EtherCAT Control I/O Solutions
What is EtherCAT?
EtherCAT (Ethernet for Control Automation Technology) is an Ethernet-based fieldbus system developed for industrial computer network protocols offering real-time distributed control, which is needed in industrial automation, motion control applications (robotics), real-time control (CNC, milling machines, safety systems, printing presses), and data acquisition systems (wind turbines, weighting systems). EtherCAT Device Protocol is based on master-slave communication between real-time controllers and field devices (I/Os, servodrives, sensors, actuators, …).
EtherCAT Automation Protocol (EAP): communication between controllers, or between controllers and MES/ERP systems, on standard factory networks.
Industrial 4.0 will create huge demands for integrating information technology (IT) and operational technology (OT). To bridge IT and OT, big data needs to be aggregated from the field. For this reason, EtherCAT has become the major protocol of choice for automation control because of its fast communication, flexible topology, and distributed architecture.
How it works?
EtherCAT works like this — the device accepts the packet, and as soon as it has received the header (and realized that this is an EtherCAT packet), it starts sending this packet further, in the process of sending, replacing the bits of the packet in which it should send information to the necessary ones. EtherCAT slave devices process data (extracting and inserting) "on the fly”. In the EtherCAT’s master & slave configuration, if the output of the last node is not allied to the master, then data is returned automatically in another direction through the EtherCAT protocol. So, timestamping is maintained.
As a result, the master can send a kilobyte packet with speeds for a hundred motors and empty spaces for a hundred sensors, each of the sensors will write its data into it, and each motor will read its own, the packet will return to the master, and all this will take approximately a microsecond. Where are 3 synchronization modes for slave devices:
- DC -Synchronous (SYNC interrupts)
- SM-Synchronous (sync to cyclic frames)
- Free run.
An EtherCAT master sends data by means of the MAC (Media Access Controller) at layer 2 (the data layer) in the standardized ethernet OSI model. No additional communication processors are needed, which means that EtherCAT master functionality can be implemented on any device that has an Ethernet port. The theoretical device limit for an EtherCAT network is 65,535 slaves.
EtherCAT does not use IP addresses. The order of network wiring defines each device, and single-panel machines can daisy-chain from device to device. EtherCAT Extenders support star and tree topologies, and dual EtherCAT ports support ring topologies. UDP: EtherCAT protocol can be transported in UDP datagrams. The assigned UDP port for EtherCAT is 0x88a4
Advantech offers a complete portfolio of EtherCAT Control I/O solutions that ensure easy data collection and processing for IoT applications.
In recent years, EtherCAT has become the main protocol for automation control due to its rapid communication cycles, flexible topology, and distributed architecture. Building on those advantages, Advantech’s EtherCAT master/slave modules combine hardware and software to enable time-dependent data collection and local aggregation. This accelerates data processing for integrating OT and IT in order to optimize performance and accelerate the realization of IoT-based smart factories. Advantech’s EtherCAT control I/O solutions integrate hardware and software foundations to offer a complete portfolio of EtherCAT MainDevice (MDevice) and SubordinateDevice (SubDevice) modules, supporting the integration of OT and IT for increased efficiency and performance.
1. Control Platform (Control IPC: AMAX-5000 series)
2. Subordinate Device Modules
2.1 Digital I/O and Position Measurement Modules (For example AMAX-5052 - 16-ch Digital Input EtherCAT Slice I/O)
2.2 Analogue I/O and Temperature Measurement Modules (For example AMAX-5017H - 4-ch High speed Analog Input EtherCAT Slice I/O)
2.3 EtherCAT Slice IO Extension Module (For example AMAX-5079)
2.4 Power Input Module for EtherCAT Slice IO (For example AMAX-500)
2.5 EtherCAT Coupler for AMAX-5000 Slice IO (For example AMAX-5074)
3. EtherCAT I/O MDevice Card (For example PCIE-1203IO - 2-port EtherCAT PCI Express Card)
4. 1-Port EtherCAT I/O MDevice Card (For example PCM-26R1EC 1-Port EtherCAT I/O MDevice mPCIe Card)
5. EtherCAT Gateways (For example EKI-1242IECMS Modbus RTU/TCP to EtherCAT Fieldbus Gateway, Wide Temperature)
6. EtherCAT SubDevice Modules
6.1 Digital I/O Modules (For example AMAX-485632-ch Isolated Digital Input and 32-ch Isolated Digital Output EtherCAT Remote I/O Module)
6.2 Analog I/O Modules (For example AMAX-48178-ch, 16-bit Isolated Analog Input EtherCAT Remote I/O Module)
6.3 EtherCAT Junction Modules (For example AMAX-4870 - 6-port EtherCAT Junction Module)
6.4 Motion Control Modules (For example AMAX-3285IO8-axis EtherCAT Motion SubDevice with 16DI/16DO Expansion)
Solution System Architecture
Why choose Advantech EtherCAT Control I/O Solutions?
