There might be something wrong with the sensor in the number 2 production line.
第2条生产线的传感器好像状态不佳。
Could you describe the problem in more detail?
能具体描述一下问题吗?
The sensor can detect white caps but not black ones.
白色瓶盖能检测到,但是黑色瓶盖检测不到。
Well, did you set up the sensor adjusted to the reflection rate of the white cap? If so, I think that's the reason why the sensor is not responding. The reflection rate of a black object is lower than a white one. So if you set the sensor to the same reflection rate of the black cap, the sensor will be able to detect both black and white caps!