Servo drives play a crucial role in precision motion control systems, offering advanced features and capabilities for accurate and efficient motor control. However, understanding the various terminologies associated with servo drives can sometimes be challenging. In this blog, we will explore and explain key terminologies related to servo drives in a simple and concise manner.
Whether you’re new to servo drives or looking to deepen your knowledge, this blog will serve as a helpful resource to demystify the terminology and enhance your understanding of servo drive technology. Let’s dive in and unravel the world of servo drive terminologies!
A
Absolute Encoder
Absolute encoders provide precise position information in servo drives. It generates a unique digital code for each position of the motor shaft. Absolute encoders determine motor position precisely in servo drives without a reference point.
This enables highly accurate and reliable motion control in applications. Where position accuracy is critical.
Alternating Current (AC)
AC powers motors in servo drives as an electrical current type. AC servo motors are commonly used due to their efficient transmission and ease of control. The servo drive converts the incoming AC power into the appropriate form to drive the motor.
AC power ensures precise control of the motor in varied servo motor applications.
Analog Command Input
Analog command input is a method of providing control signals to the servo drive. Analog signals represent control parameters in servo systems through voltage or current. Such as position, velocity, or torque.
The servo drive interprets analog signals to adjust the motor for desired motion or performance. Analog command input provides flexibility and compatibility with various control systems. It is allowing for smooth and precise control of the servo motor.
Analog Feedback PID Control
Analog PID control ensures precise motor performance in servo drives. It involves using analog signals from sensors. Encoders to provide continuous feedback on the motor’s position, velocity, or other parameters.
The PID control algorithm continuously adjusts the motor’s output based on this feedback. It minimizes the error between the desired setpoint and the actual performance.
Analog Inputs
Analog inputs in servo drives allow for the connection of external devices. That provide analog control signals. Current signals command and adjust servo drive parameters like position, speed, or torque.
The servo drive converts analog input signals to digital for processing and control.
Analog Output
Analog output in a servo drive refers to its ability to generate analog voltage. These signals can be used to interface with external devices or systems. It is providing real-time information or control signals.
Analog outputs allow the servo drive to communicate motor status and reference values. Other relevant information to other components or systems in the automation setup.
Armature Inductance (mH)
Armature inductance is the inductance value of an electric motor’s armature winding. It represents the ability of the winding to store energy in the form of a magnetic field. The unit of measurement for armature inductance is millihenries (mH).
Higher armature inductance can affect the motor’s response time and performance. It is leading to slower changes in the current flow.
Armature Resistance (Ohm)
The armature resistance is the electrical resistance of the motor’s armature winding. It represents the opposition to the flow of electric current.
The unit of measurement for armature resistance is ohms (Ω). Higher armature resistance causes power losses and heat generation in the motor.
Asynchronous Motor (Induction Motor)
An asynchronous motor, also known as an induction motor. It is a type of electric motor commonly used in various applications. It operates by creating a rotating magnetic field. That induces current in the rotor, causing it to rotate.
Asynchronous motors are simple and robust. Because they don’t have direct electrical connections between the stator and the rotor. Due to their efficiency, reliability, and load-handling capabilities, asynchronous motors are widely utilized.
Auto-Tuning
Auto-tuning optimizes servo drive performance by adjusting control parameters automatically. Auto-tuning identifies motor and load characteristics through tests or algorithms. Then determine the appropriate control settings such as gains and response times.
Auto-tuning simplifies the setup process. It ensures optimal operation without the need for manual parameter adjustment.
B
Backlash
Backlash is the clearance or play between mechanical components in a system. It represents the amount of movement or lost motion that occurs when a direction change is made. In servo drives, backlash can affect positioning accuracy and introduce errors.
Compensation techniques, such as dead band control or anti-backlash mechanisms. They are employed to minimize the impact of backlash on the system’s performance.
Bandwidth
Servo drive bandwidth is the frequency range. Where the system accurately responds to command signal changes. It represents the ability of the system to follow rapid changes. A wider bandwidth allows for faster response times and better dynamic performance.
Servo drive bandwidth is influenced by the control algorithm, and motor characteristics. And also the mechanical properties of the system. Higher bandwidth is desirable for applications that require precise and fast motion control.
Bode Plot
A Bode plot consists of two plots: one representing the gain of the system. It provides valuable information about the system’s response to different frequencies. The gain plot shows how the output signal amplitude changes with frequency.
While the phase plot shows the time delay or phase shift of the output signal relative to the input signal. By analyzing the Bode plot, engineers can assess the stability and bandwidth.
Brushed Motor
A brushed motor uses a rotating armature, brushes, and commutator for operation. The brushes and commutator supply current to different sections of the armature. Generating the magnetic fields that drive the motor’s rotation.