Advantech EtherCAT hardware MDevice products adopt SoC (System-on-a-Chip) design to execute the EtherCAT protocols, guaranteeing real-time capabilities of the I/O access with the shortest cycle time up to 200 μs.
- Lower TCO (Total Cost of Ownership) for PC-based EtherCAT I/O Solution. The cost of implementation solution based on EtherCAT is usually smaller compared to both PROFINET IRT & SERCOS III.
- Diagnostic Tool for Communication Quality Checking. EtherCAT provides diagnostic information both at the hardware (link lost counters, invalid frame counters) and at the software level (state machine errors, Diagnosis history object).
- Easy for Wiring and Installation, SubDevice Modules Provide Different Form Factors
- EtherCAT Hardware MDevice to Guarantee Real-Time Performance. EtherCAT is literally faster than CANopen. EtherCAT is deterministic compared to Modbus.
This protocol provides high speed, less data traffic, less hardware cost, and more precision & synchronization mechanism of the clock as compared to Ethernet.
EtherCAT can serve as the transport protocol for some other protocols like BACnet, EtherNet/IP, PROFINET IO, or Modbus. Slave devices can support any TCP/IP application program like HTTP, HTTPS, or HTML.
EtherCAT devices Connectivity
EtherCAT is a full duplex system without external switches. Instead, each device embeds a switch. Each device has two RJ45 ports. For connecting EtherCAT devices Ethernet cable categories CAT5, 6, and 7 according to EN 50173 or ISO/IEC 11801 should be used. Inexpensive Industrial Ethernet cables can be used between two nodes up to 100 m apart in 100BASE-TX mode.
Fiber optics (such as 100BASE-FX) are also feasible to utilize for distances up to 2 kilometres to enhance speed & include galvanic isolation in between devices.
This makes line topology possible. EtherCAT Extenders support star and tree topologies, and dual EtherCAT ports support ring topologies. Line, bus, tree, star or daisy-chain: EtherCAT supports almost all topologies.
Compatibility by Type 12 IEC 61158 standard
The EtherCAT protocol is described in the International Electrotechnical Commission's IEC 61158 standard and covers digital data communications for measurement and control. It specifies hard and soft real-time computing requirements in automation technology.
During the time IEC 61158 standard the specifications have been updated, but improvements only extended compatibility. This means that current devices can be used in existing systems without any problems and without having to consider different versions. The extensions include Safety over EtherCAT for machine and personnel safety in the same network, and EtherCAT P for communication and supply voltage (2 x 24 V) on the same 4-wire cable.
EtherCAT G and EtherCAT G10 are new versions of the EtherCAT protocol operating at 1 Gbit/s and 10 Gbit/s, respectively. EtherCAT G and G10 are fully compatible with the original EtherCAT. Devices that were designed for the original 100 Mbit/s EtherCAT can be seamlessly integrated into an EtherCAT G and G10 system. Likewise, EtherCAT G slaves can operate on an EtherCAT master (as long as the master has a Gbit/s port), although EtherCAT G and G10 devices will behave like 100 Mbit/s EtherCAT devices when they’re used in an EtherCAT system — that is unless the new branch concept is used.
EtherCAT Redundancy due to time-stamped data
EtherCAT protocol uses the time stamp. Each node adds a timestamp when it receives a packet, and then stamps it again when it sends it on to the next node. So when the master receives back the data from the nodes, it can easily determine the latency of each node. Every data transmission from the master gets an I/O time stamp from every node. In the EtherCAT’s master & slave configuration, if the output of the last node is not allied to the master, then data is returned automatically in another direction through the EtherCAT protocol. So, timestamping is maintained.