weighing sensor to make sure the total rolls are horizontal level when press rolls touch. Keywords: roll horizontal adjusting, weighing sensor, data communication and measurement instrument I. Overview 1. System Development Background The production scale and product quality of the 2250 production line of Tisco hot strip mill are among the leading in China. Among them , the 17-roll precision straightening machine ( see Figure 1) is a special equipment used for flattening the surface of strip steel and eliminating the internal stress of finished steel plates. To ensure the surface quality of strip steel products, the levelness between the upper and lower rollers requires extremely high precision. We have independently developed and designed a device for adjusting the levelness of the rollers of the precision straightening machine. This device can be applied to the adjustment of the roller levelness of strip straightening systems in the metallurgical industry and is at an advanced level among similar products in China. [align=center] Figure 1 Precision Straightening Machine[/align] 2. Main System Functions Ø Levelness display of straightening roller group Ø Remote communication function Ø Over-limit alarm function 3. System Features Ø Uses dedicated weighing sensors Ø Provides analog or digital interfaces Ø Equipped with a dedicated digital display Ø Provides a digital junction box and dedicated power supply Ø Modular design with high scalability II. Control Principle of Precision Straightening Roller Straightness Detection System 1. Detection Principle and Form Based on the special process and equipment structure of the steel strip cross-cutting unit, ensuring uniform force on the seventeen upper and lower rollers of the precision straightening machine during the straightening of the steel plate is key to improving the yield of high-grade materials. Therefore, selecting the working method of using weighing sensors to detect the force balance of the straightening rollers is reasonable and effective. 2. Selection of Test Points As shown in Figure 2, the straightening equipment consists of 8 upper rollers and 9 lower rollers. There are 4 test points, located at the 4 corners between the upper and lower roller tracks, specifically at the ends of the two rollers between upper roller #1 and lower rollers #1 and #2, and at the ends of the two rollers between upper roller #8 and lower rollers #8 and #9, as shown in Figure 2. [align=center] Figure 2 Schematic diagram of test point locations[/align] 3. Selection of Sensor Type Based on the force conditions at the test points, the two lower rollers are equivalent to the support points on both sides, and the upper roller in the middle is equivalent to the loading point, which is the application mode of a bridge-type weighing force sensor. According to the process requirements, the sensor specification is 10t. The external structure and dimensions of the sensor are shown in Figure 3. [align=center] Figure 3 External Dimensions of the Sensor[/align] 4. Special Technical Specifications of the Sensor 4.1 Utilizing the structural characteristics of the bridge-type sensor, the sensor and the "pressure block" are integrated, making the structure more compact, easier to use, and reducing additional errors caused by installation and other reasons. 4.2 The test results of the weighing force sensor are greatly affected by the sensor's installation position, loading position, and state. To ensure test performance, we adopted a loading head boss structure in the sensor loading head section, which helps improve the sensor's accuracy. 4.3 Since the sensor is used without a weighing platform, its zero point must be positive zero. 4.4 Because the installation level of the roller conveyor is determined by the sensor's output signal, the output sensitivity of the four sensors must be consistent. Currently, our sensor output sensitivity consistency level is 0.1%. 5. Data Acquisition, Processing, and Output 5.1 Digital Transmitter The digital transmitter adopts fully digital processing technology, integrating digital sensors and sensor junction boxes. It performs signal amplification, A/D conversion, digital filtering, and data processing individually on each connected sensor. It can selectively output the A/D internal code and the processed IR code of each sensor as needed; the system can download operating parameters and output data through the host computer command group; the system also has the function of detecting and alarming faulty sensors. 5.2 System Features Ø Employs multiple sensor digital processing technology, significantly improving the output internal code and enhancing data stability when outputting data with the same number of internal codes. Ø Each sensor's calibration coefficient and zero-point coefficient can be individually digitally processed. The potentiometer used for balancing in the original junction box has been eliminated, simplifying the debugging process and improving performance. Ø Utilizes a high-performance microcontroller, a fully sealed stainless steel box structure, and dedicated waterproof metal cable connectors. This enables the system to meet the requirements of moisture-proof, dust-proof, corrosion-proof, electromagnetic field-proof, and electrostatic-proof performance in harsh environments. Ø Employs standard RS-485 asynchronous serial communication, achieving long transmission distances (up to 1200 meters) and allowing direct connection to computers, large screens, and other remote devices. Ø Precise channel calibration ensures consistency of the IR codes output between channels. When the channel's input signal is 0mV, the channel's IR output signal is 0; when the channel's input signal is 15mV, the channel's IR output signal is 30000. 