1. Sensor failure: If the position sensor is used, the sensor may fail, resulting in the PLC not reading the position information correctly. It is necessary to check whether the sensor works normally and whether it needs to be replaced.

2. Signal interference. If the position signal received by PLC is disturbed, the reading may be inaccurate. Need to check whether the signal line is connected correctly and whether there is interference source.

3. Power supply problem: If the power supply of the PLC is unstable, it may cause the PLC to be unable to read the position information correctly. Need to check whether the power supply is normal and whether it needs to be replaced.

4. Program problem: If there is an error in the PLC program, the read value may be inaccurate. Need to check whether the program is correct and whether it needs to be modified.

5. Mechanical problems: If the mechanical parts fail, the position may be inaccurate, resulting in inaccurate values read by PLC. Floating-point arithmetic instructions (FNC110-FNC1320) are used to handle floating-point numbers. Floating point number is 32 bits, including 13 instructions such as comparison, transformation, four operations, square operation and trigonometric function.