Smv Modbus Half-Duplex Modbus (Rs-485) Wiring Procedure; Figure 17 - Wiring Details For Smv Modbus Terminal Block; Table 10 - Wiring Details For Smv Modbus Terminal Block - Honeywell SMV800 SmartLine User Manual

Wiring details for SMV Modbus terminal block has been summarized below:
Terminal Number
A wire from the earth ground clamp (refer Figure 12) of Transmitter must be connected to
Earth Ground to make the Lightening protection effective. Use a size 8 AWG or (8.37mm
bare or green covered wire for this connection.

5.3.5 SMV Modbus Half-Duplex Modbus (RS-485) Wiring Procedure

The Modbus A, Modbus B & Modbus common inputs are applied to terminals Terminal #3,
Terminal #4 & Terminal #9 respectively. A 3-wire approach for Modbus communication is
recommended to avoid potential difference related issues & to ensure error-free communication
between drivers and receivers. For Modbus communication, minimum 24 AWG shielded twisted
pair cable with nominal characteristic impedance of 120 ohm is recommended. Shield of the
communication cable must be connected to chassis ground on host side.
Modbus RS-485 network recommends using Termination on either side of the network. Typically,
120 Ohm DC termination on either end (Host side & at last device) are provided.
Alternately "AC Termination" feature can be enabled internal to the device (refer
Table 25), when transmitter is the last device in the network. In this case external termination (if
any) at the transmitter end needs to be removed. Multiple termination (apart from both ends of the
Page 24
Figure 17 – Wiring Details for SMV Modbus Terminal Block
Table 10 – Wiring details for SMV Modbus Terminal Block
1 Power Supply input +ve
2 Power Supply input -ve (Return)
3 Modbus (RS-485) A
4 Modbus (RS-485) B
5 Temperature Sensor Input
6 Temperature Sensor Input
7 Temperature Sensor Input
8 Temperature Sensor Input
9 Modbus (RS-485) Common
SMV800 Transmitter User's Manual
Description
2
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Figure 22,
Revision 10