Page 57
RATIOMETRIC
V-Notch Angle Weir (Non BS 3680)
If the flow calculation is to be ratiometric P702 = 2 the flow will be
calculated using the formula: q= q
cal
(h+kh/h
cal
+kh)
2.5
Where: q = flowrate
q
cal
= flowrate at maximum head P705
h = head
kh = compensated head
Universal Calculations
Point of Measurement
The transducer must be above the maximum head P704 by at least the near
blanking distance P107.
For all Universal calculation applications the point at which the head is
measured should be chosen such that the surface of the liquid is not affected
by turbulence.
Calculations
ABSOLUTE
Universal Head Vs Flow
If the flow calculation is to be absolute P702 = 1 the flow will be calculated
using the formula: q = q(h)
Where: q = flowrate
q(h) = flowrate for head
The desired number of Breakpoints, (P730 - P793) are to be entered in
pairs in values of head and corresponding flow. (Minimum of 2 pairs of
Breakpoints is required).