Brushed motors are relatively simple and cost-effective but have limitations. Drawbacks of brushed motors include lower efficiency and limited lifespan due to brush wear.
Brushless Motor
A brushless motor operates using electronic commutation instead of brushes and a commutator. Brushless motors feature a stationary stator with permanent magnets.
A rotating rotor with electromagnets. Electronics switch stator currents to drive the rotor with a rotating magnetic field.
Brushless motors offer advantages such as higher efficiency, longer lifespan, and quieter operation. It reduced maintenance compared to brush motors. They are commonly used in various industrial, automotive, and consumer applications.
C
CANopen Communication
CANopen is a communication protocol commonly used in industrial automation systems. It is based on the Controller Area Network (CAN) protocol. It provides a standardized way for devices to communicate with each other. CANopen supports reliable and efficient data exchange, device configuration, and network management. Synchronization among various devices in a network.
Clockwise (CW) Direction
Clockwise direction refers to the rotational direction of a motor or mechanical system. In servo drives, clockwise motor rotation aligns with the clock’s hands. When viewed from the drive end. Rotation direction can be controlled based on application requirements in servo drives.
Closed Loop System
A closed-loop system is also known as a feedback control system. It continuously monitors and compares output with desired input in a control system. In the case of servo drives, a closed-loop system uses feedback from sensors, such as encoders.
To continuously adjust the control signals and maintain accurate positioning or speed control. Feedback information corrects deviations between desired and actual system behavior. It ensures precise and stable operation.
Cogging Torque
Cogging torque is the non-uniform torque experienced by a motor during low-speed rotation. It is caused by the interaction between the permanent magnets and the teeth of the motor’s stator.
Cogging torque can result in vibration, noise, and decreased smoothness in motor operation. Various techniques, such as motor design improvements and advanced control algorithms. It is used to minimize or mitigate cogging torque in servo systems
Command Signal
The Command signal is the desired value that the servo system aims for. It represents the target control parameter for the system to follow. The command signal can be generated by a user interface, a motion controller. An external device and serves as the input to the servo drive to guide its operation.
Command Source
The command source refers to the origin or provider of the command signal in a servo system. A Human, control system or PLC can be the command source. Any other device that generates the desired reference values for the servo drive. The command source determines the overall control strategy and influences the behavior. The functionality of the servo system.
Continuous Output Current
Continuous output current is the maximum sustained current delivered by a servo drive. It represents the sustained current level. The drive can provide for extended periods during normal operation. It is an important specification to consider when selecting a servo drive. To ensure it can handle the current requirements of the connected motor.
Control Signals
Control signals regulate motor operation, generated by the servo drive. These signals include commands and feedback signals. The various control parameters that govern the motor’s speed, position, or torque. Control signals are used to adjust the output of the drive. Drive implements control algorithms for desired motor performance.
Cooling Method
The Cooling method dissipates heat generated by the servo drive during operation. It ensures that the drive stays within its acceptable temperature limits prevent overheating.
Common cooling methods for servo drives: convection, forced air (fans), and liquid cooling. The choice of cooling method depends on factors such as the power rating of the drive. The environmental conditions, and the level of heat dissipation required for reliable operation
Counterclockwise (CCW) Direction
Counterclockwise (CCW) direction refers to the rotational direction of the motor or shaft. When it rotates opposite to the clockwise direction. In a servo system, CCW direction is usually considered negative or reverse. While the clockwise (CW) direction is considered the positive direction. Command signals control the direction of rotation in a servo drive.
Current Control (Torque Control)
Current control, or torque control, regulates motor winding current in servo drives. Precise current control manages motor torque in servo drives. To achieve accurate and responsive control of position, speed, or torque. Current control enables the servo system to deliver the desired level of torque to the motor. It is ensuring precise and dynamic performance.
D
Damping
Damping reduces oscillations, vibrations, or overshoots in servo motor motion. Damping is achieved by applying resistive forces or control algorithms that absorb. It dissipates excess energy and promotes smoother motion. Proper damping improves the stability, precision, and settling time of the servo system.
It helps prevent oscillations or unwanted vibrations. It can negatively affect the system’s performance and accuracy.
Deadband
Deadband is a range where no corrective action is taken by servo drive. It allows for a certain amount of tolerance or hysteresis in the control system. It preventing unnecessary adjustments when the measured value is within the deadband range. Deadband helps minimize frequent and unnecessary motor adjustments. It is providing stability and prevents rapid oscillations around the setpoint.
Derating (%)
Derating is a percentage-based reduction in the maximum rated capacity. The performance of a servo drive under specific operating conditions. It is necessary when certain factors, such as ambient temperature, altitude. Power supply limitations can impact the drive’s full-rated capacity delivery.
