Modular EtherCAT Concept
Introduction
A modular approach to machine
The complete assembly of all connected parts or devices, of which at least one is movable. design has many benefits, including flexibility, scalability, and improved efficiency.
- Modular machines are split into sub-sections.
- Each sub-section containing all the mechanical and electrical devices, motors An actuator focused to a movement, converting electrical energy in a force or torque., sensors A type of transducer that converts one type of energy into another for various purposes including measurement or information transfer., etc. as well as corresponding application code, to work together to provide a functional A function calculates a result according to the current value of its inputs.
A function has no internal data and is not linked to declared instances. segment in the manufacturing workflow.
- The advantages to modular design are realized when the modules can be re-used.
- Examples include multiple module instances in the same machine and modules replicated across multiple machines.
Special consideration should be given to the physical layout, EtherCAT Ethernet ofr Control Automation Technology.
EtherCAT® is an open, high-performance Ethernet-based fieldbus system.
The development goal of EtherCAT is to apply Ethernet to automation applications which require short data update times (also called cycle times) with low communication jitter (for synchronization purposes) and low hardware costs. network topology, and the application code architecture to design a modular machine.
Modular machines are well suited to distributed EtherCAT device topologies (e.g., AKD-x-C/N drives In electrical engineering, a drive is an electronic device to provide power to a motor or servo.
Control device for regulating the speed, torque and position of a motor.
A unit controlling a motor using the current and timing in its coils.) but can also be applied to other EtherCAT devices.
Examples of Modular Machine Design Uses
Machine with Multiple Variants
- Machine Variant = Base module + one, two, (or more) additional modules.
- Base Module - Each machine variant has the same base set of EtherCAT devices.
- Additional Modules - Each module contains one (or more) EtherCAT devices.
Module Maintenance
- One (or more) modules are removed during machine operation.
- The machine continues to operate with the remaining base + modules.
Share Modules across Machines in a Factory Line
- Remove a module from machine A.
- Continue to operate machine A with the remaining base + modules.
- Move the module to machine B.
Modular Design Guidelines
These sections provide guidelines for modular design:
Single project file (.kas) with maximum EtherCAT topology
- Start with the full topology of EtherCAT devices planned for the maximum machine configuration.
- Perform an EtherCAT scan to discover the full set of EtherCAT devices and save the project file.
The PLC Programmable Logic Controller - A digital computer used for automation of industrial processes, such as control of machinery on factory assembly lines.
Used to synchronize the flow of inputs from (physical) sensors and events with the flow of outputs to actuators and events. code in the KAS Kollmorgen Automation Suite project can be adapted to handle the cases where modules containing EtherCAT devices are disconnected and removed for different machine configurations, maintenance, etc.
PLCopen/Pipe Network Axis to drive map is the same for all machine variants
Map the axes to the drives for the maximum EtherCAT topology.
The axis to drive map remains consistent if drives are disconnected/removed.
Whether drives are disconnected and removed from the end or from the middle of an EtherCAT network, the axis to drive map relationship remain the same.
Axis is simulated for a disconnected drive
The PLC application code must be adapt to the disconnected/removed devices.
Because disconnected drives behave as simulated axes/drives, the application code can perform many normal axis operations without code adaptations.
This provides flexibility for how the application code is designed to handle disconnected/removed drives.
Safety devices should not be disconnected/removed
FSoE Masters may not support modular EtherCAT designs.
If a safety device is disconnected and removed, the FSoE master does not allow normal machine operation.
See ECATDeviceAction about how to add the ability to connect/disconnect an EtherCAT device to the program The act of performing a sequence of instructions or commands..
Backing up Modular EtherCAT Devices
This procedure should be followed to backup EtherCAT devices when the modular EtherCAT feature is used to remove devices to create a machine variant.
See Modular EtherCAT Concept for more information.
- Run the KAS application which sets up the correct EtherCAT topology for the machine variant.
- Stop the KAS application.
- Do not power cycle or reboot the controller between Steps 2 and 3.
- Backup the EtherCAT devices.
See Backup Procedure for more information.
Limitations
- The device topology order cannot be rearranged.
- The Modular EtherCAT features are not supported with imported ENI files.
What happens when the device providing feedback to the digitizing axis is removed?
The feedback position Position means a point in space which is described by different coordinates.
Depending on the used system and transformation it can consist of a maximum of six dimensions (coordinates).This means three Cartesian coordinates in space and coordinates for the orientation.
In ACS there can be even more than six coordinates.
If the same position is described in different coordinate systems the values of the coordinates are different. becomes zero if the device providing the Feedback Position for the Digitizing axis is removed using the ECATDeviceAction function block A function block groups an algorithm and a set of private data.
It has inputs and outputs..
The feedback position data coming from the device is automatically connected to the digitizing axis when the device is reconnected to the EtherCAT network.
The Restore function only supports exact matches in the topology of backedup EtherCAT devices.
The Restore function only supports conditions where the network topology exactly matches the topology of the EtherCAT devices backup.
- There are a number of possible permutations and combinations when the Modular EtherCAT feature is used to create a machine with multiple variants.
- If a machine has a base EtherCAT module and a varying number of optional EtherCAT modules, then it is recommended that multiple backups are created:
- A base EtherCAT module backup and an optional EtherCAT module backup.
Example
This image shows a base EtherCAT module and a varying number of optional type A modules and type B modules.
We recommend that EtherCAT Devices backups be made with the following configurations in order to meet different scenarios.
- Backup #1: Base EtherCAT Module + one of Optional Module Modules built into the drive, with integrated position control, that provide special versions of the interface for the connection to the higher-level control. Type A.
- Backup #2: Base EtherCAT Module + one of Optional Module Type B.
With the two EtherCAT Devices backups, you may be able to restore various combinations by removing the other Optional Modules, keeping only the module you need to restore.
