Capabilities

Output power ranges from 20W to 40kW and we have everything in between including many voltage and current options.

We strive to be compatible with every servo motor available. This makes it easy for our customers to choose the motor they like and run with a superior drive.

With the rapid changes in feedback technology we have kept up by desiging drives that are compatible.

Many controllers require that the drive be in a particular mode. We offer drives that are mode selectible between current, velocity and position modes.

The industry Standard of +/-10V command signals is shifting to digital technology. See how we offer the full range of options.

There are many network solutions out there to choose from. See what AMC has to offer.

AMC software is intuitive and easy to use. Check out the configuration software for RS232, CANopen and SynqNet drives.

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To increase efficiency, all AMC drives use switching type outputs to control power to the motor. Switching drives produce less heat than linear drives and can be built to smaller sizes without sacrificing the output power. Most AMC drives switch around 20kHz. Some of our drives switch up to 50kHz which can be increased to 80kHz upon request.

Pulse Width Modulation (PWM)

Pulse Width Modulation (PWM) is an industry standard that was developed when most drives were controlled with analog control loops. Advanced Motion Controls uses this type of modulation on all analog architecture drives. The switching frequency is set internal to the drive. The duty cycle is actively controlled by comparing the commanded current with the actual current . Two sub-schemes within this category are 0-100% and 50-50 type switching. PWM modulation can be used to power single phase and three phase motors and commutate trapezoidally and sinusoidally.

Space Vector Modulation (SVM)

Space Vector Modulation (SVM) is a switching scheme that is more easily incorporated into digital processor based drives. SVM has the additional benefit of increasing the bus voltage utilization by 15 percent. AMC digital drives use SVM switching.

Motors produce their torque (or force) by pitting magnetic fields against each other. In brushed and brushless motors, one of these two fields is usually produced by permanent magnets, the other by electro magnetic coils. In order for a motor to produce optimum output, these fields must maintain 90 electrical degrees of separation. Commutation is the process by which the current being supplied to a motor is selectively driven through particular coils, so that the generated magnetic field follows the permanent magnetic field as the motor moves. This allows the optimum torque (or force) to be maintained.

Three phase loads can be commutated either trapezoidally or sinusoidally. For Advanced Motion Controls, trapezoidal commutation is associated with our analog products and sinusoidal commutation is associated with digital. Single phase loads such as brushed motors and voice coils either self commutate or do not require commutation.

Trapezoidal

(6-step)

At AMC, Analog three phase drives are commutated trapezoidally. With this type of commutation, current only travels through two of the phases at any given time. This is where the term DC brushless comes from. Trapezoidal commutation provides excellent and cost effective performance for most applications.

Sinusoidal

Sinusoidal commutation smoothly transitions the motor phase currents between all three motor phases. This results in smother response for the most sensitive applications. All AMC digital drives use sinusoidal commutation.

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Current Loop

These drives can achieve a current loop bandwidth of 2.5 kHz depending on the power supply voltage and load inductance. With a 50 microsecond current loop, most AMC Digiflex drives update the current loop 20 thousand times per second.

Velocity Loop

100 microsecond velocity loop update. Most AMC Digiflex drives update the velocity loop 10 thousand times per second.

Position Loop

100 microsecond position loop update. Most AMC Digiflex drives update the position loop 10 thousand times per second.

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Analog drives use analog components which by nature continuously monitor their control parameters. Therefore there is no 'update time' associated with analog drives and the performance of analog drives is limited by how well the control loops are tuned. Precisely tuning the current loop for an application is more time consuming compared with digital drives but the final result can be performance that is unmatched by any digital drive out there.

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A multitude of input and output functions are available. Dedicated and programmable inputs and outputs facilitate drive control, monitoring and diagnostics.

Dedicated Inputs

The most widely used dedicated input is the Inhibit. This removes all output power to the motor to stop motion either for routine shutdowns or for e-stop conditions.

Dedicated Outputs

The most widely used dedicated output is the Fault Out. This output indicates that the drive is experiencing a fault condition. AMC drives also have other dedicated outputs such as the Current Monitor and Velocity Monitor.

Programmable Inputs

Many Programmable Inputs are available to monitor analog and digital signals such as motor temperature, limit switches and other sensors.

