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The positional accuracy of a stepper motor is about 3‑5% of the step angle, and it does not accumulate errors.
Excessive temperature can demagnetise the magnetic material, reducing torque and causing step loss. The demagnetisation point is generally above 130°C, some up to 200°C. Therefore, a surface temperature of 80‑90°C is perfectly normal for a stepper motor. The most common insulation class is Class B, with a rated operating temperature up to 130°C.
When the motor rotates, the inductance in each phase winding generates a back‑EMF. The higher the frequency, the greater the back‑EMF, which reduces the phase current and thus lowers the torque.
This is due to the motor’s pull‑in rate – the maximum pulse frequency at which it can start from standstill without losing steps. If the pulse frequency exceeds this rate, the motor cannot start properly and may lose steps or stall. The solution is to use an acceleration ramp: start at a low frequency and gradually increase to the target high frequency. Integrated stepper motors allow you to set acceleration and deceleration parameters freely.
Microstepping is essentially an electronic damping technique, primarily designed to reduce or eliminate low‑frequency vibration. Improved positional resolution is a secondary benefit. Different manufacturers’ microstepping drivers can vary greatly in accuracy, and higher microstepping numbers are harder to control precisely.
1. Functions and precautions (1) Function description: The power limit function ensures that the output power of the motor does not exceed the rated power, so that the motor can run continuously and stably. This document describes how to use the power limit function of the motor. (2) Precautions: The specific details are subject to the actual situation. II. Function Setting Introduction (1) When bit0-bit14 of H2000-24(H0082) is 0, it means that the power limit function is not turned on; (2) When bit0-bit14 of H2000-24(H0082) is ≠ 0, it means that the power limit function is turned on, and its value is set to the torque value that can be output at 1 times the rated current at low speed; (3) The setting value of rated power H2000-08(H0064) is the maximum power that can be output after the power limit is turned on; (4) The highest bit (bit15) of H2000-24(H0082) indicates whether the power limit alarm function is turned on, 0 is off, 1 is on; after turning on, the motor will report a power limit fault in the power limit state. The power limit alarm function is turned off by default. 3. Example If the power limit is set to 40W, set H2000-08(H0064)=4 (indicates 40W) in the object dictionary; if the torque value of 1 times the rated current output in the measured torque-frequency curve is 0.77Nm (refer to the torque value near 100rpm in the characteristics), then set H2000-24(H0082)=77 (indicates 0.77Nm), so the motor has enabled the power limit of 40W. If you want to enable the power limit alarm at this time, you need to set H2000-24(H0082)=32845 (1000 0000 0100 1101), and the motor will issue a power limit alarm in the power limit state.
In integrated motor products, a switch can be used to control the motor to a fixed speed, applicable to scenarios such as labeling machines. The configuration method is as follows: 1. Enter Hardware Configuration -> IO Configuration interface; 2. Set DI1 to "1-Enable"; 3. Enter Motion Configuration -> Mode Configuration interface; 4. Switch the mode to: "Manufacturer Mode -> 2-Nimotion Speed Mode"; 5. Change "Main Speed Command A Source" to "0-Digital Input", and change "Speed Command Selection" to "0-Main Speed Input"; 6. Modify the three values shown in the image below as needed. They represent speed, acceleration, and deceleration, in rpm; 7. Click "Save All User Parameters" in the lower left corner. After successful saving, power on the motor. Triggering DI1 will allow the motor to be controlled at a fixed speed with a single button.
