Reference Manual
00809-0100-4664, Rev BA
January 2010
4-15
Rosemount 8712
NOTE
Attempting a digital trim without a Rosemount 8714D Calibration Standard
may result in an inaccurate transmitter, or a “DIGITAL TRIM FAILURE”
message may appear. If this message occurs, no values were changed in the
transmitter. Simply power down the Rosemount 8712 to clear the message.
To simulate a nominal sensor with the Rosemount 8714D Calibration
Standard, you must change the following four parameters in the Rosemount
8712:
1. Tube Calibration Number—1000015010000000
2. Units—ft/s
3. PV URV—20 mA = 30.00 ft/s
4. PV LRV—4 mA = 0 ft/s
5. Coil Drive Frequency—5 Hz
The instructions for changing the Sensor Calibration Number, Units, PV URV,
and PV LRV are located in “Basic Setup” on page 3-8. Instructions for
changing the Coil Drive Frequency can be found on page 4-16 in this section.
Set the loop to manual, if necessary, before you begin. Complete the following
steps:
1. Power down the transmitter.
2. Connect the transmitter to a Rosemount 8714D Calibration Standard.
3. Power up the transmitter with the Rosemount 8714D Calibration
Standard connected and read the flow rate. The electronics need
about a 5-minute warm-up time to stabilize.
4. Set the 8714D Calibration Standard to the 30 ft/s (9.1 m/s) setting.
5. The flow rate reading after warm-up should be between 29.97 (9.1
m/s) and 30.03 ft/s (9.2 m/s).
6. If the reading is within the range, return the transmitter to the original
configuration parameters.
7. If the reading is not within this range, initiate a digital trim with the LOI
or Handheld Communicator. The digital trim takes about 90 seconds
to complete. No transmitter adjustments are required.
Auto Zero
The auto zero function initializes the transmitter for use with the 37 Hz coil
drive mode only. Run this function only with the transmitter and sensor
installed in the process. The sensor must be filled with process fluid at zero
flow. Before running the auto zero function, be sure the coil drive mode is set
to 37 Hz (Auto Zero will not run with the coil drive frequency set at 5 Hz).
Set the loop to manual if necessary and begin the auto zero procedure. The
transmitter completes the procedure automatically in about 90 seconds. A
symbol appears in the lower right-hand corner of the display to indicate that
the procedure is running.
Field Comm. 1, 2, 5, 4
LOI Key AUX. FUNCTION
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