Programmable Outputs

There are over 40 signals that can be mapped to the programmable outputs such as motor current, motor voltage, position, fault conditions, and more.

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The two parameters that determine power are Current and Voltage. Torque is proportional to current, and speed is (indirectly) proportional to voltage. Therefore a drive must be selected that can provide enough voltage and current to meet or exceed the application speed and torque requirements.

Our product line covers a wide range of power to meet every need. There are many combinations of voltage and current to choose from. This allows our customers to choose drives that more closely match the required power range and therefore save on system cost.

Current

Motor torque is proportional to the current, therefore it is important to select a drive that will output enough current to achieve the required torque. We have drives that output as little as 1A continuous and others that output 120A peak. We also have products that cover everything in between. The current ratings on our drives are roughly grouped around common values although other current ratings are interspersed throughout. The most common peak ratings are 12A, 20A, 25A, 30A, 60A and 100A. The continuous ratings are typically 1/2 the peak rating. The current limit is usually easy to adjust to more closely match your motor.

Voltage

Motor speed is proportional to the voltage, therefore it is important to select a drive that will output enough voltage to achieve the required speed. The voltage range on our drives goes from a minimum of 16VDC to a maximum of 800VDC. Again we have drives that cover everything in between. The typical voltage ratings include but are not limited to: 20-80VDC, 40-190VDC, 60-400VDC, 30-125VAC, 40-270VAC and 150-480VAC. As you can see, depending on the drive the input voltage can be AC or DC.

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Here at Advanced Motion Controls we are experts at getting our drives to work with your motor. Our drives are so adaptable they can easily outperform packaged motor/drive solutions from other companies with little additional set up time.

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Single phase motors have two power wires and are very easy to set up. Motors in this category can include brushed motors, inductive loads and voice coils. Amplifiers designed for brushed motors are typically used to drive single phase loads although, most three phase drives from AMC can also operate with single phase.

Brush

The brushes in brushed motors are used for mechanical commutation as opposed to electronic commutation found in three phase brushless motors. Simplified installation and low cost are the main advantages. Disadvantages include increased maintenance due to brush wear, lower power density compared with brushless motors and lower heat dissipation since the coils are embedded more deeply into the motor than brushless motors.

Linear Actuator

Linear actuators use a rotary motor coupled to a gear box to move a linear shaft in and out.  The motor in the actuator is often times a brushed motor.

Voice Coil

A voice coil is conceptually similar to an audio speaker. Motion is linear and is usually limited to less than 0.5" (13mm) of travel. Many voice coil applications require a high performance servo drive and Advanced Motion Controls is often the first choice.

Magnetic Bearing

Magnetic bearings are used when low friction is required or when the shaft speeds are too high for conventional bearings. Magnetic bearings use electromagnets to levitate the rotating shaft so nothing is physically touching it. A typical magnetic bearing system will require 4 or 5 drives - an x and y on each side of the rotating shaft and an optional thrust bearing to keep the shaft from floating in and out. The performance requirements for the drives can be extremely high due to the dynamic nature of the system.

Inductive Load

Inductive loads are often used by universities and scientists to create magnetic fields for their experiments. Advanced Motion Controls drives have successfully controlled inductive loads with less than 80uH of inductance to over 1H (1000000uH) of inductance. There are special considerations for the energy stored in a large inductor, and our technical support department would be happy to discuss these regarding your project.

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Three phase loads can be commutated either trapezoidally or sinusoidally. For Advanced Motion Controls, trapezoidal commutation is associated with our analog products and sinusoidal commutation is associated with digital.

Brushless Rotary

Permanent magnet brushless servo motors have higher power density, better heat dissipation and require less maintenance than brushed motors. Brushless motors may be a little more difficult to set up due to the increased wiring so our digital line makes things easier by automating the commutation process.

Linear

The construction of a linear motor is the same as a rotary motor but opened up and flattened out. Configuring a drive for a linear motor is identical to configuring a drive for a rotary motor. Linear motors are used in direct drive applications where the speed and accuracy requirements are more than a rotary motor and ball screw can provide.

Framed

Stand alone motor built with an enclosure body. The majority of motors are framed.

