Emerson Rosemount OCX8800A - Page 164

control loop. Based on the orifice specification sheet, the differential pressure
transmitter was calibrated for 0 to 20 in. (0 to 508 mm) H
2
0 for a flow of 0 to 800
gal/min. (0 to 3028.3 L/min.), and the transducer was not configured to take the
square root of the differential pressure.
Solution
Table 8-24 lists the appropriate configuration settings, and Figure 8-11 illustrates
the correct function block configuration.
Table 8-24: Analog Input Function Block Configuration for a Differential
Pressure Measurement
Parameter Configured values
L_TYPE Indirect square root
XD_SCALE 0 to 20 in. (0 to 508 mm)
OUT_SCALE 0 to 800 gal/min. (0 to 3028.3 L/min.)
Figure 8-11: Function Block Diagram for a Differential Pressure Transmitter
Used in a Flow Measurement
8.8.17 Troubleshoot
Mode will not leave out of service (OOS)
Potential cause
Target mode not set.
Recommended action
Set the target mode to something other than OOS.
Potential cause
Configuration error.
Recommended actions
BLOCK_ERR shows the configuration error bit set. Set the following
parameters:
a) Set CHANNEL to a valid value; do not leave it at the initial value of 0.
b) Set XD_SCALE.UNITS_INDX to match the units in the transducer block
channel value.
F
OUNDATION
™
Fieldbus Manual
December 2022 00809-0500-4880
164 Emerson.com/Rosemount