Ethernet is envisaged as a de facto standard for communication but its usage at field instrument level is not commonly in vogue. I mean, at instrument level bus networks like Fieldbus, Modbus, CANbus, are mostly implied renouncing ethernet despite its COTS trait.

Would anybody help me to get out of this fix?

 

The CAN (and other similar) networks are targeted at low I/O count applications, while Ethernet does everything else. The CAN type networks allow for simpler hardware at the device node and simpler cabling, but they have very limited capacity. In other words, you would use Ethernet to an I/O rack or block, but a CAN or ASI network to an individual sensor or relay.

It's not an either/or choice. You can use both in different parts of the same system, and connect them together using gateways.

There are also some other networks that are targeted at process industries, due to special requirements there.