Instruction Manual

Instruction Manual
D102748X012
Configuration
October 2014
45
gravity value, select Single Point and enter the specific gravity value. To display or enter values in the tables, select Table
of SG vs T.
The Field Communicator begins by prompting for the temperature of the first pair in the lower table. After entering
the temperature for the first pair, press ENTER. Enter the specific gravity for the first pair and press ENTER. The Field
Communicator then prompts for the temperature for the second pair. Enter this temperature and press ENTER. The
Field Communicator then prompts for the specific gravity for the second pair. Continue entering each temperature
and specific gravity pair. When finished, enter zero at the Field Communicator prompt for the next specific gravity
value to exit the table. For level applications, the Field Communicator exits to the Instrument Setup menu. For interface
applications, the Field Communicator prompts for the first temperature and specific gravity pair for the upper table.
Enter Constant Density— Enter the density of the process fluid
Measure Density— Select OK to measure the differential density between lower and upper phases of the process fluid.
Note
Measure Density is only visible if PV is Level.
If the instrument and sensor are calibrated, you can have the digital level controller measure the liquid specific gravity,
if it is not known. You must be able to manipulate the level and externally measure it to have the instrument measure
the specific gravity. To work properly, this procedure must be in done in Level measurement mode, and a valid dry
coupling reference must have been obtained at the zero buoyance condition. Use as high a test level as possible to
improve accuracy. Follow the prompts on the Field Communicator and the following procedure to measure specific
gravity:
1. Set the control loop for manual control.
2. Adjust the liquid level so that the displacer is partially submerged.
3. Enter the externally measured level, in engineering units.
After you press OK on the Field Communicator, the instrument begins calculating the specific gravity. You can then
elect to use this value as the specific gravity for all level measurements. If you select No, the instrument uses the
specific gravity entered under PV Setup, or the values from the specific gravity tables.
4. When finished measuring specific gravity, return the control loop to automatic control.
D Load Steam Tables
Note
Load Steam Tables is only visible if PV is Interface.
Table 4‐3 lists example entries for saturated steam. Figure 4‐5 is the curve that results when these values are plotted.
Table 4‐3. Example Specific Gravity vs Temperature Table for Saturated Steam
DATA POINT
TEMPERATURE
SPECIFIC GRAVITY
_C _F
1
2
3
4
5
126.7
210.0
271.1
304.4
326.7
260
410
520
580
620
0.00095
0.00850
0.02760
0.04900
0.07200
6
7
8
9
10
343.3
357.8
365.6
371.1
374.4
650
676
690
700
706
0.09800
0.13500
0.16800
0.21000
0.31570