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• Power delivery with the PoDL standard, which uses a DC voltage superimposed on data lines to supply power to devices connected to the network. This type of coupling can be achieved by only using passive components, and once the voltage on the receiver end is fi ltered, it can be directly used to power the device or a DC-to-DC converter, without requiring rectifi cation. By correctly dimensioning components in this type of coupling, a high-effi ciency system can be achieved. In this project, using standard components installed on the evaluation boards leads to an overall effi ciency of about 93% (with a 24V supply and total load current of 200mA). However, this result can be improved upon – indeed, most of the losses are due to resistive drops of the passive components along the power path. • Versatility, as it can be used for both last- mile and end-point connectivity. Analog Devices 10BASE-T1L parts have been tested for distances to 1.7km. They can also be daisy-chained with a low impact on system complexity. For example, by using the ADIN2111 two-port low complexity switch, it is possible to design devices that integrate daisy-chaining, making the link also suitable for end-point nets. • Easy to interface with existing equipment that already integrates an Ethernet controller, including personal computers and laptops. Data frames follow the Ethernet data-link standard, and all Ethernet-compatible protocols can be implemented over it, so only a media converter is needed as a bridge with standard Ethernet links. For example, the board used in this project, the EVAL- ADIN1100, can be used as a reference design for a transparent media converter, requiring only two Ethernet PHYs and an optional microcontroller for confi guration and debugging.
• High data rate, up to 10Mbps, full duplex. This, combined with the daisy- chain topology on which industrial Ethernet-based protocols can be implemented, allows it to be used in a real-time application, where deterministic transmission latency is required. • Isolation between the transceiver and media can be achieved with both capacitive or magnetic coupling, depending on the safety and robustness requirements of the application. Multiple measurements were done on the system to evaluate its performance. All the peripherals used to communicate with the ADIN1110 transceiver, and TMC5160
14 November 2023 | Automation
Figure 3: Firmware flowchart
controllers were confi gured for the maximum possible speed that is reachable with the standard hardware confi guration. Considering the 80MHz system clock of the microcontroller, the data rate of SPI peripherals was set to 2.5MHz for the motion controllers and to 20MHz for the ADIN1110 transceiver. For the TMC5160, by tuning the microcontroller clock confi guration and supplying an external clock signal to the IC, SPI frequency can be further increased to 8MHz, whereas for the ADIN1110 the maximum limit by data sheet is 25MHz.
For the latency, the total time between
a data request and the reception of the answer frame has been evaluated at about 4ms (500-sample average, measured with the Wireshark protocol analyser computing the diff erence between the timestamps of data requests and corresponding answers). Additional evaluations were made to determine which parts of the system are responsible for this delay. Results showed that the main cause is the delay function provided by the RTOS, which allows a minimum delay of 1ms, used to set the interval between write and read operations
Table 1: Measured execution times
automationmagazine.co.uk
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