TSN Ethernet Switches Enable Lower Latency Data Traffic Flows

Microchip Technology Inc

Microchip manufactures connected, smart embedded control solutions. Essentially, it produces integrated computer chips that provide different functions for many applications.

 

The LAN9668x and LAN8814 chips. Image used courtesy of Microchip

 

Recently, Microchip released a new chip for TSN (time sensitive networking) gigabit Ethernet switches. The new chips are primarily used with 8 port and 4 port Ethernet switches for the industrial and commercial market. The LAN9668x and LAN8814 support TSN and provide low latency and end-to-end transmission.

Low Latency

Ethernet communications between devices is an information packet sent from one device to another over the network. Depending on the speed of the switches and the configuration of the network itself, the time to deliver these information packets can vary. This time is referred to as latency within the network.

 

Ethernet switches can be utilized throughout an industrial facility. Image used courtesy of Microchip

 

For most devices on the network, this time to send or receive information packets really doesn’t matter, because their process is not time-dependent. Most networks can send and receive information packets within a few milliseconds, and most Ethernet devices can withstand this latency within the network.

Motion-related tasks require the fastest (i.e., lowest) latency network design because, in a matter of a few milliseconds, a servo motor could travel enough distance to damage components if the motor is not stopped in time. With precise motion control systems, both electrical and hydraulic, extra delays in signal communication can allow product to move further down the line before a command is received by a controller, resulting in lower quality output.

Servo Motors Over Ethernet Networks

In the past, the position of a motor or tooling attached to the motor was determined with a hard-wired encoder. Today, we have servo motors communicating over Ethernet networks using an industrial protocol such as Ethernet/IP or ProfiNet.

 

A UDP cord. Image used courtesy of Jordan Harrsion

 

With these networked servos, the position is sent over the Ethernet network. If that network is subjected to high latencies, the servo motor’s position may not be updated quickly enough. If the servo motor overshoots a position because the control system didn’t notice the servo had moved past a point, damage to the system could occur.

By using network switches with low latency, this potential for damage can be reduced.

Time-Sensitive Networking

The chips from Microchip support TSN requirements including IEEE 1588 v2. This standard protocol ensures clock synchronization of messages sent over an Ethernet network.

TSN-enabled devices, including Ethernet switches, allow for a completely synchronized system. When all the devices on the network are synchronized, they can work together in unison, allowing for motion commands to be executed at exactly the correct moment in time.

Industrial Applications

Servo motors and drive manufacturers utilize the Ethernet network to control motors. By using the Ethernet network to monitor position and speed, manufacturers can offer their customers a more efficient and less hardware-dependent product.

As more of these drives are added to a network, the amount of time-sensitive data sent over the network increases. The switch manufacturers can produce Ethernet switches capable of handling these TSN messages with low latency. This function allows for OEMs and machine builders to use network servo motors without adding additional hardware.

Network servos can have added safety features to control the servo’s speed during specific safe conditions, or ensure all motion has stopped before allowing the safety system to open guard doors. The new Ethernet switch chips from Microchip may facilitate switch manufacturers to produce Ethernet switches capable of running these high-tech motors and applications.