# Research on Data Transmission of Laser Sensors for Reading Ruler
## 4 Sensor Technology and Code Reading Error Analysis
### Detection of Yardstick Swing
reliable and is not disturbed by ambient temperature fluctuation. It supports RS-485 and SSI interfaces, which can directly and efficiently transmit the location data to the controller to enable seamless information docking. The reader of the WCS position coding system is firmly installed on the conveyor body, and the coding ruler is installed on the guide rail pad in parallel so as to ensure real-time and accurate code reading and positioning during operation [10; 21; 22]. Inside the U-shaped reading wharf, a laser transmitter is installed on one side, and a laser receiver is installed on the other side. The beam emitted by the transmitter is received by the corresponding receiver and converted into a digital signal. When the code reader is installed on the ruler track, the lightproof encoder blocks the beam emitted from one side, and the receiver cannot receive the optical signal, so the digital signal \"0\" is output. With the relative displacement of the code reader on the coding ruler track, the correlative laser sensor passes through the coding grid carved on the coding ruler, and the beam normally receives and outputs the digital signal \"1\". There are 24 laser sensors installed in close arrangement inside the reading wharf. A 24-bit 0/1 code can be obtained by recording 24 0/1 digital signals. With the movement of the code reader on the yardstick, the read code changes accordingly. Then, the corresponding decoding algorithm obtains the specific displacement of the current position relative to the zero point according to the coding principle. One end of the yardstick track is fixed, and deviations of two or more degrees of freedom indicate shaking. As shown in Figure 6, only three ranging sensors are installed at the corresponding positions on both sides of the reader and at the same horizontal position on the same side in order to effectively detect whether the yardstick swings. This design not only improves the detection accuracy but also enhances the stability and reliability of the system. Once the installation is completed and successfully commissioned, these ranging sensors begin to function. The sensor can quickly sense yardstick swing and output the corresponding signal. We can accurately analyze the swing of the decoding ruler by collecting and processing these signals so as to take corresponding measures for adjustment and correction. Figure 5: Code reader structure. Figure 6: Sensor layout. The laser sensor detects the oscillation of the code ruler, with a dynamic minimum detection threshold of \(\pm 3\) mm, and the reader moves along the code ruler at a speed of 1.5 m per second. The impact vibration from the consolidation machine is significant and the operating environment is harsh. The minimum amplitude sensitivity detected by the system is less than or equal to 20%. In addition, multi-point monitoring of the yardstick can be achieved by installing multiple ranging sensors. This can not only improve the accuracy and reliability of the detection but also help us to more comprehensively analyze the swing of the decoding ruler. It can be determined whether the yardstick swings evenly and whether there are abnormal points by comparing the sensor data at different positions.