JARGON

Back EMF:

The electromotive force (voltage) produced by a motor acting as generator. Back EMF is generated at all times by a motor although it will be smaller than the voltage being used to drive current though a motor when running at constant speed.

Backlash:

The motion required to take up the mechanical tolerances or wear after change of direction in a machine part such as a gearbox.

Brushless Motors:

Motors in which commutation is performed using electronic switches rather than using mechanical brushes. In most DC Brushless Motors the armature supports permanent magnets and the motor coils are arranged mounted surrounding the armature. This configuration reverses that of a conventional DC brushed motor.

Cam Profiles:

CAMs allow users freedom to create their own motion profile dedicated to the application requirements. All Motion Coordinators have very powerful and flexible CAM commands which make possible applications that can be impossible to construct without these facilities.

Motion Coordinators have a memory TABLE in which CAM profile shapes may be constructed. The size of the TABLE varies between 16000 points and 250,000 points. The CAM profile shapes can be constructed offline, or built by the Motion Coordinator itself, or imported from programs such as Excel. Trio provides a very useful CAMGEN utility for helping with the construction of CAM profile shapes.

Motion Coordinators provide two fundamental types of motion command for using the CAM profile shapes. These allow a CAM to be executed over a flexible timebase or as motion linked to another machine motion. The CAM shapes can be used in a very flexible way, for example they can be stretched as they are used, and the controller can choose to use just a portion of a larger shape. There are controls too to allow flexible repeating of CAM shapes.

These controls allow profiles to be executed backwards and forwards to allow the Motion Coordinator to simulate mechanisms which can be run in either direction. There are also controls to allow the starting of CAM’s on a registration event or when a machine position is reached. For complex applications, multiple CAM shapes can be merged together in a seamless way.

CANOpen Interface:

CANopen is an internationally standardized higher-layer protocol for embedded control system running on CANbus. CANopen networks are used in a broad range of application fields such as machine control, medical devices, off-road and rail vehicles, maritime electronics, building automation as well as power generation.

Trio has a long history using CANopen for drive and I/O control. All Trio controllers have a built-in CANbus port for system I/O expansion to our modules. Trio has also in the past used CANopen for deterministic control or servo axes, however, faster and higher bandwidth networks such as EtherCAT have taken the lead. TrioBASIC provides commands for interfacing to many third party CANopen devices including remote I/O systems, pneumatic valve stacks, and high level messaging to servo drives.

Commutation:

The process whereby current is fed to the different coils of a motor to try to maintain constant torque as the motor rotates. In a brushed DC motor the brushes act as on/off commutation switches. In a brushless motor the servo drive gradually varies the current into each phase of the motor.

Communication Interfaces:

Ethernet

Trio's Ethernet daughter board enables local or remote access using the popular 10-baseT standard. Connection is via a standard RJ45 connector on the front of the daughter board which has connection and activity LEDs to aid commissioning. Ethernet’s standard features allow speedy connection to a factory network, office network or even the internet. An Ethernet connection to the Motion Coordinator gives access to the command line via a Telnet/TCP connection, allows Motion Perfect to be connected remotely, enables a remote PC to run motion programs using the TrioPC ActiveX component and provides a high speed link to a device like an HMI running Modbus TCP.

Modbus

Every Motion Coordinator now has the Modbus RTU protocol available as standard on at least one serial port. Modbus provides single point to point communication between a programmable keypad/display and the Motion Coordinator. The keypad has access to all the internal global variables within the Motion Coordinator and numbers can be transferred in or out using 16 bit, 32 bit or IEEE floating point formats. As the keypad is the bus master, it can access one Motion Coordinator over RS232 or multiple Motion Coordinators using RS422/RS485. Baud rate and slave address are set in the TrioBASIC program during serial port initialisation.

DeviceNet

As a standard option, the built-in CAN port works as a slave device on the DeviceNet network. The Motion Coordinator supports Explicit Messages of the predefined master/slave connection set and Polled I/O, which allows the DeviceNet master to send 4 integer variables to and to read 16 integer variables from the Motion Coordinator. These values are mapped directly to global variables in the Motion Coordinator and in addition the explicit messaging can be used to read or write any global or table data value.

USB

USB allows convenient connection to a PC for use with Motion Perfect or a Windows application via the TrioPC OCX control. For improved noise immunity, Trio can supply a filtered 1.5m long USB cable, part number P361.