Derating enables safe and reliable operation within the servo drive’s limits for optimal performance. It considers the given operating conditions.
Digital Input
Digital input refers to an input signal to the servo drive that represents a discrete on or off state. It connects external devices or sensors to provide commands or signals to the drive.
Digital inputs use binary signals: high voltage for “on” and low voltage for “off”. Digital inputs initiate actions and control mode changes for various purposes. Also responding to external events in the servo system.
Digital Output
Digital output signals from the servo drive represent discrete on/off states. It is used to control or activate external devices or components in the system. Digital outputs switch between high and low states with voltage or current signals.
These outputs can be used to drive indicators, relays, and solenoids. Other devices are based on the control logic and program settings.
Direct Current (DC)
Direct current (DC) refers to the flow of electric charge in a single direction. DC power is commonly used in servo drives to provide continuous current flow to the motor. Unlike alternating current (AC), which changes direction periodically.
DC maintains a constant polarity, allowing for consistent and controlled motor operation.
DMCNET
DMCNET is a communication protocol or network used for connecting. It communicates between servo drives and other automation devices in a system. It is a high-speed and deterministic network that enables real-time data exchange.
DMCNET enables precise communication for synchronized motion control in automation applications.
Drive Resolution
Drive resolution is the smallest step size for motor positioning in servo drives. It represents the level of precision and accuracy in controlling the motor’s movement. Drive resolution is typically specified in terms of counts per unit of movement. Such as counts per revolution or counts per millimeter.
Higher drive resolution enables finer and more precise motor control for positioning and velocity.
Duty Cycle
The Duty cycle is the ratio of the maximum rated operating time to the total operating time in a servo drive. The duty cycle represents sustained maximum load time within thermal limits as a percentage.
A 50% duty cycle allows the drive to operate at maximum power for half the total operating time. Duty cycle considerations are important for selecting. It operates the servo drive within its safe operating limits.
E
E-Gear Ratio
E-Gear ratio, also known as electronic gear ratio, is a feature in servo drives. Virtual gear ratio adjustment controls motor speed and torque output. It means achieving different speed reductions. or multiplication factors electronically without the need for physical gear changes.
E-Gear ratio settings enable precise speed control and fine-tuning of the motor’s performance. Allows customized motion profiles for optimized operation in diverse applications.
Electrical Noise
Electrical noise refers to unwanted or undesirable electrical signals or disturbances. That can interfere with the proper functioning of electronic devices or systems. Various factors, including EMI, RFI, and power fluctuations, can cause electrical noise.
Electrical noise can degrade servo drive system performance and disrupt signals and communications. Shielding, filtering, and grounding minimize electrical noise for reliable operation.
Electrical Time Constant
The electrical time constant refers to the time it takes for an electrical circuit. The component reaches 63.2% of steady-state response after sudden input change. The electrical time constant represents the response time of the electrical components. Such as capacitors and inductors, in the drive system.
It influences the dynamic performance and responsiveness of the drive. It is affecting factors such as acceleration, deceleration, and torque control.
Electronic Camming
Electronic camming synchronizes multiple axes/motors using predetermined profiles. It allows for precise coordination and control of movements. Simulating the behavior of mechanical cam systems electronically.
Electronic camming replaces physical cam mechanisms, offering flexibility and adjustability. Commonly used for precise positioning, synchronization, and complex motion patterns.
Electronic Gearing
Electronic gearing synchronizes multiple axes or motors for a specific speed. Enables motor synchronization, creating a master-slave relationship in electronic gearing.
Electronic gearing enables speed control between axes for synchronized motion. Used in robotics, CNC, and packaging for precise synchronized movement of multiple components.
Encoder
Encoder provides motor shaft position, velocity, and direction feedback in servo drives. The Encoder converts the motor’s mechanical motion into interpretable electrical signals for the drive.
Incremental and absolute encoders play a crucial role in closed-loop control systems. It is ensuring accurate and precise positioning.
Encoder Cables
Encoder cables are specialized cables used to connect the encoder to the servo drive. These cables transmit the electrical signals between the encoder and the drive. It ensures reliable and accurate communication.
Encoder cables are designed to minimize signal interference and maintain signal integrity. It allows for high-resolution feedback and precise motor control.
Encoder Type
Encoder type refers to the specific technology or design used in an encoder. Various encoder types exist: optical, magnetic, and capacitive, each with advantages and limitations. Encoder type influences resolution, accuracy, and environmental robustness, impacting servo drive system performance.
