Siemens SITRANS LUT400 - Open Channel Monitoring (OCM)

General Operation
7.11 Open Channel Monitoring (OCM)
SITRANS LUT400
Operating Instructions, 07/2019, A5E33329501-AC
121
Parameter
Value
Description
Assigned Relay (2.11.4.5.)
(Page 217)
Relay 1 Sets relay 1 to be controlled by external sam-
pler.
Relay Logic (2.11.4.6.)
(Page 217)
Normally
Closed
Use (if necessary) to change the behaviour of
the relay assigned to the sampler.
Default: Normally Open
During the periods of low flow, the sampler may be idle for lengths of time. Program Interval
(2.11.4.3.) (Page 217) time in hours to drive the sampler. The sampler will operate based on
the volume of flow or the time interval, whichever comes first.
7.11 Open Channel Monitoring (OCM)
An OCM installation is defined one of three ways, based on the Primary Measuring Device
(PMD):
1. Dimensional
For some common weir and flume types. PMD dimensions (PMD Dimensions (2.15.4.)
(Page 234)) are entered directly.
Vessel Type
BS- 3680 Rectangular Flume (Page 131)
BS- 3680 Round Nose Horizontal Crest Weir (Page 133)
BS- 3680 Trapezoidal Flume (Page 134)
BS- 3680 U-Flume (Page 135)
BS- 3680 Finite Crest Weir (Page 137)
BS- 3680 Thin Plate Rectangular Weir (Page 139)
BS- 3680 Thin Plate V-Notch Weir (Page 141)
Rectangular Weir Contracted (Page 143)
Round Pipe (Page 144)
Palmer Bowlus Flume (Page 145)
H-Flume (Page 146)
2. Exponential
For most other weir and flume types. PMD exponents provided by the manufacturer are
entered. Flow is calculated using the exponent (Flow Exponent (2.15.3.2.) (Page 231)) and
the maximum values (Maximum Head (2.15.3.3.) (Page 232) and Maximum Flow at 20 mA
(2.15.3.4.) (Page 232) at 20 mA).
Vessel Type
Standard Weirs (Page 124)
Parshall Flume (Page 126)
Leopold Lagco Flume (Page 127)
Cut Throat Flume (Page 128)