Decentralised, end-to-end system synchronisation: With Distributed Clocks and EtherCAT.


EtherCAT | Distributed Clocks: Functional principle, application and diagnostics

Distributed Clocks are an essential element of EtherCAT communication enabling decentralised, end-to-end system synchronisation including CPU, I/O and drive technology components. In this 30-minute webinar, Martin Podrouschek and Fabian Assion, both Product Management I/O, will explain the functional principle of EtherCAT Distributed Clocks and the application with Beckhoff EtherCAT products. Moreover, the possibilities for parameter setting and diagnostics of Distributed Clocks in TwinCAT are outlined.

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TwinCAT 3

The TwinCAT software system turns almost any PC-based system into a real-time control with multiple PLC, NC, CNC and/or robotics runtime systems.


Beckhoff liefert ein umfangreiches Programm an Feldbuskomponenten für alle gängigen I/Os und Feldbussysteme.


The 8-channel digital input terminal EL1258-0010 acquires fast binary control signals from the process level and transmits them, in an electrically isolated form, to the controller. The EL1258-0010 is the ground switching version of the EL1258 and offers not only a higher channel density compared to the EL1252, but also higher performance due to the multi-timestamp function. Whereas the EL1252 can accept one edge change with timestamp per bus cycle, the EL1258-0010 offers the possibility to register up to 32 events with timestamps. The reduced timestamp width of 32 bits, which is equivalent to a resolution of 4.29 seconds, does not represent a functional limitation for most applications. The EL1258-0010 is synchronized with other EtherCAT devices through the distributed clocks system, so that events in the whole system can be measured with a uniform timebase.


The EL2521-xxxx output terminals change the frequency of a binary signal and output it (electrically isolated from the K-bus). The frequency is preset by a 16 bit value from the automation device. The signal state of the EtherCAT Terminal is indicated by light emitting diodes. The LEDs are clocked with the outputs and each displays an active output.


The EP7402-0167 EtherCAT Box offers two outputs with integrated controller for the direct connection of 24 V DC conveyor roller motors or other BLDC motors with max. 3.5 A. Eight additional digital inputs/outputs enable connection of e.g. photoelectric switches and communication between the box modules in operation without PLC. The EP7402-0167 takes over the complete control of a roller motor independently of the manufacturer of conveyor or motor. The connection is made directly to the three phases of the motor. Maximum rated current, acceleration or deceleration ramps and various other parameters can be configured and allow for a wide range of adaptations to different applications. The control of the motors is sensorless. The EtherCAT Box with IP 67 protection rating measures only 174 mm x 60 mm x 36.5 mm and can be easily mounted in standard C-channel or L-brackets on the conveyor frame. It requires no additional protective covering. Power supply and EtherCAT communication are realized via a B23 ENP connector with a current carrying capacity of 28 A/45 °C. In conveyor operation the EP7402-0167 can also be operated without PLC and provides functions such as ZPA (Zero Pressure Accumulation), single or block discharge.