Spectrex 20/20MPI - Commercial IR3 Flame Detector - Manual (Page 54)

SharpEye TM IR3 Flame Detector User Guide
42 Wiring Terminal 20/20MPI-M
A.2 Wiring Terminal 20/20MPI-M
Figure 8: Wiring Terminal 20/20MPI-M
8.5.3
RS-485 Communication Network
Using the RS-485 network capability of the IR3 detector and control
software you can connect up to 32 detectors in an addressable system with
only 4 wires (2 for power and 2 for communication). Using repeaters, the
number of detectors can be much larger (32 detectors for each repeater) up
to 247 on the same 4 wires. When using the RS-485 network, you can read
each detector status (FAULT, WARNING, ALARM) and to initiate a BIT to
each detector individually.
For more details, consult the factory.