Emerson Rosemount 3490 Series, Reference Manual

Page: 148 / 190

Fuse
200 mA(T), 5
×
20 mm, 250 V
A.3.2 DC power supply input
15 to 30 Vdc, 30 Vdc maximum
Power consumption
9 W maximum
A.3.3 Current input
4–20 mA (Earth referenced in control unit) or HART digital communications (Rev. 5, 6, and
7).
One HART transmitter on the Rosemount 3491 and 3493, and two HART transmitters on
the Rosemount 3492.
A.3.4 Load limitations
The Rosemount 3490 Series provides an intrinsically safe power supply to an intrinsically
safe approved transmitter mounted in a hazardous area. The control unit provides a
nominal 24 Vdc supply, but this output varies at the terminals depending on electrical load
conditions (see
Table A-1 ).
Table A-1: Minimum Terminal Output Voltages
Load current (mA) Rosemount 3490 Series
terminal voltage (Vdc) Maximum loop resistance
(Ohms)
3.75
(1)
20.9 2370
4.0 20.8 2195
20.0 13.9 95
21.75
(2)
13.5 50
22.5
(3)
12.8 35
(1) Minimum fault current.
(2) Maximum output (Rosemount standard fault level).
(3) Maximum output (NAMUR NE43 fault level).
A.3.5 Trigger inputs
Two voltage-free contact closures
Specifications and reference data Reference Manual
January 2021 00809-0100-4841
148 Emerson.com/Rosemount