摘要 |
In a system for performing signal transmission, through a field bus, between field devices and higher-rank apparatuses connected on a transmission line, the field devices are of the analog signal type, and a substitution means is provided between the analog type field devices and the field bus so that the substitution means acts to perform communication on the field bus as a substitute for the field devices. By the substitution means, the field devices can be gradually changed to those adapted to the field bus as occasion demands, so that an existing system can be transformed step by step into a field bus system.
|