Frameless

Motor built without a housing, intended to be integrated into a machine that will act as the housing.

Solenoid

A simple ON/OFF type motor with limited range. These are driven 'open loop' into the fully extended and retracted positions. Technically this is not considered a servo application but AMC drives can operate these nonetheless.

Solenoid Valve

A solenoid controlled valve that regulates the flow of a fluid.

AC Induction Motor*

Also known as a squirrel cage motor. An AC induction motor consists of windings on the stator and a squirrel-cage-construction rotor that is electrically isolated from the windings. The windings are supplied with 3-phase AC current, and as a result, a rotating magnetic field is produced. The rotating magnetic field causes current to flow in the squirrel-cage rotor which, in turn, creates its own magnetic field. The interaction of these two magnetic fields is what creates torque in the motor.

Vector Motor*

An AC induction motor intended for variable speeds and constant torque even at a near stop.

Spindle Motor

A high speed high torque motor usually coupled to a cutting tool in machining applications.

Variable Reluctance Motor*

Also known as a switched reluctance motor. A very simple motor with a rotor surrounded by a stator consisting of phase coils. This type of motor has the advantage of being capable of very high speeds and low inertia. Industrial applications are limited at this time but may become more prominent as research continues.

Stepper Motor*

Stepper motors are permanent magnate motors with many poles. These motors favor specific positions or 'steps' at each pole. A typical step size is 1.8 degrees or 200 steps per revolution. To increase angular resolution, stepper drivers can 'micro-step' the motor to intermediate step positions. 256 micro-steps per full step is fairly common. Since these motors are driven open loop they are not considered servos.

* Currently AMC has limited or no product compatibility with this type of motor.

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To be as flexible as possible Advanced Motion Controls drives are compatible with many types of feedback.

In modern control systems, feedback devices are used to ensure that the motor or load reaches the commanded position or velocity. Servo drives and controllers use this feedback to determine how much current to deliver to the motor at any time, based on its present position and velocity versus where it needs to be. Feedback devices can be split into two major categories, absolute and relative (also known as incremental).

TTL Quadrature

Also called A-B Quadrature Encoders. Encoders are the most prevalent position feedback device in motion control. An encoder consists of a glass disk or strip, with lines scribed or painted on its surface and at least two optical sensors. The sensors are arranged such that, as each line passes through the pickup assembly, one sensor ‘sees’ the line before the other. The order in which the lines are sensed determines the direction of motion. The number of counts that pass determine the position. The speed at which the counts pass determine the velocity.

Sinusoidal 1Vpp

A sinusoidal encoder is very similar to a standard quadrature encoder. However, instead of providing two square waves 90° out of phase (from the A and B sensors) while the motor or load is moving, sinusoidal encoders provide two sine waves 90° out of phase (sine and cosine). When sent to subsequent electronics, these sine waves can be decoded in a manner similar to quadrature encoders. In addition, interpolation can be performed on these sine waves to increase positioning resolution. AMC drives can interpolate an additional 1024 counts between the sine waves.

Serial Interface

Some absolute feedback devices employ a serial interface as a means of transferring the position data. Because of the latency intrinsic to serial communication, the serial interface is usually only used to query the absolute position, and only while the motor is stationary. After the absolute position is known, an incremental device is used to track the changes in position thereafter. Two common serial interfaces are the Stegmann Hiperface® and the Heidenhain EnDAT® protocols.

Other Feedback

Hall Sensor

Hall sensors are the most basic and common feedback devices found on brushless motors. Hall sensors are favored because of their simplicity and because they can provide absolute position within one electrical cycle. This makes Hall sensors ideal for initial commutation on startup. However, Hall sensors have very low resolution which makes them inappropriate for fine positioning. Because of their low resolution, a drive typically uses an encoder in addition to the Hall sensors for fine velocity and position control. The Hall sensors act as the reference for initial commutation and the encoder provides more precise feedback.

Many encoders provide 'commutation tracks' or 'Hall tracks' which take the place of actual Hall sensors. For an encoder with commutation tracks simply wire the commutation lines into the Hall sensor inputs on the drive.

