TECHNICAL SUPPORT
Published 2026-03-21
When you get the serialservo, the first thing you need to do is check the power supply. This type ofservousually requires a separate power cord. The red wire is the VCC positive pole and the black or brown wire is the GND negative pole. You must not connect it directly to the 5V pin of the control board. Especially when multipleservos are used together, the current will be large and the board will be burned in minutes.
The correct approach is to use an independent power module, such as a battery or regulated power supply with a voltage range between 6V and 7.4V. This power module can provide stable and reliable power support for subsequent operations.
The wiring process is relatively simple: connect the positive pole of the power supply to the red wire of the servo, and the negative pole to the black wire. At the same time, connect the negative pole of the power supply to the GND of the control board. This operation is called common ground. If there is no common ground operation, the signal will drift chaotically, and the servo may either remain stationary or experience abnormal shaking and other draft phenomena.
The serial port servo uses UART communication method, which involves two signal lines, TX and RX. If you carefully observe the signal wires on the servo, you will find that usually the yellow or white wire represents TX, while the green or blue wire represents RX. ️ When performing wiring operations, you need to use a cross connection: connect the TX of the control board to the RX of the servo, and at the same time connect the RX of the control board to the TX of the servo. This is like two people talking on the phone, one party is responsible for listening and the other party is responsible for telling, and they exchange information between each other.
Don’t underestimate this step. Many novices use direct connection to cause communication failure. If you are using a servo with an RS485 interface, you need to connect wires A and B. This is suitable for long distance or multiple servos in series. No matter which one, confirm the agreement before wiring, don't guess based on your feelings.
Do you think that as long as the wires are connected correctly, the order does not matter? Not really. There is a golden rule in the wiring sequence: connect the ground first, then the power supply, and finally the signal wire. This is done to prevent surge current from burning the control board or servo during the wiring moment.
For example, if you connect the power cable first and then the signal cable, the power supply may be momentarily short-circuited due to jitter during the process. ️ The correct sequence is: first connect all GND wires, then connect the power wires, and finally plug in the signal wires. Developing this habit can help you save a lot of time and money on repairs.
When you use multiple serial port servos in a project, wiring is not as simple as one-to-one. In the power supply section, parallel operation is required. Specifically, the red wires of all servos must be brought together and then connected to the positive terminal of the power supply. At the same time, all black wires must be brought together and connected to the negative terminal of the power supply. ️ What needs special attention here is that the power of the power supply must be sufficient. Because when one servo is blocked, it may generate several amps of current. If three servos are running at the same time, it will be impossible to drive them without a power supply of tens of watts.
As for the communication part, if UART is used, usually a control board only has one serial port, so the "bus" mode needs to be used. Many serial port servos support ID numbers. The TX and RX of all servos can be connected in parallel to the corresponding pins on the control board, and then a single servo can be controlled by sending instructions with different IDs. This is just like a roll call. When the ID of the servo is called, the servo will take action.
In actual operation, this method brings convenience to the steering gear control. By properly setting the ID number, each servo can be accurately controlled to achieve diverse action combinations. Whether it is a simple angle adjustment or a complex coordinated action, it can be easily achieved with the help of this communication mode. Moreover, this parallel connection method also simplifies the wiring process, reduces the occupation of hardware resources, and improves the stability and reliability of the system.
After the wiring is completed, don’t rush to install it on the machine. Power-on test is necessary. The first thing is to use a multimeter to measure whether there is a short circuit between the positive and negative poles of the power supply, and then turn on the power after confirming that it is correct. ️ After powering on, touch the servo and control board to see if there is any abnormal heat. If so, cut off the power immediately. Nine times out of ten, it is a wiring error.
Then send a very simple command, such as turning the servo to the middle position. If it produces action, congratulations, the wiring has been successful. If there is no response, start with the signal line to troubleshoot. Use an oscilloscope or logic analyzer to check whether the control board sends data, and follow the steps to backtrack step by step. Don't panic, most problems are caused by the common ground or the reverse cross-connection of TX and RX.
When encountering a situation where the servo does not respond, the troubleshooting process must be detailed and methodical. Starting to check the signal line is only the first step, and subsequent in-depth exploration needs to be based on the actual situation. For example, after confirming that the control board sends data, check whether the circuit connection is stable and whether there is any looseness or poor contact. Only through such comprehensive and detailed investigation can the problem be found and solved as soon as possible to ensure that the steering gear system can operate normally. Don't panic, most problems arise from the common ground or the reverse TX and RX cross-connection.
I have seen too many people make the same mistake when wiring: connecting the power line of the serial servo to the 5V output of the control board. I thought it would save trouble, but as soon as the power was turned on, the control panel started to smoke. Because the current when the servo is started is too high, the voltage stabilizing chip on the control board cannot handle it at all.
Another common mistake is not sharing the ground. When you supply power to the servo alone, you do not connect the negative pole of the power supply to the GND of the control board. As a result, the signal line has no loop, which causes the servo to malfunction intermittently. ️ Another situation is that the signal lines are connected reversely, for example, TX is connected to the TX position and RX is connected to the RX position. This kind of connection will make the data unable to be transmitted at all. It is important to remember that the communication lines need to be cross-connected, unless of course the servos are already cross-connected internally.
Did you encounter any "surprises" or "shocks" when you first connected the serial servo? Welcome to share your experience in the comment area so that everyone can avoid pitfalls together! If this article helped you, don’t forget to like it and forward it to more friends who need it.
Update Time：2026-03-21
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