Precision Digital PD6730X - Manual (Page 17)

PD6730X Vantageview Super Snooper Modbus Scanner Instruction Manual
17
RS-485 Signal Connections
The scanner includes a three-wire RS-485 serial connection. The cabling used for an RS-485 serial
communications network should always be a high quality cable such as Belden 8162 or Alpha 6203C. A
three-wire system requires two twisted pairs (the extra twisted pair is needed for the signal ground).
Figure 2: RS-485 Three-Wire Serial Connections
Figure 3: RS-485 Five-Wire Serial Connections
DC Power Connection
DC power is wired to terminals P+ and COM as shown in Figure 5. The same power supply may be used
to power other circuits including a PNP-type sensor, however to maintain input isolation, a separate
power supply must be used to power the isolated 4-20 mA transmitter as shown in Figure 6 and/or to
power the Opto-Isolated Flowmeter as shown in Figure 9.
Figure 4: DC Power Connections
Power
Supply
COM RST P+ S+ S-