1785-PFB

The 1785-PFB is a Profibus DP communication module manufactured by Allen-Bradley. The 1785-PFB communication module is part of Series B of the PLC-5 Profibus modules. This communication module features a remote input-output scanner, an LED display, an RS-232 serial port for connecting cables, an RS-485 interface, and it is applicable in PLC-5 processors. The  1785-PFB communication module is suitable for high-speed data exchange between automation applications and the peripherals which are distributed like remote I/O chassis. The 1785-PFB communication module is more efficient in critical communication; it features 2 key components: a DP slave unit, and a DP master unit to achieve efficient operation. The DP master is designed for requesting data from the DP slave unit. The DP slave unit is designed for responding to the request made by the DP master unit, enhancing the organized structure of operations.

The Allen-Bradley 1785-PFB communication module’s working mechanism is limited to offering the capability of detecting and reporting a duplicate station address between the DP master unit and DP slave unit. It is not recommended to install, remove, or wire the module while the power is supplied to the chassis. This module's network makes use of polling principles in communication; resembling a cyclic exchange of information which is independently achieved when the actual updating of the database by the DP master and the DP slave system takes place. The DP master unit should be equipped with sets of parameter and configuration data for each DP slave unit in order to exchange I/O data with the DP slave units on the network protocol. The data carries all the relevant information required to configure the DP slave unit. The DP master’s parameter data consists of bus parameters and also of an address table for assignments.