Siemens sitrans PROBE LU - Page 45

A5E32337695 SITRANS Probe LU (HART) – OPERATING INSTRUCTIONS Page 39
Parameters
Head Breakpoints
When measuring flow in an open channel device, you can define the cross-section of the
channel as a series of segments. In P054 you assign a head value to each breakpoint. In
P055 you assign a corresponding flow value to each breakpoint.
Enter up to 32 head breakpoints, where the corresponding flow is known. The 100% and
0% levels must be entered. The breakpoints can be ordered from top to bottom, or the
reverse.
1. First set P050 to 9.
2. Select P054.
3. The default breakpoint value appears, with
the breakpoint number in the auxiliary
reading.
4. Press DISPLAY twice to focus control on the secondary index
1
(the auxiliary
reading field goes blank).
5. Key in 1 and press ENTER .
6. Key in the head value for breakpoint 1, and press ENTER . (Use units defined in
P005.)
7. Press the UP ARROW key to display 02 in the auxiliary reading.
8. Key in the head value for breakpoint 2, and press ENTER .
9. Repeat steps 7 and 8 until head values have been entered for all the required
breakpoints.
10. Press DISPLAY twice and use the UP ARROW key to go to P055.
Example: v-notch weir:
Primary Index
P054
Secondary Index
Breakpoint number
Values
Range 0.0000 to 99999 in units (P005)
Default 0.000
Related Parameters
P055 Flow Breakpoints
1.
For more details on secondary index operation, see page 30.
Note: Illustrated values for P054 and P055 are for example purposes only.
breakpoint
value field
breakpoint
number
4
Breakpoints
3
2
Break
-point
Head
(P054)
Flow
(P055)
4 0.4 m 113.5
30.3 m55.3
2 0.2 m 20.07
10 m 0
1
flow characterization
4
2
1
3
42
1
3
head
flow