Comm-Master
(Polling Master for Allen-Bradley PLCs)
The MARC Model 166-001 Comm-Master is a "Polling Master" module for Allen-Bradley Programmable Logic Controllers (PLCs). A Polling Master module collects data from other equipment using a serial data communication port and the communication protocol of the external device. Data collected is written directly to PLC memory for use by the ladder logic programs. The Comm-Master collects the data and writes it to PLC memory with no PLC programming required. Sending data to the external device requires a simple message (MSG) instruction in the PLC.