What is the physical layer of fieldbus?
What is the physical layer of fieldbus?
The first and most important layer of the FOUNDATION Fieldbus communication paradigm is the physical layer. It explains how digital data is sent and received over the network wire as electrical impulses. This layer makes sure that all devices have the same electrical and mechanical connection, which makes it easy for them to work together.
The FOUNDATION Fieldbus H1 works using a two-wire, ungrounded cable that has a characteristic impedance of roughly 100 ohms. These lines carry both DC power and digital communication signals, which makes installation easier because each device only needs two connections. The system sends and receives data at a rate of 31.25 kbps and uses differential voltage signaling (0.75 V peak-to-peak minimum for sending and 0.15 V for receiving). Manchester encoding is used to mix data and clock signals, which makes them more reliable and easier to sync up.
A standard Fieldbus H1 segment has a DC power supply, a power conditioner, two terminators (one at each end of the trunk), a shielded twisted-pair trunk cable, and field devices that are connected. You can set up the network in numerous ways, such as daisy-chain, bus, or chicken-foot. However, the bus setup with short spurs is the best for reliability and ease of maintenance.
Termination resistors are very important because they stop signal reflections. The power conditioner separates the DC source from digital noise. People often utilize coupling devices, also called “bricks,” to link several field devices to the main trunk. This makes installation easier. The physical layer is meant for strong communication in tough industrial settings and works with PROFIBUS-PA systems.