= gravitational acceleration | Siemens 7ML19985AB01 specification

BS-3680 THIN PLATE RECTANGULAR WEIR, P3 = 6

‘U’ parameters required *			‘U’ parameters calculated **
U0	= approach width	B	U3	= Ce
U1	= crest width	b	U4	= Kb
U2	= crest height	p

*obtain from manufacturer’s specifications.

**calculated by OCM-3. May be viewed by accessing ‘U’ parameter.

Reference

ABSOLUTE CALCULATION, P4 = 0¤
For flows that can be calculated by the equation:
q = Ce x 2⁄3 ⎯⎯√2⎯g x be x (he)1.5
where : q = flow rate	Ce = a function of h, p, b and B
g = gravitational acceleration	be = effective crest width (b + Kb)
b = crest width	he = effective head (h + Kh)
h = head	Kh = 1 mm
RATIOMETRIC CALCULATION, P4 = 1¤
For flows that can be calculated by the equation:
q = qcal x Ce/Cecal x (h/hcal)1.5

where : q = flow rate

qcal = flow rate at maximum head h = head

hcal = maximum head

Ce = discharge coefficient for head

Cvcal = discharge coefficient for maximum head

¤Refer to Operation \ Flow Calculation.

7ML19985AB01

OCM III

68

Image 67

Siemens 7ML19985AB01 = approach width = Ce = crest width = K b = crest height, = gravitational acceleration

Contents

Open channel Contact Smpi Technical Publications at the following address Unit Repair and Excluded Liability Table of Contents General Keypad Initial Start Up Fundamental Checks Start UPOperation Appendices Maintenance Error Codes 100 Communications 101 7ML19985AB01 OCM Short About thisIf you want to know about Read Product OCM IP65 enclosure Specifications» range 20 or 4-20 mA » resolution » 20 to 50 C -5 to 122 F » CE *, FM, CSA NRTL/C Programmer Transducer Temperature SensorCabling Auxiliary Input Communication SoftwareOutput » Belden Installing the OCM-3 InstallationOutline and Mounting OCM-3 Layout OCM-3 System DiagramCustomer device Ground shield at OCM-3 only Installing the TransducerInstalling the Temperature Sensor Ground shield at OCM-3 only Basic Wiring Temperature Sensor Relays MA Output Synchronization AC Power Power ConnectionsDC Power Communicating VIA Computer Installing the Memory BACK-UP BatteryInstalling the Programmer Disconnect power before installing or replacing the battery General Start UPKeypad English Initial Start UPOCM-3 is asking which language you prefer to communicate Language F13 auto zero calibration 160 Completed 7ML19985AB01 P0 language English P1 dimensional units Centimeters F5 ddmmyyyy date October 12 114124-hr. time 114100 Enter new time Fundamental Checks OCM Units OperationMemory Security = constant Flow CalculationDisplay Absolute vs. ratiometric Damping For battery operation, set display lighting to off or auto » P6 * flow rate For battery operation, have relays energizing on alarmExample For relay » 20 mA Flow Rate and Totalizing FAIL-SAFEFlow rate Capacity Logging Viewing the data log Blanking TemperatureTime and Date Reset Emulation Mode As normal 7ML19985AB01 Flow Velocity InputAuxiliary Head Input Voltage Input Current Input DC Output Diagnostic Aids100% head 4 m, enter 5 m Nominal target range Security access required‘D’ Parameter Listing Velocity OCM ‘F’ Parameter Listing Enter security code Emulation modeKeypad to mA output OCM Linear Velocity ‘P’ Parameter Listing= centimetres = imperial million gallons per day Flowrate Volume= absolute = ratiometric Flow rate units Gallons OCM = 4-20 mA = 0-20 mA 7ML19985AB01 OCM OCM Variable condition FixedUnits OCM ‘U’ Parameters for P3 Primary Element OCM Reference U0 = exponent U1 = k factor P4 = 0 only= constant factor U1 = head Typical Weir Profiles Typical SHARP-CRESTED Weirs Khafagi Venturi Typical Parshall Flume Typical Leopold Lagco ‘U’ parameters required ‘U’ parameters calculated BS-3680 Rectangular Flume = crest width = Cv = crest height = Cd = crest length = a BS-3680 Round Nose Horizontal Crest Weir ¤ Refer to Operation \ Flow Calculation 7ML19985AB01 Cv = velocity coefficient BS-3680 Trapezoidal Flume BS-3680 U-Flume, P3 = BS-3680 U-FLUME = head H and p applied to C = crest width = C = crest height = Cp = crest length BS-3680 Finite Crest Weir = crest width He = effective head h + Kh = head Kh = 1 mm = Ce x 2⁄3 ⎯⎯√2⎯g x be x he1.5 Where q = flow rate= approach width = Ce = crest width = K b = crest height = gravitational acceleration BS-3680 Thin Plate Rectangular Weir U0 = notch angle Alpha U1 = Ce BS-3680 Thin Plate V-NOTCH Weir U0 = crest width b Rectangular Weir Contracted = hydraulic radius = slope of hydraulic gradient Based on the Manning Formula Round Pipe U0 = maximum flume width, hmax PALMER-BOWLUS Flume U0 = maximum listed head, hmax Flume U0 = number of data points n, 4 to Universal Head vs FLOW, P3 = Flow, point A19 Flow, point A13 Head, point A14Flow, point A15 Head, point A16 Flow, point A17 Head, point A18 U0 = channel width B U1 = area h Rectangular Area X Velocity = head, cm = flow velocity, cm/sec Trapezoidal Area X Velocity For h ≥ d = B b/d Where q = flow rate, l/s= channel top width, cm = head, cm = channel base width, cm Modified Trapezoidal Area X Velocity U0 = base diameter D U1 = area h Channel Area x Velocity U0 = conduit diameter U1 = area h Circular Area X Velocity GULL-WING Area X VELOCITY, P3 = Gull Wing Area X Velocity EGG-SHAPED Area X VELOCITY, P3 = EGG-SHAPED Area X Velocity Typical open channel Universal Area X VELOCITY, P3 = Area Head Universal Area X VelocityA10 = OCM Maintenance Error Codes Computer Customer’sSerial printer 102 Protocol for the OCM-3 is as follows Baud rate Refer to Cvcc Instruction DB-9 connectorDB-25 connector Bipolar Current P35 = 7, print interval set for 7 minutes Date104 Remote OCM-3 display Local display Utilities Software Programmer Remote OCM-3 programming105 106 107 Typical OCM-3Display value 00.000000 99.12399.123000 7ML19985AB01 Response # = 0 through Content of P5 Stop data log down load Start data log down load109 Computer Telephone lines Remote modem DB-25 connector 7ML19985AB01Standard modem Cable Connect Establishing Communication111 112 Ending Communication Rev