Precision Digital PD865 - Manual (Page 59)

PD865 Snooper Modbus Serial Input Meter Instruction Manual
59
OPERATION
The PD865 meter is capable of operating as a Modbus Master, Slave or
Snooper. As a Slave, the PD865 requires connection to a Master
device: PLC, DCS, etc. As a Master, the PD865 interfaces up to eight
slave devices. As a Snooper it can be connected anywhere in the
RS-485 bus to read any of the variables being requested by the Master
device.
Master and Slave Connections
The following figures show a few possible connection schemes.
Figure 12: PD865 Slave & Snooper Connected to a Master
Figure 13: PD865 Master Connected to a Smart Sensor & Chart
Recorder