CANopen

Motion Coordinator range has integrated support for DS301, DSP401, CanOpen I/O Modules and DSP402, CANopen Servodrive protocol. Motion Perfect has a setup wizard for compatible CANopen DSP402 drives and support for 3rd party CANopen I/O modules. Please contact Trio for a list of DSP401/DSP402 compatible 3rd party hardware.

Profibus

Data transfer between the Profibus master and the Motion Coordinator uses cyclic data transfer which can handle up to 16 signed words in and 16 signed words out of the global memory area. Cable and connections are straight-forward due to the 2 wire RS485 technology that Profibus uses at the physical layer. Auto baud rate detection is supported up to 12Mbaud and the Profibus master is set up using the GSD file provided by Trio.

Continuous Motion:

Motion Coordinators are designed from the ground up to support motion applications with continuous motion in one direction. In such applications as printing, and flow wrapping the machine is required to remain under precise position control whilst acting in some ways as just a speed axis.

The Motion Coordinator allows for endless motion axes which will “wrap” their axis positions either automatically or at a time to suit the application program. This shifting of the frame of reference of the axis can occur during moves and at full speed. “Virtual” axes can be defined in a Motion Coordinator.

A virtual axis is an axis that is provided for the convienience of the programmer. They may be used for example to superimpose an advance or retard move on to a continuous motion in a very simple way.

Coordinate Transform:

Coordinate transformations allow a machine to be programmed in a “Frame” which does not correspond one-to-one with the machine axes. An example of a very simple coordinate transform is given in the diagram. In this class of “single belt” machine, two stationary motors are used to produce X-Y motion. However if the motion required is in the Y direction both motors must move in opposite directions. For motion in the X direction the motors must move in the same direction. Frame transformations are commonly used with “robots” but can be useful in a much wider variety of machine types.

 

Datum:

The Datum command is the homing function in Trio

Electronic Commutation:

Commutation in a brushless motor system. The servo drive switches current into the motor windings depending on the relative position of the rotor and the motor windings.

Encoder:

Usually refers to an Incremental Optical Encoder. An encoder may be mounted on a motor or machine part to indicate it’s position to a control system. An incremental optical encoder consists of a disk with a few hundred or thousand slots, and 2 optical sensors which produce an out of phase pair of signals referred to as A and B channels. A third optical sensor, produces a once per turn signal, referred to as the Z, or 0, channel. Incremental Optical Encoders provide a control system with incremental position changes

EnDat™:

A format devised by Heidenhain for serially transmitting information from an absolute encoder into a control system. RS485 signals are used to transmit the absolute encoder position (including possibly multi-turn data) at high speed into the control system. EnDat is the trademark of Heidenhain.

EtherCAT:

High Speed network based on Ethernet HW for coordinating motion and I/O. This is an open standard widely being adapted by most all manufactures.

Trio's EtherCAT interface is a fully deterministic control interface based on standard 100base-T Ethernet hardware to servo drives and I/O devices. It can support up to 64 motion axes. EtherCAT replaces the traditional 10V analogue servo command and encoder feedback, or step/direction command signals to the drive electronics. The network was designed from the outset for real time motion and automation control and Trio support full cyclic, synchronous operation on all axes.

With EtherCAT, the Ethernet packet or frame is no longer received, then interpreted and copied as process data at every node. Rather, the EtherCAT slave devices read only the data addressed to them while the telegram passes through the device with negligible latency. Similarly, input/output data are inserted while the telegram passes through the slave. Advantages of EtherCAT include high-speed motion control, high update rates coupled with larger amounts of data transfer, reading and writing drive parameters and I/O and low installation cost using shielded Cat5 Ethernet cables.

CANopen over EtherCAT, also known as CoE, is the main protocol supported by the Motion Coordinators. Other protocols are supported for use with IO and some servodrives require a different protocol but they are in the minority.

Feedback:

The provision of measured information from a system under control to allow a servo loop to be constructed. A servo motion control system typically will have current, speed and position feedback.

Flying Shear:

Motion Coordinators provide functions to make applications such as synchronised flying shears easy to implement. The conveyor being synchronised to need not be under control of the Motion Coordinator. There are 3 types of "linked" moves available.

Flying shears are typically implemented with a pair of MOVELINK commands. The MOVELINK gives the position synchronisation required and can be programmed to start very accurately relative to a position on the conveyor.

 

Gearbox; Electronic :

Electronic gearboxes allow a Motion Coordinator to simulate the motion that might be mechanically performed using a gearbox. Electronic gearboxes are the simplest type of “linked motion” that Trio Motion Coordinators can execute. With “linked motion” a motor axis is program linked to the measured position of another axis rather than using a timebase. Constructing gearboxes electronically is easy and offers great flexibility to machine builders.

