Many of the sensor and robot control lines in smart factories are still 485 buses. They pass through the dense area of ​​frequency conversion cabinets and welding machines, and bit errors occur from time to time. The method of review is to first confirm whether the copper cable section can be saved before deciding to polish it, rather than directly replacing the equipment.

The phenomenon of code errors is identifiable

Errors due to insufficient power supply are often caused by random packet loss; frequency conversion interference appears in a regular pattern - it occurs along with the speed adjustment action, manifesting as repetition of the entire frame, verification failure, or occasional offline offline of the slave station. Statistics of the error logs of the acquisition software are made on an hourly basis. If the peak value coincides with the device start-stop curve, the benefits of media modification are usually greater than parameter adjustment.

First make three sections of measurements on the copper cable

• Voltage at the beginning and end of the bus: determine whether the terminal resistor is added and whether the impedance matches;
• The potential difference between the shielding layer and the signal ground: determine whether a ground loop is formed;
• Segment removal: Disconnect from the middle junction box to see if the error only occurs in a certain segment.

There is still no improvement after three sections of testing, indicating that the line passes through a continuously strong field area, and continuing to adjust the baud rate will only eat up the margin even thinner. Use at this time2-way bidirectional RS485 data optical terminalThe section that passes through the interference zone is replaced with optical fiber, and both ends are still connected to the original bus equipment. The amount of on-site changes is controllable. The light of the wolf isSmart factory industrial network transformation for an auto parts manufacturerThe robots are grouped and carried in the middle, and then collected in the centralized serial port management position on the workshop side.

There are still two things to do after glazing

First, the baud rate and check bits are consistent at both ends. Transparent transmission does not mean that parameters cannot be checked; second, the segmented wiring diagram of the original bus is retained to clarify which slave stations are hung on which optical channels, so that subsequent new devices will not have address conflicts. Transformation scope comparisonIndustrial automation and machine vision network solutionsChapter 485 confirmed.

Distance, power supply and interference sources are all compared on the plan page. If you are unsure, send the on-site measurement values ​​to technical support for judgment together.