6. System Main Technical Specifications Ø Number of connectable sensors: 1-4; Ø Linearity: 0.02%; Ø A/D conversion speed: 100-200 times/second; Ø Internal decoding capacity: 200,000 codes per channel; Ø Full-scale IR code capacity: 30,000 codes per channel; Ø Input signal range: -1 to +15mV; Ø Digital communication interface: RS-485; Ø Baud rate: 9600 (4800); Ø Excitation power supply: DC5V/120mA; Ø Power supply: DC8V-DC12V; Ø Power consumption: ≤4W; Ø Operating conditions: Ambient temperature: 0℃-40℃; Relative humidity: 40℃ (20-90)%RH; Atmospheric pressure: 86-106kPa. III. Serial Communication Principle and Communication Programming 1. Basic Definition of Serial Communication 1.1 Communication Interface Standard instrument serial interface, which can be selected as the standard serial communication port. The hardware interface is RS-232C or 20mA current loop. 1.2 Communication data format 1.2.1 Baud rate 300, 600, 1200, 2400, 4800 bits. 1.2.2 Data bits and parity method 7-bit even parity. That is, 1 start bit (0), 7 data bits, 1 parity bit (even parity), and 1 stop bit (1). 2. Communication procedure 2.1 Communication control character definition 2.2 Checksum (BCC) algorithm From the characters after STX (02) to ETX (03H) including ETX) data blocks, the XOR result of each data is the checksum (BCC). 2.3 Address encoding The address can be selected from Table 1 to 10 below, and the ASCII code corresponding to the address 3. Data transmission 3.1 Continuous transmission mode. The instrument transmits the lower 5 bits of data displayed on the main display in real time. The transmission format is as follows: Information block BLOCK meaning: WWWWW: ASCII code of the lower 5 bits of the display value, with the most significant bit first and the least significant bit last. e: Exponent of the weight value: for example, a weight value of 500.0 kg is represented as 0.05000 × 10⁴ in floating-point form, so e = 4. m: Dynamic detection bit. m = 1 when weighing is in a dynamic state; m = 0 when weighing is in a stable state. 3.2 Discontinuous transmission mode (i.e., command response mode) 3.2.1 Command transmission and reception communication description The communication steps are shown in the figure below. During the entire communication process, the host computer performs three stages of question-and-answer communication: link response, command transmission, and data reception. 3.2.2 Link response: At the start of communication, the host computer first sends SOH, ADDR, POL, and ENQ to call a slave device at a certain address. The slave device at that address then sends back the response signal EOT. 3.2.3 Command Sending: After receiving the EOT response, the host computer begins sending commands to the slave device: SOH, ADDR, STX, BLOCK, ETX, BCC, ENQ. The slave device responds with NAK, indicating that the slave device's data reception is incorrect. The host computer retransmits the command. If the host computer receives NAK responses after three consecutive command transmissions, it indicates a communication failure and the communication ends. If the slave device responds with ACK, it indicates that the slave device's command reception is correct. 3.2.4 Data Reception: After receiving the ACK response, the host computer sends SOH, ADDR, POL, ENQ, and then receives the data returned by the slave device. The slave device responds with SOH, ADDR, STX, BLOCK, ETX, BCC. If the host computer correctly receives the data returned by the slave device, it sends ACK and ends the communication. If the host computer receives incorrect data, it responds with NAK, and the slave device retransmits the data. If it receives NAK responses after three consecutive transmissions, it indicates a communication failure and the communication ends. Parameter Explanation: e — The exponent of the weight value (0. WWWWW × 10e) m = 2 Weighing is in a stable state. 4. Example: The following instructions all set the XK3115 address to 1, i.e., ASCII code A (41H), and send data in ASCII code. Numbers are represented in hexadecimal. The display shows 100.0 kg, and the weighing is in a stable state: SOH ADDR STX WWWWW em ETX BCC ENQ 01 41 02 30 31 30 30 30 34 30 03 36 0A IV. Beneficial Effects and Promotional Applications Before the successful development of the straightening roll flatness detection system, the leveling method for Taiyuan Iron & Steel's straightening rolls mostly relied on direct length measurement. This involved using a reference surface and measuring whether the distance from the roller contact surface to that reference surface was equal, thus determining whether the roller conveyor was level overall. However, this leveling adjustment had high requirements for the reference surface and only ensured levelness visually; it could not guarantee the overall levelness of the roller conveyor after the pressure rollers deformed. For metals of the same material, deformation and the resulting force have a certain functional relationship. Therefore, the problem of measuring distance in horizontal adjustment can be transformed into force measurement. That is, by detecting the force generated after the pressure roller deforms, the magnitude of the deformation is indirectly reflected, thereby indicating the state of the roller conveyor's horizontal adjustment. The flatness detection system has been successfully applied to the cross-cutting and straightening process of strip steel of plain carbon steel and various stainless steel grades. It can improve work efficiency and operational accuracy, significantly increase the yield, and generate significant economic benefits. This system is currently applying for a national patent.