Gray Code:

A format for encoding numbers used instead of binary in absolute encoders. Gray codes allow only one bit of the pattern to change at a time when counting up or down. For example, when changing from 15 to 16 in binary bits 0,1,2 and 3 will all change simultaneously.

Hall Sensors:

A simple low cost way of providing a brushless motor’s approximate absolute position to a servo drive. Hall sensors are often used to allow for simple trapezoidal commutation.

Hiperface:

A format devised by Stegmann for serially transmitting information from an absolute encoder into a control system. RS485 signals are used to transmit the absolute encoder position (including possibly multi-turn data) into the control system. Hiperface is the trademark of Max Stegmann GmbH.

Hydraulic Interface:

Being an industry standard command signal, the +/-10V output from Trio can also command other devices such as pneumatic and hydraulic servo valves. These devices while under closed loop PID control offer very good performance of air and hydraulic controlled loads.

Position feedback can be incremental or absolute encoders, or analogue voltage. A servo axis in the Trio controller can be tuned to control such valves. Alternatively, for control of low bandwidth servo actuators, PID loops can be written at the application level for more flexibility.

Inertia:

The resistance of a body to accelerate when a force is applied due to its mass.

Interfaces:

CANopen

CANopen is an internationally standardized higher-layer protocol for embedded control system running on CANbus. CANopen networks are used in a broad range of application fields such as machine control, medical devices, off-road and rail vehicles, maritime electronics, building automation as well as power generation.

Trio has a long history using CANopen for drive and I/O control. All Trio controllers have a built-in CANbus port for system I/O expansion to our modules. Trio has also in the past used CANopen for deterministic control or servo axes, however, faster and higher bandwidth networks such as EtherCAT have taken the lead. TrioBASIC provides commands for interfacing to many third party CANopen devices including remote I/O systems, pneumatic valve stacks, and high level messaging to servo drives.

EtherCAT

Trio's EtherCAT interface is a fully deterministic control interface based on standard 100base-T Ethernet hardware to servo drives and I/O devices. It can support up to 64 motion axes. EtherCAT replaces the traditional 10V analogue servo command and encoder feedback, or step/direction command signals to the drive electronics. The network was designed from the outset for real time motion and automation control and Trio support full cyclic, synchronous operation on all axes.

With EtherCAT, the Ethernet packet or frame is no longer received, then interpreted and copied as process data at every node. Rather, the EtherCAT slave devices read only the data addressed to them while the telegram passes through the device with negligible latency. Similarly, input/output data are inserted while the telegram passes through the slave. Advantages of EtherCAT include high-speed motion control, high update rates coupled with larger amounts of data transfer, reading and writing drive parameters and I/O and low installation cost using shielded Cat5 Ethernet cables.

CANopen over EtherCAT, also known as CoE, is the main protocol supported by the Motion Coordinators. Other protocols are supported for use with IO and some servodrives require a different protocol but they are in the minority.

Hydraulic

Being an industry standard command signal, the +/-10V output from Trio can also command other devices such as pneumatic and hydraulic servo valves. These devices while under closed loop PID control offer very good performance of air and hydraulic controlled loads.

Position feedback can be incremental or absolute encoders, or analogue voltage. A servo axis in the Trio controller can be tuned to control such valves. Alternatively, for control of low bandwidth servo actuators, PID loops can be written at the application level for more flexibility.

Panasonic RTEX

Ethernet-based control networks have prevailed as the technology of choice for motion controller to servo drive interfacing. RTEX (Realtime Express) is Panasonic’s propriety Ethernet network. It is deterministic running at 100Base-T and is designed specifically for real time motion and IO control.

Trio has an interface module for the MC464 Motion Coordinator to connect Panasonic RTEX drives. Advantages of RTEX are fast startup and close integration of service channel support tools.

Piezo

A piezoelectric motor or piezo motor is a type of motor based upon the change in shape of a piezoelectric material when an electric field is applied to produce rotary or linear motion. Trio can use the 10V analogue command signal to control a piezo motor. These motors have unique control characteristics requiring specific features to accommodate. Trio has implemented parameters, such as output dead-band and offset, to allow control of piezo motors.

Sercos

Sercos is a high speed interface between the Motion Coordinator and one or more digital servo drives via fibre-optic link. The digital link allows the master to configure all the drive parameters, set the drives into run mode and close the position loop in real-time with a cycle period down to 250usecs.