EtherCAT Communication
EtherCAT is a high-performance industrial communication protocol widely used in servo drive systems. EtherCAT enables fast and synchronized communication over a single Ethernet cable
EtherCAT enables real-time data exchange, precise servo drive synchronization, and seamless automation integration. EtherCAT provides high-speed transmission, scalability, and flexibility for demanding industrial automation applications.
F
Feed Forward Compensation
Feed-forward compensation enhances dynamic performance in servo drives. Feed-forward compensation anticipates and compensates for disturbances by providing pre-calculated control input.
Feed-forward input is based on the disturbance-output response relationship. It helps to minimize errors and improve tracking accuracy.
Feedback Device
A feedback device, also known as a position feedback device or sensor. Servo drives utilize feedback devices for real-time motor/load position, velocity, Parameter information.
This feedback is essential for closed-loop control. It is allowing the drive to adjust its output based on the actual performance of the system. Common feedback devices include encoders and resolvers.
Field Oriented Control (FOC)
Field Oriented Control (FOC) achieves precise motor control in servo drives. It involves transforming the three-phase motor currents into a rotating reference frame. It is allowing independent control of torque and flux components.
FOC enhances motor performance by decoupling variables for improved control.
G
Gain Adjustment
Gain adjustment, also known as gain tuning or gain setting. It is the process of adjusting the control gains in a servo-drive system. Gains determine the responsiveness and stability of the system. By adjusting gains, the control system optimizes performance as desired.
Proper gain adjustment minimizes overshoot and oscillations for smooth and accurate motor control. Gain adjustment through trial and error or automated tuning for optimal performance.
Gearbox
Gearbox reduces speed or multiplies torque in servo drive systems. Gears transmit power and adjust speed/torque in a gearbox. Gearboxes match motor speed and torque to load requirements in common usage. It is allowing for precise control and improved system performance.
H
Harmonic Distortion
Harmonic distortion is unwanted harmonic components in the servo drive system waveform. Harmonics are frequencies that are integer multiples of the fundamental frequency.
Excessive harmonic distortion causes heating, power quality reduction, and electrical interference issues. Proper filtering and harmonic mitigation techniques are employed to minimize harmonic distortion. It ensures the smooth and efficient operation of the servo drive system.
Home Position
The home position is also known as the reference position or zero position. It is a predefined position in a servo drive system. Where the motor or actuator is considered to be at a known and repeatable state. Reference point enables accurate load position determination in positioning applications. The home position is set as a baseline for subsequent movements during initialization.
Humidity
Humidity refers to the amount of moisture or water vapor present in the surrounding air. Humidity impacts electronic component performance and reliability in servo drive systems. High humidity levels can lead to condensation, corrosion, and insulation degradation. Which may impact the operation of the servo drive system.
Follow the manufacturer’s recommended humidity range and implement sealing and ventilation. It is moisture protection for optimal performance in humid environments.
Hysteresis
Hysteresis is lagging output behind input changes in a system. In the context of servo drives, hysteresis can occur in control algorithms. Mechanical components, resulting in a delay or non-linear response. It can affect the accuracy and stability of position control. Minimizing hysteresis is important to ensure precise and responsive servo motor control.
I
Incremental Encoder
The incremental encoder provides position feedback in servo drive systems. It generates pulses or digital signals as the motor shaft rotates. Which is used to measure the angular displacement and speed. Incremental encoders track relative position changes, unlike absolute encoders providing absolute position information.
They are commonly used for speed control and relative positioning applications.
Inertia
Inertia refers to the resistance of an object to changes in its state of motion. Inertia quantifies mass and mass distribution in the servo drive system’s rotating components.
Inertia affects the responsiveness and dynamic performance of the servo system. It is including acceleration and deceleration capabilities. Balancing inertia between the motor and load is crucial for precise control.
Input Current
Input current refers to the electrical current supplied to the servo drive system. It is the current flowing into the drive from the power source, typically an AC or DC power supply. It determines servo drive power requirements and rating, a crucial parameter to consider.
Input current must stay within specified limits to prevent overload conditions. It ensures safe and reliable operation of the servo drive system.
Input Voltage and Phase
Input voltage and phase determine power supply characteristics in servo drive systems. The input voltage can be AC or DC, and the phase can be single-phase or three-phase. Matching input voltage and phase ensures proper operation and performance of servo drives.
Inrush Current
Inrush current is the initial surge of current that flows into the servo drive system when it is powered on. It occurs due to the charging of capacitors and the energization of components. Consider inrush current during design to prevent power supply and breaker issues.
IP Rating
IP rating, also known as the Ingress Protection rating. IP rating indicates servo drive’s protection against solid objects and liquids. IP rating has two digits, with the first representing solid particle protection. The second digit represents liquid ingress protection.
