Emerson 5300, 5400 specifications RS-485 Bus, Installation cases

Manual Supplement

00809-0500-4530, Rev AA October 2010

Rosemount 5300/5400 Series

RS-485 Bus

•The 5300/5400 transmitters do not provide electrical isolation between the RS-485 bus and the transmitter power supply

•Maintain a bus topology and minimize stub length

•Figure 1-4 identifies multidrop wiring topology, where up to 32 devices may be wired on one RS-485 bus

•The RS-485 bus needs to be terminated once at each end, but should not be terminated elsewhere on the bus

Installation cases

Install the Rosemount 5300/5400 Series Transmitters as shown in Figure 1-4.

•Use common ground for Modbus Master and Power Supply

•The Power cables and RS-485 Bus are in the same cable installation

•An ground cable is installed and shall be used (cable size ≥4 mm according to IEC60079-14, or size according to applicable national regulations and standards). A properly installed threaded conduit connection may provide sufficient ground.

•The cable shielding is grounded at master site (optional)

NOTE

The HMC equipped transmitter contains intrinsically safe circuits that require the housing to be grounded in accordance with national and local electrical codes. Failure to do so may impair the protection provided by the equipment.

Figure 1-4. Multidrop Connection of 5300/5400 Transmitters

120Ω RS-485 Bus

HART to Modbus Converter

MB

	MODBUS MA	-
	(RS-485)
-	POWER	+
	HART Ambients > 60 ºC
+	Use wiring rated
	for min 90 ºC

HART to Modbus Converter

MB

	MODBUS MA	-
	(RS-485)
-	POWER		+
	HART Ambients > 60 ºC
+	Use wiring rated
	for min 90 ºC

120Ω

BModbus

A Master

Z

Power

Supply

Internal		Internal
Ground Screw	External	Ground Screw	External
	Ground Screw		Ground Screw

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