Modbus TCP is an industrial communication protocol based on TCP/IP. It plays an important role in industrial automation, building automation, energy management, Internet of Things and remote monitoring. The following are the main features of Modbus TCP: I. Protocol Advantages 1. Openness and Standardization The Modbus TCP protocol is based on the TCP/IP protocol stack, which enables it to support cross-platform communication, has strong compatibility, and can be seamlessly integrated into the existing network infrastructure. The specification of the protocol is free and license-free, which promotes the formation of a huge device and software ecosystem and provides users with rich choices. 2. Simple and efficient The function code set of the Modbus TCP protocol is small and well-defined, and the data model is simple, which makes the development threshold relatively low and suitable for rapid deployment. It supports the master-slave communication mode, where the master station initiates the request and the slave station responds. This communication mode reduces processing overhead and improves communication efficiency. 3. Reliable With the reliability mechanism of the TCP protocol (such as data retransmission and flow control), the Modbus TCP protocol can ensure the accuracy and integrity of data transmission. It uses port 502 by default and supports concurrent connection of multiple devices, further enhancing the stability and reliability of the system. 4. High scalability The Modbus TCP protocol supports large address space and broadcast function, which makes it suitable for large-scale industrial networks. It is compatible with various network topologies such as star and bus, and can support complex industrial environments. 2. Protocol structure The structure of the Modbus TCP protocol mainly includes two parts: MBAP message header and PDU (protocol data unit): MBAP message header: 7-byte structure, including transaction identifier, protocol identifier (fixed to 0x0000), length (PDU length) and unit identifier (slave address). It is used to manage request and response matching in TCP connection. PDU: consistent with Modbus RTU, including function code (such as 0x03 read holding register, 0x10 write multiple registers) and data field. The data format is compact and supports bit registers (coils, discrete inputs) and word registers (input/holding registers). 3. Data transmission characteristics 1. High speed and low latency Using the high bandwidth of Ethernet (100 Mbps+), the transmission speed of Modbus TCP protocol far exceeds that of serial protocol (such as 115200 bps of Modbus RTU). It supports real-time data acquisition and control, which is very suitable for the real-time requirements of industrial scenarios. 2. Insufficient security In the early design stage, Modbus TCP protocol did not consider encryption and authentication, which made data easy to be intercepted or tampered. Therefore, in actual applications, it is necessary to rely on external security measures (such as VPN, TLS) to enhance security. 4. Typical application scenarios Modbus TCP protocol has a wide range of applications in many fields: Industrial automation: Connect PLC, sensors, inverters and other equipment to achieve data acquisition and control. Building automation: Integrate HVAC, lighting, access control systems to improve intelligent management capabilities. Energy management: Monitor power equipment, sub-meter data, and optimize energy use strategies. IoT and remote monitoring: Remote access and management of device status through the cloud or local server. V. Limitations Despite the many advantages of the Modbus TCP protocol, it also has some limitations: Limited functionality: Only request/response mode is supported, and expansion is required for complex communications (such as real-time event notifications). Inconvenient configuration: Automatic device discovery is not supported, and new devices need to be manually configured with IP and port. Network performance limitations: TCP congestion control may cause latency issues in long-distance or high-load scenarios. VI. Comparison with other protocols Compared with the Modbus RTU protocol, the Modbus TCP protocol differs in the following aspects: Physical layer: RTU is based on serial port (RS-485), while TCP is based on Ethernet. Reliability: RTU relies on CRC check, while TCP relies on TCP/IP mechanism. Applicable scenarios: RTU is suitable for short-distance, high-interference environments; TCP is suitable for long-distance, large-scale networks. In summary, the Modbus TCP protocol has occupied a mainstream position in the field of industrial automation with its openness, efficiency and compatibility. Despite limitations such as insufficient security, it can still meet the needs of most industrial scenarios by combining encryption technology or industrial Ethernet optimization.
Yes. In the IEC standard, the DC upper limit of SELV (safety extra-low voltage) is **60V**. A 48V battery pack fully charged is about 54.6V (13-series ternary lithium) or 58.4V (16-series LiFePO4), still within the SELV range. Therefore, 48V is in the same safety class as 24V, yet can halve the current.
Highly overlapping. A DD motor (Direct Drive Motor) is named from the **application method**, while a torque motor is named from the **output characteristics**. The vast majority of DD motors on the market are torque motors. The difference is integration: some DD motors are **finished products with housing, bearings, and encoder**, while a "frameless torque motor" is a bare motor that the user must integrate.
They cannot simply be compared by size. IP65 = dust-tight + protection against water jets from any direction; IP67 = dust-tight + immersion in 1 meter of water for 30 minutes. **An IP67 device has not been spray-tested**, so hosing it with a water jet may let water in; an IP65 device withstands jets but fails when soaked. The choice depends on the actual environment: rain/washing → IP65; immersion/flooding → IP67; both possible → must satisfy IP65 + IP67 simultaneously.
Dust-tight + **continuous immersion**, but the **depth and time of immersion are specified by the manufacturer** (not uniformly defined by the standard). So when you see an IP68 rating, you must check the specific depth and time conditions written in the manufacturer's documentation; otherwise the rating has no practical meaning.
