Reference Manual
00809-0100-4021, Rev FB
August 2011
3-25
Rosemount 3144P
HAR
T
To initiate a Simulation Alarm, follow the steps below with the Traditional
Fast Key sequence:
1. From the Home screen, select
1 Device Setup, 2 Diag/Serv, 1 Test
Device, 1 Loop Test, 3 Simulate Alarm
.
2. The transmitter will display an alarm based on the chosen alarm
conditions.
3. To return the transmitter to normal conditions, select
5 End
.
TRANSMITTER
DIAGNOSTICS LOGGING
View Logging
The Transmitter Diagnostics Logging feature stores advanced diagnostic
information between device resets, such as what caused the transmitter to go
into alarm, even if that event has disappeared. For example, if the transmitter
detects an open sensor from a loose terminal connection, the transmitter will
go into alarm. If wire vibration causes that wire to begin making a good
connection, the transmitter will come out of alarm. This jumping in and out of
alarm is frustrating when trying to determine what is causing the problem.
However, the Diagnostics Logging feature keeps track of what caused the
transmitter to go into alarm and saves valuable debugging time. This
information is available from the field communicator and AMS. The log may
be cleared by selecting “Clear Log,” using Traditional Fast Key sequence 1, 2,
1, 5.
MULTIDROP
COMMUNICATION
Multidropping
refers to the connection of several transmitters to a single
communications transmission line. Communication between the host and the
transmitters takes place digitally with the analog output of the transmitters
deactivated. Many Rosemount transmitters can be multidropped. With the
HART communications protocol, up to 15 transmitters can be connected on a
single twisted pair of wires, or over leased phone lines.
Multidrop installation requires consideration of the update rate necessary from
each transmitter, the combination of transmitter models, and the length of the
transmission line. Communication with transmitters can be accomplished with
Bell 202 modems and a host implementing HART protocol. Each transmitter
is identified by a unique address (1–15) and responds to the commands
defined in the HART protocol. Field Communicators and AMS can test,
configure, and format a multidropped transmitter the same way as a
transmitter in a standard point-to-point installation.
Figure 3-8. Typical Multidropped
Network
Traditional Fast Keys
1, 2, 1, 5
Device Dashboard
Fast Keys
2, 2, 8, 5, 5
Power Supply
Power Supply
Impedance
Handheld Terminal
Computer or DCS
3144P HART
transmitter
4–20 mA
HART Interface
250
Aotewell Ltd
www.aotewell.com
Industry Automation
HongKong|UK|China
+86-755-8660-6182