Higher IP ratings indicate better protection. IP rating determines servo drive suitability for various environments and applications.
L
Limit Switches
Limit switches define the motion limits of the motor in servo drive systems. They are positioned at the endpoints of the desired travel range. It provides feedback signals to the servo drive when the motor reaches the set limits.
Limit switches help prevent overtravel and protect the mechanical components. Used in precise positioning applications requiring motion control and accuracy.
Load Tolerance
Load tolerance is the servo drive’s ability to handle variations in applied load. Load tolerance reflects the servo drive’s stable operation and performance under varying loads. Higher load tolerance allows servo drives to handle a wider load range. While maintaining functionality and accuracy.
M
Max Torque
Max torque, also known as greatest torque, is the highest amount of rotational force that a servo drive can deliver to the motor shaft. It represents the motor’s capability to generate torque at its most capacity.
The max torque specification is important for applications that must have high torque output. Such as heavy-duty or demanding industrial processes.
Max. Instantaneous Current (Arms)
Max. instantaneous current is the peak current that flows through the servo drive. It represents the greatest current level it can handle without exceeding its rating. This specification ensures the drive can handle current spikes without damage.
Maximum Speed (rpm)
Maximum speed refers to the highest rotational speed that a servo drive can achieve. It represents the upper limit of the motor’s rotational velocity in revolutions per minute (rpm).
The maximum speed specification is important for applications that must have high-speed motion or rapid positioning.
Maximum Torque (N-m)
Maximum torque, measured in Newton-meters (N-m), is the highest amount of rotational force that a servo drive can deliver to the motor shaft. It represents the motor’s capability to generate torque at its maximum capacity.
The maximum torque specification is important for applications that require high torque output. Such as lifting heavy loads or performing tasks that require high force.
Mechanical Time Constant (ms)
The mechanical time constant is a parameter that represents the time it takes for the mechanical system. It includes the motor and load, to respond to changes in the applied torque. It indicates the system’s ability to accelerate or decelerate in response to control commands. A shorter time constant equals a faster response. The longer time constant equals a slower response.
Mechanical Time Constant (ms) with Brake
This refers to the mechanical time constant of the system when a brake is applied to the motor. The presence of a brake can affect the system’s response time and overall performance. The mechanical time constant with the brake specifies the time it takes for the system to reach a new steady-state condition when a braking force is applied.
Modbus Communication
Modbus is a widely used communication protocol in industrial automation systems. It facilitates data exchange and controls signal transmission between devices. It operates over serial or Ethernet networks. Modbus enables efficient and reliable communication in the system.
Motion Profile
A motion profile refers to a predefined trajectory or pattern of motion that a servo drive can follow to achieve precise and controlled movement. It includes parameters such as acceleration, deceleration, velocity, and position, which are programmed to ensure smooth and accurate motion control in various applications.
Motor Winding
Motor winding refers to the wire coils present in an electric motor that carry electrical current to produce the magnetic fields necessary for motor operation. The winding configuration, such as the number of turns and the arrangement of coils, affects the motor’s performance characteristics, including speed, torque, and efficiency.
N
Notch Filter
A notch filter is an electronic filter used to suppress or attenuate specific frequencies within a signal. It is often employed to mitigate the effects of unwanted noise or interference that may affect the performance of a servo drive or other electronic systems.
The notch filter selectively reduces the amplitude of a particular frequency or a narrow range of frequencies while allowing other frequencies to pass through unaffected.
O
Open Loop System
An open-loop system refers to a control system where the output of the system is not directly fed back to the input for correction or adjustment. In the context of servo drives, it means that the motor control is based solely on the input commands without feedback from sensors.
Open-loop systems are simpler but may not provide precise positioning or accurate motion control.
Oscilloscope Function
An oscilloscope function is a feature available in some servo drives that allows monitoring and analysis of electrical signals. It displays voltage waveforms graphically on a screen, enabling users to observe and analyze the behavior of the electrical signals in real-time.
This can be useful for diagnosing issues, optimizing performance, and troubleshooting the servo drive system.
Output Pulse Frequency
Output pulse frequency refers to the rate at which pulses are generated by the servo drive’s output signal. It indicates the frequency at which the motor’s position or speed is updated.
The pulse frequency determines the resolution and smoothness of the motor’s motion, with higher frequencies providing finer control and smoother operation.
Overload Capacity
Overload capacity refers to the ability of a servo drive to handle temporary or sustained loads that exceed its rated capacity. It indicates the maximum load that the drive can handle without causing damage or compromising its performance.
Higher overload capacity allows the drive to handle sudden load changes or demanding operating conditions. While maintaining stability and protecting the motor from excessive stress.
