“Recently, Microchip released a chip for TSN (Time Sensitive Networking) Gigabit Ethernet switches. The new chips are primarily intended for 8-port and 4-port Ethernet switches in the industrial and commercial markets. The LAN9668x and LAN8814 support TSN and provide low latency and end-to-end transmission.

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Recently, Microchip released a chip for TSN (Time Sensitive Networking) Gigabit Ethernet switches. The new chips are primarily intended for 8-port and 4-port Ethernet switches in the industrial and commercial markets. The LAN9668x and LAN8814 support TSN and provide low latency and end-to-end transmission.

LAN8814 block diagram

Application of LAN8814 in Switch

low latency

Ethernet communication between devices is the sending of information from one device to another over a network. Depending on the speed of the switch and the configuration of the network itself, the time to deliver these packets may vary. This time is called latency within the network.

Ethernet switches can be used throughout industrial facilities.Image courtesy of Microchip

For most devices on the network, the time at which a packet is sent or received is not important because their process is not time-dependent. Most networks can send and receive packets in milliseconds, and most Ethernet devices can tolerate this latency within the network.

Motion-related tasks require the fastest (i.e. lowest) latency network design, because servo motors can move enough distances in a few milliseconds to damage components if the motors are not stopped in time. With a precise motion control system (both electrical and hydraulic), additional delays in signal communication can cause the product to move further down before the controller receives a command, resulting in lower output quality.

Servo motor on ethernet

In the past, control of a motor or connected to a motor was determined by hard-wired encoders. Today, our servo motors communicate over Ethernet using industrial protocols such as Ethernet/IP or ProfiNet.

A UDP line.Image courtesy of Jordan Harrsion

Using these networked servos, position information can be sent over Ethernet. If this network latency is high, the position of the servo may not be updated fast enough. If the servo motor pushes the mechanical part beyond a certain position because the control system doesn’t notice that the servo has moved past a certain point, it can damage the system.

This potential damage can be reduced by using network switches with low latency.

Time Sensitive Networking TSN

Microchip’s chips support TSN requirements, including IEEE 1588 v2, a standard protocol that ensures clock synchronization for messages sent over Ethernet.

Devices that support TSN, including Ethernet switches, enable a fully synchronized system. When all devices on the network are in sync, they work together, allowing motion commands to be executed at the exact time.

Industrial application

Servo motor and drive manufacturers utilize Ethernet networks to control motors. By using Ethernet to monitor location and speed, manufacturers can provide their customers with products that are more efficient and less dependent on hardware.

As more and more drives are added to the network, the amount of data sent over TSN also increases. Switch manufacturers can produce Ethernet switches that can process these TSN messages with low latency. This feature allows OEMs and machine builders to use networked servo motors without adding additional hardware.

Networked servos can add safety features to control the speed of a servo under certain safety conditions, or to ensure that all motion has stopped before allowing the safety system to open a protective door. Microchip’s new Ethernet switch chips may help switch manufacturers produce Ethernet switches capable of running these high-performance motors.