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1/99 SMV 3000 Transmitter User’s Manual 81
7.3 Running Output Check
Background
An SMV transmitter operating in the analog mode can be put into a
constant-current source mode (called the output mode) to checkout other
instruments in the control loop such as recorders, controllers, and
positioners. Using the SCT, you can tell the transmitter to change its
output to any value between 0 percent (4mA or 1V) and 100 percent
(20mA or 5V) and maintain that output. This makes it easy to verify loop
operation through the accurate simulation of transmitter output signals
before bringing the loop on-line.
For SMV transmitters operating the DE mode, you can simulate an output
for each PV individually to verify output at the digital receiver or DCS.
Follow the steps in Table 20 for transmitters in DE mode.
ATTENTION
The transmitter does not measure the given PV input or update the PV
output while it is in the output mode.
Analog Output Mode
Procedure
IMPORTANT: Before performing this procedure, you must check the
calibration of the transmitter’s D/A converter. Perform
the procedure “The Steps to Calibrate for PV4 Output,”
found in the Calibration section of the SCT on-line user
manual.
The procedure in Table 19 outlines the steps for checking the PV output
for SMV transmitter operating in analog mode.
Table 19 Analog Output Check Procedure
Step Action
1
Connect SCT to SMV and establish communications. (See
Subsection 5.2 for procedure, if necessary.)
2
Be sure any switches that may trip alarms or interlocks associated
with analog loops are secured or turned off.
3
Perform Upload of the SMV database to the SCT.
4
Select General tab card and set communication mode to Analog.
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