Overshoot
Overshoot is the extent to which a system’s response exceeds its desired or target value before settling down. In the context of servo drives, it refers to the deviation of the motor’s position or velocity from the desired position during a motion profile.
Minimizing overshoot is important for achieving accurate and precise positioning.
P
Permissible Voltage
Permissible voltage refers to the acceptable voltage range that a servo drive can safely operate within. It specifies the voltage limits to avoid damage to the drive or connected components. Operating the drive within the permissible voltage range ensures reliable and stable operation.
Phase Margin
Phase margin is a measure of the stability of a control system, including servo drives. It represents the amount of phase difference between the system’s output and input signals at the frequency where the system’s gain is unity. A higher phase margin indicates a more stable system, with better resistance to oscillations or instability.
Position Control
Position control refers to the capability of a servo drive to control the position of a motor. It enables accurate positioning of the motor’s shaft or load at a specific target position.
The servo drive receives position commands and adjusts the motor’s speed and torque to achieve the desired position. Position control is crucial in applications where precise positioning is required. Such as robotics, CNC machines, and automated manufacturing systems.
Power Cables
Power cables are electrical cables used to send electrical power from a power source. Such as a power supply or mains outlet, to the connected equipment. They are designed to handle the specific voltage and current requirements of the devices. They are connected to and ensure a reliable and safe power connection.
Power Indicator
A power indicator is a visual signal, often in the form of an LED light, that indicates the status of the power supply or equipment. It illuminates when power is supplied to the device, providing a visual confirmation of power availability.
Power Supply
A power supply is a device that converts electrical power from a power source into the appropriate voltage and current required to operate electronic devices or systems. In the context of servo drives, a power supply provides the necessary power to drive and control the motor.
PR Mode
PR mode stands for Position Regulation mode. It is a control mode in servo drives where the drive’s primary goal is to regulate the motor’s position and maintain it within a specific tolerance. In PR mode, the servo drive adjusts the motor’s speed and torque to correct any positional errors and keep it aligned with the desired position.
This mode is used in applications that require precise positioning, such as robotics and automation systems.
Proportional-Integral-Derivative (PID) Control
PID control is a feedback control mechanism widely used in servo drives to regulate the motor’s position, speed, or other parameters.
It calculates control signals based on the error between the desired value and the actual value. It takes into account proportional, integral, and derivative terms to achieve stable and accurate control.
Pulse Train
A pulse train refers to a series of discrete pulses that are generated by the servo drive to control the motor’s movement. The frequency, duration, and amplitude of the pulses determine the motor’s speed, direction, and other motion characteristics.
Pulse Type
In the context of servo drives, pulse type refers to the specific format or protocol used to transmit control signals from the drive to the motor. Common pulse types include pulse and direction (P/D), pulse-width modulation (PWM), and step and direction (S/D).
Pulse Width Modulation (PWM)
PWM is a technique used in servo drives to control the power delivered to the motor. It involves rapidly switching the power supply on and off at a variable duty cycle. By adjusting the width of the pulses, the average voltage applied to the motor can be controlled, allowing precise regulation of speed and torque.
Q
Quadrature Inputs
Quadrature inputs refer to a pair of digital signals used in position-sensing applications, particularly in encoders. These inputs are 90 degrees out of phase with each other. It allows for precise measurement of rotational position and direction.
R
Rated Current (Arms)
Rated current, measured in amperes (A), signifies the continuous current capacity of a servo drive or motor. It represents the maximum current that the device can handle within its thermal limits. This specification is vital for ensuring the safe and reliable operation of the equipment.
Rated Power (kW)
Rated power, measured in kilowatts (kW), denotes the continuous power output capability of a servo drive or motor. It indicates the maximum power that the device can deliver without overheating or exceeding its design limits. This specification is essential for selecting the right equipment for specific applications, ensuring optimal performance, and avoiding potential issues.
Rated Power Output
Rated power output is the maximum power that a servo drive or motor can deliver to the load under normal operating conditions. It is typically specified in kilowatts (kW) and indicates the device’s ability to provide the necessary torque and speed for a given application.
The rated power output is an important parameter for selecting the appropriate servo system for a particular task.
Rated Power Rate (kW/s)
The rated power rate, measured in kilowatts per second (kW/s), represents the rate at which the power output of a servo drive or motor can change over time. It indicates the device’s ability to handle dynamic load changes and acceleration/deceleration scenarios.
Rated Power Rate (kW/s) with Brake
The rated power rate with brake refers to the maximum rate at which the power output of a servo drive or motor. It includes the braking capability, can change over time. It takes into account the additional power dissipation and control during braking operations.
