A system for monitoring field devices operating in process plants includes a remote terminal unit (RTU) coupled to several field devices, each configured to perform a respective function in a process plant, and a host disposed remotely from the RTU and coupled to the RTU via a communication network. The RTU includes (i) a first interface module configured to communicate according to a digital industrial automation protocol, via which the RTU receives data indicative of respective statuses of the field devices, (ii) a memory to store the received data, and (iii) a second interface module configured to communicate with remote hosts via a communication network. The host is configured to (i) request the statutes of the field devices and (ii) receive, from the RTU, indications of the status based on the data stored in the memory of the RTU.