Resolver

A resolver is essentially a rotary transformer. Resolvers consist of three coils, usually placed at the end of a rotary brushless motor. The excitation coil is connected to the shaft of the motor, and is supplied with a sine wave of nominal frequency (e.g.: 5kHz). The other two coils are stationary, and are oriented perpendicular to each other. Each of the receiving coils act as secondaries, while the excitation coil acts as a primary. As the motor turns, the amplitude and polarity of the transferred excitation signal resulting in each of the receiving coils varies sinusoidally.

Resolvers provide absolute position within 1 revolution. AMC drives can interpolate resolver resolutions up to 16bit (over 65,000 counts per revolution)

Tachometer

A tachometer is a DC generator that connects to a motor to measure velocity directly. The DC output voltage of a tachometer is proportional to speed. This provides good analog feedback for velocity control, and is most often used to provide velocity feedback for analog servo amplifiers.

Potentiometer

Even a standard potentiometer (variable resistor) can be used as a feedback device. When coupled to mechanics that are only meant to turn a finite number of turns, a pot can be used for absolute position feedback.

LVDT

Linear Variable Differential Transformer. This feedback device outputs a voltage that is proportional to the position. To work with AMC drives a signal conditioner must be used to generate a voltage proportional to position.

RVDT

Rotational Variable Differential Transformer. This is a rotary version of the LVDT.

Your Custom Feedback Device

If you have a feedback device that is not listed here, please let us know! We may be able to design a product that fits your needs.

*Advanced Motion Controls makes drives that are compatible with all of the feedback listed above.

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A mode of operation is an indication of what the drive is controlling in a servo system. The three major modes are: Position, Velocity and Torque. The output of a servo system is usually position. Within the system however there are three possibilities of what loop(s) the drive is closing. The drive could be in torque mode and the controller could close the velocity and position loops. The drive could be in velocity mode and the controller could close the position loop. Or the drive could be in position mode.

The choice of what mode to run in is related to both the desired performance and what other components are available in the system.

This is the preferred mode in high precision, high bandwidth systems. This mode gives the most control of the motion to the controller where the controller must close the velocity and position loops.

In current mode the current output from the motor is proportional to the input reference signal. Motor output torque is proportional to the motor current. Torque mode is recommended if the servo amplifier is used with a digital position controller (under this condition, a movement of the motor shaft from the desired position causes a large correcting torque, or "stiffness"). A "run away" condition may occur if operated without a digital position controller.

These modes are considered to be 'pseudo velocity' because they do not use feedback devices to directly determine the velocity. Instead they use the motor terminal voltage to estimate velocity.

Open-Loop Mode

In this mode the input reference signal commands a proportional motor voltage (by changing the duty cycle of the output power stage). This mode is not a closed loop configuration (unlike the other modes described); therefore the average output voltage is also a function of the power-supply voltage.

Voltage Mode

In voltage mode, the input reference signal commands a proportional motor voltage regardless of power supply voltage variations. This mode is recommended for velocity control when velocity feedback is unavailable and load variances are small.

IR Compensation Mode

If in voltage mode if there is a load torque variation, the motor current will vary since torque is proportional to motor current. Hence, the motor terminal voltage will be reduced by the voltage drop over the motor winding resistance (IR), resulting in a speed reduction. Thus, motor speed - which is proportional to motor voltage (terminal voltage minus IR drop) - varies with the load torque.

In order to compensate for the internal motor voltage drop, a voltage proportional to motor current can be added to the output voltage. An internal resistor adjusts the amount of compensation. Use caution when adjusting the IR compensation level. If the feedback voltage is high enough to cause a rise in motor voltage with increased motor current, instability occurs. Such result is due to the fact that increased voltage increases motor speed and thus load current which, in turn, increases motor voltage. If a great deal of motor torque change is anticipated, it may be wise to consider the addition of a speed sensor to the motor (e.g. tachometer, encoder, etc.).

Tachometer Velocity Mode

The addition of a DC tachometer to the motor shaft produces a voltage proportional to speed. With this addition, the tachometer output voltage replaces the motor terminal voltage as the controlled variable. Since this voltage is proportional to the motor speed, this operating mode truly controls motor speed in a closed loop fashion.

