Currently, most domestic multi-turn absolute encoders require batteries for data retention, commonly referred to as "pseudo multi-turn absolute encoders." Genuine multi-turn absolute encoders are rare in China due to intellectual property constraints and manufacturing stability issues that need further improvement.
We extensively use battery-backed multi-turn absolute encoders. However, when the battery runs out, it must be replaced, leading to a series of challenges. A client inquired about the battery replacement method for the domestic multi-turn absolute encoders used in our TEC steering wheels. Providing solutions to clients is a core aspect of our service philosophy. Without hesitation: consider it done.
Periodic Maintenance and Replacement Method
This method involves proactively replacing the battery with residual power during regular maintenance. Typically, the battery can last around two years. Therefore, a replacement schedule of once per year can be incorporated into the maintenance routine.
1.Before replacement, rotate all the steering wheels on the AGV to the zero position and power down the system.
2.Replace the old battery with a new one.
3.Power up the system and perform a "position loop pulse error reset" on the drive unit to recalibrate the zero position. As shown in the image below, click the red-framed option twice.
4.Note: Different drives have varying zero-calibration methods. Refer to the drive's manual for specific instructions.
Emergency Maintenance and Replacement Method
This method applies when unexpected issues occur, such as battery disconnection or depletion during AGV operation. These scenarios require urgent replacement procedures.
1.Rotate the steering wheel with the affected battery to the home/zero position and then power down the system.
Even if the steering wheel has a home/zero position detection switch, manually confirm accurate placement due to potential sensor errors.
2.Reconnect the disconnected battery wire or replace the depleted battery with a new one.
3.Power up the system and perform a "position loop pulse error reset" on the drive unit to recalibrate the zero position.
Compensating for Limitations of Domestic "Pseudo Multi-turn Encoders" with Enhanced Control Programs
Domestic multi-turn absolute encoders often have limited single-turn counts, capable of measuring only a few degrees to tens of degrees-far from the 180 degrees or more required by various TEC steering wheels. To address this, multi-turn encoders with battery-backed memory are commonly chosen due to cost considerations. However, their drawbacks, such as losing memory when the battery disconnects or depletes, can cause the steering wheel to malfunction. Fortunately, we have robust technical solutions to prevent such emergencies.
1.Drive Retains Memory with Power: As long as the drive has power, it can retain the steering wheel's angle regardless of the battery's status.
2.Critical Loss Point Identified: The angle data is only lost when the battery disconnects or depletes during shutdown. With this in mind, solutions become straightforward:
·Add Self-Diagnostic Program at Startup: Implement a program that detects and alerts if any steering wheel is not at the zero position during startup, specifying the affected wheel.
·Implement Auto-Zeroing Program at Shutdown: Before shutdown, automatically return the steering wheel to the zero position. If an issue occurs, the system can prompt users to check the battery connection or replace the battery, significantly improving AGV reliability and maintenance simplicity.
3.Handling Encoder or Motor Damage: If the drive or motor malfunctions, manual zero-calibration will be necessary.
However, a countermeasure exists: Upload and save the encoder's data to the upper computer before each shutdown or after a fault. Compare it with the data read during the next startup. Additionally, the zero-calibration operation can be integrated into the touchscreen interface, enabling different zeroing procedures for various scenarios, simplifying user operations.
Conclusion
This article introduced two common methods for replacing batteries in domestic multi-turn absolute encoders used in steering wheels and outlined ways to optimize upper computer programs. As engineers, we excel at both modular work handling and layered program design. However, specific issues must always be addressed with tailored solutions. Avoid applying or interpreting the content herein in a rigid or fragmented manner for your reference.
