Bus nodes

PROFIBUS DP distinguishes between two different master classes and one slave class:

DP master Class 1

For PROFIBUS DP, DP master Class 1 is the central component. In a defined message cycle that always repeats itself, the central master station exchanges information with distributed stations (DP slaves).

DP master Class 2

When commissioning, to configure the DP system, for diagnostics or to operate the plant or system in operation, devices of this type are used (programming, configuring or operator control devices). A DP master Class 2 can be used, for example, to read the input, output, diagnostic and configuration data of the slaves.

DP slave

A DP slave is an I/O device, which receives output information or setpoints from the DP master, and as response, returns input information, measured values and actual values to the DP master. A DP slave never sends data automatically, but only when requested by the DP master. The quantity of input and output information depends on the device, and for each DP slave in each send direction can be a maximum of 244 bytes.