APG DCR-1004 user manual - Manual (Page 34)

DCR-1003 and DCR-1004 Rev. A3, 10/08
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Example 8: Weir
The inlet flow to an irrigation reservoir is to be monitored and displayed in
cubic feet per second (CFS). A 5 ft. rectangular weir without end contractions is
to be used as the primary measuring device.
The associated flow equation for the 5 ft. weir is:
Flow in CFS = 16.65 * H^1.5
where H = the height of the pool above the weir crest
By mounting the DST sensor more than 2.00 ft. above the maximum pool
height, and locating the sensor upstream from the weir crest as recommended
for this weir type, the flow can be calculated.
*NOTE: The DCR-1004 does NOT work with contracted-end weirs.
To program the DCR-1003, 1004 for this application, the following modes
must be set:
MODE VALUE DESCRIPTION
Operation
3 4 Select Open Channel Monitoring for application
5 2.00 Do not set closer than the minimum distance
recommended for the DST sensor type being used
Open Channel Flow
38 16 Constant ‘K’ above the decimal point
39 6500 Constant ‘K’ below the decimal point
40 .00 Secimal to two places
41 SPAN Distance from .5 in. behind the transducer face to the top of the
weir crest using a tape measure
42 1 Exponent ‘X’ above the decimal point
43 5000 Exponent ‘X’ below the decimal point