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Reference Manual
00809-0100-4027, Rev AA
December 2005
3-19
Rosemount 4500
Loop Test The Loop Test command verifies the output of the transmitter, the integrity of
the loop, and the operations of any recorders or similar devices installed in the
loop.
HART Communicator
To initiate a loop test, perform the following procedure:
1. Connect a reference meter to the transmitter by either connecting the
meter to the transmitter test terminals, or shunting transmitter power
through the meter at some point in the loop.
2. From the HOME screen, enter the fast key sequence for “Loop Test” to
verify the output of the transmitter.
3. Select OK after the control loop is set to manual (see “Setting the Loop
to Manual” on page 3-2).
4. Select a discrete milliamp level for the transmitter to output. At the
CHOOSE ANALOG OUTPUT prompt select 1: 4mA, select 2: 20mA, or
select 3: “Other” to manually input a value.
a. If you are performing a loop test to verify the output of a transmitter,
enter a value between 4 and 20 mA.
b. If you are performing a loop test to verify alarm levels, enter the
milliamp value representing an alarm state (see Tables 3-1, 3-3, and
3-2 on page 3-12).
5. Check the reference meter installed in the test loop to verify that it
displays the commanded output value.
a. If the values match, the transmitter and the loop are configured and
functioning properly.
b. If the values do not match, the current meter may be attached to the
wrong loop there may be a fault in the wiring, the transmitter may
require an output trim, or the reference meter may be
malfunctioning.
After completing the test procedure, the display returns to the loop test screen
to choose another output value or to end loop testing.
Fast Keys
1, 2, 2