MGS-250 Manual
6490-9000 Revision 4
27
3.5. Modbus Network Configuration
If your application includes a Modbus network, make network
connections (RS-485 A and RS-485 B) using 18 to 24 AWG shielded
twisted pair wires (with 120 ohm characteristic impedance) to terminal
block positions 7 and 8 (see Figure 12), noting inverted B (-) and non-
inverted A (+) signal connectors per Table 8.
Figure 12. Modbus Network Wiring
Table 8: Modbus Network Communications Connections
Function
Pin
Wiring Termination
Modbus Network
Communications
7
RS-485 “B” (inverted)
8
RS-485 “A” (non-inverted)
9 RS-485
shield
IMPORTANT:
For Modbus network communications wiring,
use only 18-24 AWG shielded twisted pair wire with 120 ohm
characteristic impedance.
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