Emerson Network Router Instrukcja Użytkownika Pobierz pdf (Strona 20)

14 ProLink

II Software for Micro Motion

Transmitters

Installation and Setup

Figure 2-5 Model 1700/2700 I.S. transmitters: Resistance and voltage requirements for

HART/Bell 202 connections

Figure 2-6 HART/RS-485 connection to transmitter or multidrop network

max

= (V

supply

– 12)/0.023

A minimum of 250 ohms and 17.5 volts is required

Supply voltage VDC (Volts)

External resistance (Ohms)

Operating range

12 3014 16 18 20 22 24 26 28

1000

900

800

700

600

500

400

300

200

100

DCS or

PLC

Attach serial port or USB

adapter if necessary (not

shown)

RS-485 terminals

Transmitter

RS-232 <-> 2-wire RS-485

interface converter

Notes:

• Connect the interface leads to the RS-485 terminals on the transmitter, or to any point on the network.

• Ensure that your transmitter’s RS-485 terminals are configured for HART protocol.

• For RFT9712 transmitters, set the jumper for RS-485 communications.

• For long-distance communication, or if noise from an external source interferes with the signal, add two 120-Ω

terminating resistors (R1) at each end of the RS-485 network.

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Emerson Network Router Instrukcja Użytkownika Strona 20