Rockwell Automation 1794-IE8H, Series B FLEX I/O 8 Input Hart Analog Module Installation Instructions - Manual (Page 29)

FLEX I/O 8 Input HART Analog Module 29
Publication 1794-IN108D-EN-P - January 2014
Field Transmitter Supply Characteristic
The field transmitter supply can be modeled as a 23.7V source with a 273 Ω
series resistance see the Field Transmitter Load Characteristic graph. This
provides a simple and useful mechanism to determine transmitter and loop
compatibility.
The actual transmitter supply contains three ranges of impedance with the
following characteristics:
• The output voltage is ≈ 23.7V for load currents of 0 mA.
• If the load is more than
≈
750 Ω but less than Ω , the transmitter supply
is in a constant resistance region (
≈
273 Ω ).
• For load impedance between 0 and
≈
750 Ω , the transmitter supply
current is controlled by the field device to a maximum of ≈ 22 mA.
Extended
Configuration (1)
Configuration additions are needed for HART communications in Series
A mode. An extended configuration area is provided. This Extended
Configuration table is configured by writing a CIO or MSG instruction
with the following:
Class = 0x7D
Instance = Product location on flexbus (Use 1 for the module
located next to the adapter.)
Attribute = 0x65
Service = Set Attribute Single (0x10)
HART Status
Indicators When this bit is set (1), the status indicators are used for HART
diagnostic. Indicator behavior changes to show communication on
HART. Each indicator represents a HART loop. Flashing yellow indicates
that communication is currently being processed. Solid yellow means
that this device is in the transmitter list.
HART Status Inhibit When this bit is set (1), the HART communication status is not shown in
the realtime data table. The appropriate areas are cleared with zeroes.
Range: 0 = normal, 1 = inhibit HART
50/60 Hz Filter Range: 0 = 50 Hz, 1 = 60 Hz
(1) This Extended Configuration area is for the 1794-IE8H in Series A mode only. Do not attempt to use
this in Series B mode. For more information on how to use these parameters in Series B mode, See
Table Configuration Map on page 13.
Field Descriptions