The Sercos interface provides the flexibility of configuring multi-vendor control systems with plug and play interoperability. System designers are not limited to products from one manufacturer, but are free to choose those most suitable to solve their individual motion problems. The Sercos interface also reduces system cost, eliminates many types of noise problems and helps machine designers get motion control systems up and running quickly.

Servo

The traditional ±10V analogue command signal is a very well known and common interface to servo drives and many other control devices. Trio controllers generate a 10V signal with either 12-bit or 16-bit resolution that represents velocity or torque command to a servo drive.

Position feedback is typically used, and some drives have a simulated encoder output to feedback to the Trio to close the loop. Trio’s proven 5 term position loop controller software updates the analogue output at the programmed servo period. (Settable between 125 usec and 2 msec update rate) With Trio, the 10V command output can be user controlled in an open loop fashion. Directly setting the voltage output can be used for a variety of control options such as a speed reference to vector and variable frequency drives.

SLM

This special axis module provides a fully digital link to Control Techniques servo drives using the Control Techniques “Speed Loop Motor” SLM technology which gives a unique increase in servo loop performance over conventional analogue control loops.

Integrated support within Motion Perfect also allows for remote configuration of the drives and centralised distribution of drive parameters which gives fast maintenance turn-around in the event of a drive failure. The latest firmware supports “Position Loop Motor” PLM control which enhances the control loop accuracy and performance still further

Stepper

The stepper motor interface is most recognized for its simplicity and ease of use. The typical stepper output signal from a Trio controller is a differential (5Vdc line driver) Step and Direction signal. Open collector (single-ended) is used on some legacy products but is limited in high speed performance and robustness in terms of noise immunity.

The Trio connection to the stepper motor-driver is ‘open loop’, although encoder position verification is common. All 4 Series controllers use the RS422 differential line driver interface.

Interpolation: Linear / Circular:

Interpolation is the process where multiple axes work together to move an end point along a path defined in more than one axis. When performing interpolation, the Motion Coordinator calculates the “path speed” and works at the programmed speed along the interpolated path using Pythagoras’s theorum. Groups of axes cooperate in a “group” working with the velocity profile from a single axis known as the “base” axis of the group

 

 

 

Linear Motors:

Different configurations of linear motors are available which correspond with brushed, brushless servo or stepper motors. In many cases they can be considered as a rotary motor which has been rolled out flat. In a brushless motor typically permanent or electro magnets are arranged in a row and the electric windings are arranged on a moving carriage.

Load Inertia Ratio:

The ratio between the rotary inertia of the load as seen by an electric motor and the motors own inherent rotary inertia. As this ratio increases the load will become harder for the motor to control and the frequency response will become lower. A key factor in machinery design for servo systems is selecting the transmission ratio (using gearboxes and toothed belts) to achive a suitable balance between the Inertia Ratio and the motor speeds.

Microstepping:

A technique for sub-dividing steps on a stepper motor. Microstepping allows a stepping motor to stop and hold a position between the step positions, and reduces the jerk between steps giving less noise and resonance.

 

Optical Encoder:

See encoder.

Panasonic RTEX Interface

Ethernet-based control networks have prevailed as the technology of choice for motion controller to servo drive interfacing. RTEX (Realtime Express) is Panasonic’s propriety Ethernet network. It is deterministic running at 100Base-T and is designed specifically for real time motion and IO control.

Phase:

Many brushless motors are 3 phase. There are 3 coils within the motor which are each fed with a current depending on the position of the rotor. The relative current in each phase of the motor is calculated by the drive to produce the torque in the motor as it rotates.

Piezo:

A piezoelectric motor or piezo motor is a type of motor based upon the change in shape of a piezoelectric material when an electric field is applied to produce rotary or linear motion. Trio can use the 10V analogue command signal to control a piezo motor. These motors have unique control characteristics requiring specific features to accommodate. Trio has implemented parameters, such as output dead-band and offset, to allow control of piezo motors.

Process:

A process is a specific instance of a program. While it is possible to run the same program on separate processes, this is not generally necessary or desirable for automation projects. Term will be used interchangeably with program.

Program:

A group of code contained within a single file within a project. Large projects generally have many programs and often logical functions of the machine are separated into their own programs, such as Web Control and Labeller. Term will be used interchangeably with process.

PWM:

Pulse Width Modulation is the technique where current is fed into motor phases as a sequence of rapid on/off cycles using electronic switches such as transistors or IGBT’s at typically 20-50kHz. The short pulses are smoothed by the inductance of the motor windings.

