Siemens 7ML19985AB01 instruction manual = crest width = C = crest height = Cp = crest length

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BS-3680 FINITE CREST WEIR, P3 = 5
‘U’ parameters required *			‘U’ parameters calculated **
U0	= crest width	b	U3	= C
U1	= crest height	p	U4	= Cp
U2	= crest length	L

*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 = (2/3)1.5 x g0.5 x C x Cp x b x h1.5

where :	q = flow rate	C = a function of h and L
	g = gravitational acceleration
	b = crest width	Cp = a correction factor as a function
	h = head	of h and p applied to C
RATIOMETRIC CALCULATION, P4 = 1¤
For flows that can be calculated by the equation:
q = qcal x C/Ccal x Cp/Cpcal x (h/hcal)1.5
where :	q = flow rate
	qcal = flow rate at maximum head
	h = head

hcal = maximum head

C = discharge coefficient for head

Ccal = discharge coefficient for maximum head

Cp = correction factor for C

Cpcal = correction factor for Ccal

¤Refer to Operation \ Flow Calculation.

7ML19985AB01

OCM III

66

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Contents Open channel Contact Smpi Technical Publications at the following address Unit Repair and Excluded LiabilityTable of Contents Operation Start UPGeneral Keypad Initial Start Up Fundamental Checks Appendices Maintenance Error Codes 100 Communications 101 7ML19985AB01OCM If you want to know about Read Product About thisShort OCM » range 20 or 4-20 mA » resolution Specifications» 20 to 50 C -5 to 122 F IP65 enclosure» CE *, FM, CSA NRTL/C ProgrammerCabling Temperature SensorTransducer Output » Belden Communication SoftwareAuxiliary Input Outline and Mounting InstallationInstalling the OCM-3 OCM-3 Layout Customer device System DiagramOCM-3 Installing the Temperature Sensor Installing the TransducerGround shield at OCM-3 only Basic Wiring Temperature Sensor Ground shield at OCM-3 onlyRelays MA OutputSynchronization DC Power Power ConnectionsAC Power Installing the Programmer Installing the Memory BACK-UP BatteryDisconnect power before installing or replacing the battery Communicating VIA ComputerKeypad Start UPGeneral OCM-3 is asking which language you prefer to communicate Initial Start UPLanguage EnglishF13 auto zero calibration 160 Completed 7ML19985AB01 P0 language English P1 dimensional units Centimeters24-hr. time 1141114100 Enter new time F5 ddmmyyyy date October 12Fundamental Checks OCM Memory OperationSecurity UnitsDisplay Flow CalculationAbsolute vs. ratiometric = constantDamping For battery operation, set display lighting to off or autoExample For relay For battery operation, have relays energizing on alarm» 20 mA » P6 * flow rateFlow rate FAIL-SAFEFlow Rate and Totalizing Capacity LoggingViewing the data log Time and Date TemperatureBlanking Reset Emulation ModeAuxiliary Head Input Flow Velocity InputVoltage Input Current Input As normal 7ML19985AB01100% head 4 m, enter 5 m Diagnostic AidsDC Output ‘D’ Parameter Listing Security access requiredVelocity Nominal target rangeOCM Keypad to mA output Enter security code Emulation mode‘F’ Parameter Listing OCM = centimetres ‘P’ Parameter ListingLinear Velocity = absolute = ratiometric Flow rate units Flowrate VolumeGallons = imperial million gallons per dayOCM = 4-20 mA = 0-20 mA 7ML19985AB01 OCM OCM Units FixedVariable condition OCM ‘U’ Parameters for P3 Primary Element OCM = constant factor U1 = head U0 = exponent U1 = k factor P4 = 0 onlyReference Typical Weir Profiles Typical SHARP-CRESTED WeirsKhafagi 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 coefficientBS-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 lengthBS-3680 Finite Crest Weir = approach width = Ce = crest width = K b = crest height = Ce x 2⁄3 ⎯⎯√2⎯g x be x he1.5 Where q = flow rate= gravitational acceleration = crest width He = effective head h + Kh = head Kh = 1 mmBS-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 FormulaRound 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 A15 Head, point A16 Flow, point A13 Head, point A14Flow, point A17 Head, point A18 Flow, point A19U0 = channel width B U1 = area h Rectangular Area X Velocity = head, cm = flow velocity, cm/sec Trapezoidal Area X Velocity = channel top width, cm = head, cm = channel base width, cm = B b/d Where q = flow rate, l/sFor h ≥ d 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 =A10 = Universal Area X VelocityArea Head OCM Maintenance Error Codes Serial printer Customer’sComputer 102 Protocol for the OCM-3 is as follows Baud rateDB-25 connector DB-9 connectorBipolar Current Refer to Cvcc Instruction104 DateP35 = 7, print interval set for 7 minutes 105 Utilities Software Programmer Remote OCM-3 programmingRemote OCM-3 display Local display 106 Display value Typical OCM-300.000000 99.12399.123000 7ML19985AB01 107Response # = 0 through Content of P5109 Start data log down loadStop data log down load Standard modem DB-25 connector 7ML19985AB01Cable Computer Telephone lines Remote modem111 Establishing CommunicationConnect 112 Ending CommunicationRev