Caching process data of a slow network in a fast network environment

摘要

A caching method and system for a control system having a fast network and a slow network that each contain devices involved in the control of a process is disclosed. The cache is disposed in a gateway interface device interconnected with both the fast and the slow networks. The cache is populated only in response to requests of clients connected in the fast network but is refreshed independently of the fast network. To reduce traffic on the slow network, the cache is populated with a collection of parameters to which a requested parameter belongs. This avoids a round trip on the slow network for future requests of the requested parameter and other members of the collection. A parameter is removed from cache if an associated expiration timer expires before a further request therefor is received. Cache refresh is variable based on loading of the slow network and responsiveness of the devices of the slow network.