 

Resolver:

A single turn absolute position feedback device frequently built into servo motors. The absolute nature of a resolver allows it to be used for electronic commutation. A resolver is a rugged inductive device that may be considered as signal transformer with a primary and 2 secondary coils. An excitation sin wave is fed into the primary and the rotary position of the transformer is indicated by the relative magnitude of the 2 secondary sin wave outputs.

Rotary Inertia:

The resistance of a rotating object to angular accelerate when a torque is applied.

Servo:

A servo system is a closed loop control system. It incorporates a demand requirement of a parameter such as position, feedback of the measured parameter, and a method to close the difference. A servo motion control system typically will have current, speed and position feedback servo loops.

Sinusoidal Commutation:

In an idealised system for controlling 3 phase motors the current in each phase will be varied in a sin wave profile as the motor rotates. Servo drives with accurate feedback of the motor position are able to modify the motor phase currents in this way using sinusoidal commutation. Sinusoidal commutation is typically performed in motors fitted with resolvers or absolute encoders.

SINCOS Encoder:

A type of optical encoder where the output signals are 2 analogue channels, out of phase by 90 deg. Electronic circuits can interpolate the analogue signals to give high position resolutions. A SINCOS encoder might have 4096 analogue pulses/turn. Each analogue pulse might be interpolated to 1024 sub-divisions giving a resolution of approximately 4 million counts/turn.

SLM:

This special axis module provides a fully digital link to Control Techniques servo drives using the Control Techniques “Speed Loop Motor” SLM technology which gives a unique increase in servo loop performance over conventional analogue control loops.

Integrated support within Motion Perfect also allows for remote configuration of the drives and centralised distribution of drive parameters which gives fast maintenance turn-around in the event of a drive failure. The latest firmware supports “Position Loop Motor” PLM control which enhances the control loop accuracy and performance still further

SSI:

A format for serially transmitting information from an absolute encoder into a control system. RS485/422 signals are used to transmit the absolute encoder position (including possibly multi-turn data) at high speed into the control system in either binary or gray code format.

Stepper Motor:

A type of electric motor typically used in lower cost applications. Current is applied to the motor phase windings either in steps or using “microstepping”, similar to sinusoidal commutation, to rotate a permanent magnet rotor synchronously. A stepper motor will maintain it’s position provided the torque and speed required by the application are well within the motor’s limits.

Stepper Interface:

The stepper motor interface is most recognized for its simplicity and ease of use. The typical stepper output signal from a Trio controller is a differential (5Vdc line driver) Step and Direction signal. Open collector (single-ended) is used on some legacy products but is limited in high speed performance and robustness in terms of noise immunity.

The Trio connection to the stepper motor-driver is ‘open loop’, although encoder position verification is common. All 4 Series controllers use the RS422 differential line driver interface.

Servo Interface:

The traditional ±10V analogue command signal is a very well known and common interface to servo drives and many other control devices. Trio controllers generate a 10V signal with either 12-bit or 16-bit resolution that represents velocity or torque command to a servo drive.

Position feedback is typically used, and some drives have a simulated encoder output to feedback to the Trio to close the loop. Trio’s proven 5 term position loop controller software updates the analogue output at the programmed servo period. (Settable between 125 usec and 2 msec update rate) With Trio, the 10V command output can be user controlled in an open loop fashion. Directly setting the voltage output can be used for a variety of control options such as a speed reference to vector and variable frequency

Synchronisation:

Synchronisation can mean many things in motion control. From coordinated movement of two or more axes in position lock, to triggered motion from an external event, to linking an axis to a reference in applications such as flying shears, winders and conveyor synchronisation.

A common requirement is to synchronise motion by triggering from an external event or position. In applications such as the labelling machine illustrated, how the Motion Coordinator handles synchronisation is critical to the performance of the machine.

 

Torque:

Turning, or rotational, force.

Torque Constant Kt:

How much torque a motor will produce per ampere of current supplied . One of the key parameters for a servo motor. The units are Newton Metres/Amp.

Trapeziodal Commutation:

A simple form of electronic commutation used where a brushless motor’s absolute position is returned by 3 on/off sensors built into the motor. This results in greater torque ripple in the motor output.

Trap Drive:

A low cost drive using trapezoidal commutation.

 

Voltage Constant Ke:

How much rotary speed a motor will produce for the voltage supplied . One of the key parameters for a servo motor.

WatchDog:

The WDOG Command is the enable command in Trio.