It protects against close-range **high-pressure, high-temperature water jets**. It is mainly used where high-pressure hot water washing is required — **CIP in-place cleaning in food and beverage processing, pharmaceutical equipment, chemical equipment**. It is the highest protection rating requirement for electrical equipment in the food and pharmaceutical industries.
Three cases: ① high speed needed (> 1500 rpm) — the torque motor's speed range is limited; ② limited budget with many axes — system cost is higher than servo + gearbox; ③ insufficient mechanical design and assembly capability — a frameless motor requires the user to integrate bearings, housing, encoder, and heat dissipation themselves, and improper integration can cause severe performance degradation or even damage. --- **Further Reading** - [Servo Motor vs Stepper Motor: 7-Dimension Deep Comparison](./01_伺服电机和步进电机的区别_en.md) - [Planetary Gearbox Working Principle and Selection: Reduction Ratio, Backlash and Inertia Matching](../04_传动与反馈/16_行星减速机原理与选型_en.md) - [What Is an Integrated Servo Motor? Drive-in-One Structure, Advantages and Selection](../02_一体化与小型化/07_一体化伺服电机驱控一体_en.md)
Servo is more accurate, and it is "guaranteed accuracy." A stepper's resolution can be made very fine with microstepping, but that is a theoretical open-loop value — once steps are lost, the error accumulates permanently. A servo's accuracy is guaranteed by encoder resolution and the closed loop: a 17-bit encoder provides 131072 positions per revolution, and every position is verified in real time.
At the same power and speed, a servo motor (permanent-magnet synchronous) has significantly higher torque density than an induction motor — because the permanent magnet provides excitation, no excitation current is drawn from the grid, so both power factor and efficiency are higher, and rotor losses are small. In applications requiring frequent start/stop and acceleration/deceleration, the servo's dynamic response and low-speed high-torque output advantages are especially obvious. The induction motor's advantages are high power, low cost, and adaptability to harsh environments.
Integrated low-voltage servos usually cover 50W–750W, with a few reaching the 1kW level. Above 1kW, they generally switch to AC 220V or a higher DC bus (e.g., 310V DC). The limiting factor is mainly current — 1kW at 48V already draws about 21A, and the cost of cables and power devices begins to exceed the benefit of boosting the voltage.
Yes, you must recalculate. After adding a gearbox, the load inertia reflected to the motor shaft must be **divided by i²** (with i = 5 it drops to 1/25), but **the gearbox's own inertia must also be included**. Correct formula: load inertia ratio = (J<sub>load</sub>/i² + J<sub>gearbox</sub>) / J<sub>motor</sub>. Usually the inertia ratio improves dramatically after adding a gearbox — this is the core reason planetary gearboxes are widely used in servo systems. --- **Further Reading** - [Servo Motor Selection Step-by-Step: From Load Torque to Inertia Matching](../01_选型对比/02_伺服电机选型步骤详解_en.md) - [Complete Guide to Servo Motor Encoders: Incremental/Absolute, Single-Turn/Multi-Turn](./17_伺服电机编码器全解_en.md) - [Integrated Leadscrew Motor (Leadscrew Stepper Motor) Selection Guide](./18_一体化丝杆电机选型_en.md)
On conventional performance indicators in the mainstream power range (100W–5kW) — torque accuracy, speed fluctuation rate, speed loop bandwidth, control cycle — leading domestic brands have approached the level of mainstream foreign brands. Taking HCFA as an example, its servo system uses a self-developed encoder, and its torque accuracy, speed fluctuation rate, speed loop bandwidth and control cycle are overall close to comparable products from mainstream foreign brands. The remaining gap lies mainly in long-term reliability data accumulation under extreme conditions, ultra-high-precision applications, and a globalized service system.
Five paths: ① drive-in-one integration (saves the driver and encoder cable); ② increasing power density (high-performance magnets, flat-wire windings, fractional-slot concentrated windings); ③ low-voltage design (24/48V, saves safety clearances and power supply modules); ④ bus-based wiring reduction (all axes share one bus); ⑤ co-design of structure and heat dissipation (housing as heatsink, loss reduction, direct drive topology). The vast majority of successful cases are the result of **combining multiple paths**.
