Limitations of ethernet
Maximum span of 328 feet (100m)
Copper cable is susceptible to EMI -Common sources:switching of large loads -eg: motor starters,VFD,etc…
Ground faults can occur between equipment -Occur when grounds are at different potentials. -May be intermittent or life threatening -Within a control panel use single-point grounds
No inherent protection from catastrophic events -Lightning can propagate through copper cat5 cable
Network controllers may use one or more of these. 1. Polling, that is, the microprocessor checks the state of peripheral devices under the control of the program. Industrial Ethernet is used for industrial Ethernet, in general, Ethernet is the use of TCP/IP protocol.
In the field bus protocol, in order to improve the transmission efficiency, only the physical layer, data link layer and application layer are defined. To integrate with Ethernet, IP addresses are usually added before packets and data is transmitted over TCP.