Hall Velocity Mode

The frequency of Hall sensors is proportional to the motor speed. In most brushless amplifier series, an internal circuit decodes velocity information from the motor mounted Hall sensors. This analog signal is available for closed loop velocity control. This mode does not provide good velocity control at low speeds (below 300 rpm for a 6-pole motor, 450 rpm for a 4-pole motor, or 900 rpm for a 2-pole motor) since the resolution of Hall sensor signals is not very high.

Encoder Velocity Mode

The frequency of a motor mounted encoder is proportional to the motor speed. An internal circuit can decode velocity information from such encoder feedback. This analog signal is available for closed loop velocity control. Since the resolution of an encoder is much higher than of Hall Effect sensors, much better low speed regulation can be obtained.

Resolver Velocity Mode

Essentially this is very similar to encoder velocity mode since the drive converts the resolver feedback into emulated encoder counts.

Position Mode

The motor position is commanded by the drive. This mode allows the user to position the motor exactly where the application requires. The closed loop position control may use encoders, resolvers or even analog voltages as position feedback sources. These feedback devices will be proportional to the commanded motor position.

Encoder Following / Electronic Gearing

Encoder Following is a master / slave relationship where one motor follows the position of another through their respective encoder feedback signals. An example for the usage of encoder following is controlling the position of a motor with a separate encoder mounted on a hand-wheel without having them mechanically coupled. Electronic gearing allows the user to set the ratio between the two motors to be more than just 1:1.

A possible use of encoder following is for driving multiple motors that need to move as if they're coupled together. Another application can be a manual encoder-mounted hand-wheel control of

A possible application of encoder following is a manual control

… is a hand-control of a motor position through an encoder mounted hand-wheel without having them mechanically coupled.

It can also be used for driving

Step & Direction

This is the description for Step and Direction mode.

Analog Position Loop Mode

In this mode the feedback device is an analog potentiometer mechanically tied to the positioned object, thus providing position feedback. The wiper of the potentiometer is connected to one of the differential input terminals (-REF). The command is an analog signal, which is connected to the other differential input terminal. It is recommended to use a tachometer to close the velocity loop. The input reference gain can be increased for the analog position mode by ordering the -ANP extension. Example: 12A8X-ANP. The following figure is a typical wiring diagram of the analog position mode:

Figure 7 – Analog Position Loop Mode Example

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To increase versatility there are many ways to control AMC drives including analog signals, digital signals and network commands.

Analog commands associated with servos are most commonly DC voltages between -10V and +10V. Typically the negative range of voltages command motor movement in one direction, while the positive range of voltages command movement in the opposite direction.

To send analog commands to the drive, one can use a motion controller or PLC, or even turn a potentiometer by hand. An analog command sends a signal to the amplifier which results in a proportional output from the motor.

+/-10V

The range of signals is -10V to +10V. The output is proportional to the magnitude of the signal where 0V is zero output. Positive voltage cause positive output, and negative voltages cause negative output. Other variations can be 0-5V and 0-10V commands but these are less common.

Sinusoidal Signal

Some motion controllers can command torque and commutation information by sending two sine wave signals to the drive. One sine wave is offset from the other by 120 degrees. The amplitude of the signals control the motor torque while the timing of the sine waves control the commutation. AMC S-series drives are controlled in this manner.

4-20mA

4-20mA control is typically used in process applications. This type of control is not normally associated with servo control.

PWM & Direction

With PWM and Direction control, two digital lines are used.

The first line is a PWM signal that switches anywhere from 5kHz to 20kHz. Changing the duty cycle of the digital signal changes either the output duty cycle of the drive or the output current.

The second line is a direction signal. The output direction is controlled by holding this line high or low.

Step & Direction

Step & Direction control in AMC drives is intended to ease the transition from a stepper motor system to a servo system. This feature allows a user to retrofit their existing stepper system to a servo system and keep the same stepper controller.

In addition to step and direction in position mode we also have step and direction in velocity mode. Users may find this useful if precise velocity commands are needed since step and direction signals are relatively noise immune and precise.

Encoder Following

A drive in Encoder Following mode will monitor the movement of a motor and mirror the motion on a second motor. The drive uses the encoder output of the master as the command to the slave. AMC drives also have electronic gearing capability which allows them to not only follow motors in a 1:1 ratio but any ratio desired by the user, including 'gearing up' and 'gearing down'.