Rated Speed (rpm)
Rated speed is the maximum rotational speed at which a servo motor or drive can operate continuously without exceeding its design limits. It is usually measured in revolutions per minute (rpm) and represents the motor’s capability to deliver the specified speed for a given load.
Rated Torque (N-m)
Rated torque is the maximum continuous torque output that a servo motor or drive can provide without exceeding its thermal limits. It is measured in Newton meters (N-m) and represents the motor’s ability to deliver the specified torque at the rated speed.
Regenerative Resistor
A regenerative resistor is an electrical component used in servo drives to dissipate excess regenerative energy generated during deceleration or braking. It helps prevent overvoltage conditions in the drive system by converting the excess energy into heat.
Resolver
A resolver is a type of position sensor commonly used in servo systems to provide accurate feedback on the rotor position. It operates based on electromagnetic induction principles and can determine both the angular position and speed of a rotating shaft.
Resonance
Resonance refers to a phenomenon in which a mechanical or electrical system exhibits a high-amplitude response to an input signal at its natural frequency. In servo drives, resonance can lead to instability and vibration, affecting the performance and accuracy of the system.
Rotational Inertia
Rotational inertia, also known as moment of inertia, is a measure of an object’s resistance to changes in rotational motion. In servo systems, it represents the mass distribution and geometry of rotating components. Such as motors and loads, and affects the system’s response time and torque requirements.
Rotor Inertia
Rotor inertia refers to the resistance of a rotating component, such as a motor rotor, to changes in its rotational motion. It represents the mass and distribution of the rotor and affects the servo system’s response and acceleration characteristics.
S
Safe Torque Off (STO) Function
Safe Torque Off (STO) is a crucial safety function in servo drives. When activated, it instantly stops the motor’s torque output. STO ensures swift and secure motor stoppage during emergencies or maintenance. It prevents accidental movements and minimizes the risk of accidents.
Servo Drive
A servo drive, also known as a servo amplifier, is an electronic device that provides the necessary power and control signals to drive and control a servo motor. It receives commands from the control system and adjusts the motor’s voltage, current, and speed to achieve precise motion control.
Servo Motor
A servo motor is a type of motor designed for high-precision motion control applications. It converts electrical energy into mechanical motion with high accuracy and responsiveness. Servo motors typically have built-in position feedback devices, such as encoders, for precise control and feedback.
Settling Time
Settling time is the time it takes for a system to reach a stable state after a change in input or desired output. In the context of servo drives, it refers to the time required for the motor to reach and settle at the desired position, velocity, or torque after a command is given.
Sine Wave Control
Sine wave control is a control method used in servo drives to generate smooth and precise motor motion. It involves modulating the motor’s current or voltage in a sinusoidal pattern to achieve accurate speed and position control.
Single-Phase Power
Single-phase power refers to a type of electrical power distribution that utilizes a single alternating current (AC) waveform. It is commonly used in residential and small-scale applications. In the context of servo drives, it refers to the type of power supply used to provide electrical energy to the drive and motor.
Slew Rate
Slew rate refers to the rate of change of a signal over time. In servo drives, it refers to the maximum rate at which the motor’s speed or position can change. It indicates the motor’s ability to accelerate or decelerate quickly and is an important parameter for achieving smooth and precise motion control.
Smoothing Method
The smoothing method refers to the technique used to reduce or eliminate fluctuations or variations in the output signal of a servo drive. It helps to achieve smoother and more stable motor motion by minimizing abrupt changes or oscillations.
Speed (RPM – Revolutions per Minute)
Speed is a measure of how fast the motor shaft rotates and is typically expressed in revolutions per minute (RPM). It indicates the rate of motion of the motor and is a crucial parameter for controlling and monitoring the motor’s rotational speed.
Speed Calibration Ratio
The speed calibration ratio is a factor used to adjust or calibrate the speed output of a servo drive. It ensures that the motor’s actual speed matches the desired or commanded speed accurately.
Speed Capture Function
Speed capture function is a feature in servo drives that allows the measurement and recording of the motor’s rotational speed. It enables real-time monitoring and feedback of the motor’s speed for precise control and performance analysis.
Speed Control Range
Speed control range refers to the range of speeds over which a servo drive can accurately control the motor’s rotational speed. It represents the minimum and maximum speed values within which the servo drive can maintain precise speed control.
Stability
Stability in the context of servo drives refers to the ability of the system to maintain steady and consistent motor performance without oscillations or instabilities. A stable servo drive ensures smooth and reliable operation of the motor under varying load conditions.
Step and Direction Inputs
Step and direction inputs are control signals used to command the motion of a servo motor. The step input provides discrete step commands to control the motor’s position or speed, while the direction input determines the direction of motion (clockwise or counterclockwise).