Indexing

Indexing drives use digital inputs to command the drive to move to pre-defined positions. Acceleration, deceleration and velocity are all set when the drive is configured. Currently AMC does not have an indexing drive.

In its simplest implementation a network can be used to configure a drive for operation. A more complex implementation could use the network to monitor the drive during operation and give uncoordinated motion commands. At the highest level, a network can be used to close the position and velocity loops in addition to all of the above and precisely coordinate motion between many axes.

Networked drives have many advantages including better system diagnostics, more precise commands and possibly reduced system cost if the controller can be eliminated. They also have some disadvantages including compatibility issues between component manufacturers, bandwidth limitations depending on the network chosen, the learning curve required to learn new network protocols and increased cost if more expensive drives must be used with the network.

Not all networks are the same so choosing the correct network for the application is paramount in designing a system that works.

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RS232 and RS485 are good for drive configuration, I/O monitoring and some motion commands. AMC RS232/485 drives use a proprietary communication protocol for drive configuration and diagnostics. It is possible to send motion commands to the drive but performance is limited since the protocol was not designed for this purpose.

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The CANopen protocol and hardware is designed for motion control. It uses the advantages of distributed control to reduce network traffic by allowing the drive to make many of the motion control calculations.

CANopen stands for Control Area Network Open protocol. It was designed for the control area network physical layer, and is governed by CAN in Automation (CiA), a non-profit users group. It provides a real-time, deterministic network solution, which is required for genuine distributed control architectures. The drive closes all necessary loops, allowing less demand from the controller. For more information on CANopen and distributed motion control, see the CANopen section under Digital Support. More information about CANopen can be found at http://www.can-cia.org, the web site of CiA. Another useful site is http://www.canopen.us, a web site for US users of CANopen

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SynqNet is a truly centralized network solution that is fast enough to simultaneously monitor the I/O on multiple axes, continuously monitor position velocity and torque, close the velocity loop and close the position loop. Advanced Motion Controls SynqNet™ drives are used in the most critical, high bandwidth and accurate applications.

SynqNet™ is a high performance motion control network, developed by Motion Engineering Inc. SynqNet™ is a 100Base-T based motion control network, which replaces the conventional +/- 10V and encoder interface between controller and amplifier with a high-speed digital interface. The drive closes the current loop and relays information to the SynqNet controller, which closes additional loops. The 100Base-T physical layer network is identical to the Ethernet physical layer, and is fully defined in the IEEE802.3 standard. The SynqNet protocol provides a real-time, deterministic communication mechanism between controller and drives.. More information on SynqNet™ can be found at www.synqnet.org and our SynqNet™ page.

USB

USB ports are integrated into every new computer which makes this type of connection attractive. As serial ports become replaced by USB ports, creating a USB compatible drive may become a necessity. Similar to the RS232 serial port however, the USB port will most likely only be used for set-up and configuration of the drive.

Ethernet

Ethernet is a widely used method of networking computers and is capable of communications up to 10,000,000 bits-per-second. Hardware such as Ethernet cards and cabling is readily available and inexpensive.

Unfortunately industry has had difficulty implementing Ethernet and taking advantage of its abilities. Ethernet has higher overhead than most protocols especially when the TCP/IP stack is added. As motion control axes are added to the system, Ethernet based networks begin to bog down to multiple milliseconds and longer - much too slow for the real-time requirements of a servo system.

New IEEE standards have been adopted that are designed for real-time systems. Advanced Motion Controls will consider Ethernet as a solution after it has been further developed and validated for motion control.

Advanced Motion Controls includes software to communicate with our drives. The main screen looks like a servo control loop which most engineers are familiar with. Navigating to the correct configuration screen is simplified since the links are located in the logical areas of the control loop.

Configuration software that allows a Windows based PC to communicate and configure a drive via serial port or SynqNet™. You can also use the software to upgrade your drive to the latest firmware release.

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Configuration software that allows a Windows based PC to communicate and configure an AMC drive over a CANopen network. You can also use the software to upgrade your drive to the latest firmware release.