Synchronous Motor
A synchronous motor is a type of motor that operates at a fixed speed synchronized with the frequency of the power supply. It uses permanent magnets or electromagnetic fields to create a rotating magnetic field, resulting in precise speed control and high efficiency.
Synchronous motors are commonly used in applications requiring accurate speed synchronization and control.
T
Three-Phase Power
Three-phase power refers to an electrical power supply system that uses three alternating currents with a phase difference of 120 degrees. It is commonly used in industrial applications to deliver higher power capacity and efficiency compared to single-phase power.
Torque
Torque is the rotational force exerted by a motor or drive system. It determines the motor’s ability to generate rotational motion and is measured in units of force multiplied by distance (e.g., N-m).
Torque Constant (KT)
The torque constant (KT) is a parameter that relates the motor’s torque output to the electrical current flowing through it. It indicates how much torque the motor can produce per unit of current and is measured in units of N-m/A.
Torque Feature (T-N Curve)
The torque feature, often represented as the T-N curve, describes the relationship between the motor’s torque output and its rotational speed (N). It shows how the motor’s torque capability varies at different speeds, providing valuable information for selecting the appropriate motor for a specific application.
Torque Limit
A torque limit is a setting that restricts the maximum amount of torque that a servo drive or motor can produce. It is used to prevent excessive torque that may damage the system or cause instability.
Trajectory Planning
Trajectory planning is the process of determining the desired path or motion profile for a servo system. It involves defining the acceleration, deceleration, and velocity profiles to achieve smooth and precise movement of the motor.
Tuning
Tuning refers to the process of adjusting the control parameters of a servo drive or motor to optimize its performance. It involves fine-tuning the proportional, integral, and derivative (PID) gains to achieve the desired response and stability.
Tuning Mode
Tuning mode is a specific operating mode of a servo drive or motor that enables the user to adjust the control parameters or perform automatic tuning procedures. It provides a dedicated interface or functionality for the tuning process.
U
USB Cables
USB cables, or Universal Serial Bus cables, are indispensable tools for connecting devices in the digital age. They establish reliable and versatile connections, facilitating data transfer, charging, and peripheral connectivity. USB cables come in various types and versions, each with distinct features.
USB cables also support power delivery, enabling devices to charge. With their widespread compatibility and convenience, USB cables have become a standard connection method in various applications. From smartphones and tablets to computers, printers, and other electronic devices.
V
Velocity Control
Velocity control is a method used in servo drives or motors to precisely control the speed of motion. It allows the user to set and maintain a specific velocity or speed profile for accurate and controlled movement.
Vibration
Vibration refers to the oscillating or shaking movement of an object or component. In the context of servo drives or motors, vibration can impact the performance and stability of the system. Proper vibration control measures, such as mechanical damping or vibration isolation, may be employed to cut unwanted vibrations.
Vibration Capacity
It is an important consideration when selecting components or devices for applications subjected to vibration. It refers to the ability of a device to withstand and operate under vibrating conditions. Components with higher vibration capacity are designed to handle vibrations without experiencing performance degradation or failure.
Vibration Level (μm)
The vibration level is a measure of the magnitude of vibrations in micrometers (μm). It indicates the amplitude or extent of movement or oscillation of a component or structure. The vibration level helps check the severity of vibrations and assess their potential impact on the performance and reliability of the system.
Lower vibration levels indicate less movement and smoother operation. While higher levels may indicate excessive vibrations that can lead to issues. Such as component wear, noise, or reduced precision.
Voltage Constant -KE (mV/(rpm))
The voltage constant (KE) is a parameter used to describe the relationship between the voltage output of a motor and its rotational speed. It is typically expressed in millivolts per revolution per minute (mV/(rpm)). The voltage constant helps determine the motor’s response to changes in speed and provides a basis for motor control.
The voltage constant provides crucial information for engineers to effectively control and regulate motor speed. By manipulating the applied voltage based on this constant. They can achieve precise control over the motor’s performance and optimize efficiency. Understanding the voltage constant is essential for designing motor control systems. That meet specific performance requirements and deliver optimal results.
Conclusion
Understanding servo-drive terminologies is essential for effectively working with and harnessing the power of servo-drive technology. By familiarizing yourself with these terminologies, you can better navigate the complexities of servo drive systems, optimize motor control, and troubleshoot any issues that may arise.
We hope this blog has provided you with valuable insights into the key terminologies associated with servo drives. Remember, continuous learning and staying up-to-date with the latest advancements in servo drive technology will empower you to tackle new challenges and unlock the full potential of your motion control applications. Keep exploring, experimenting, and applying your knowledge to drive innovation and achieve precision in your projects.