U0 = notch angle Alpha U1 = Ce | Siemens 7ML19985AB01 guide

BS-3680 THIN PLATE V-NOTCH WEIR, P3 = 7

‘U’ parameters required *		‘U’ parameters calculated **
U0 = notch angle	alpha	U1 = Ce

*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 8/15 x tan(α/2) x (2g)0.5 x h2.5
where : q = flow rate	h = head
g = gravitational acceleration	Ce = function of h and α

α= notch angle alpha◊

◊angle is restricted to 90°, 53.133° or 28.066°. Otherwise use ratiometric calculation.

RATIOMETRIC CALCULATION, P4 = 1¤

For flows that can be calculated by the equation:

q = qcal x Ce/Cecal x (h/hcal)2.5

where : q = flow rate

qcal = flow rate at maximum head h = head

hcal = maximum head

Ce = discharge coefficient for head

Cecal = discharge coefficient for maximum head

¤Refer to Operation \ Flow Calculation.

7ML19985AB01

OCM III

70

Image 69

Siemens 7ML19985AB01 instruction manual U0 = notch angle Alpha U1 = Ce

Contents

Open channel Contact Smpi Technical Publications at the following address Unit Repair and Excluded Liability Table of Contents Start UP General Keypad Initial Start Up Fundamental ChecksOperation Appendices Maintenance Error Codes 100 Communications 101 7ML19985AB01 OCM About this ShortIf you want to know about Read Product OCM » range 20 or 4-20 mA » resolution Specifications» 20 to 50 C -5 to 122 F IP65 enclosure » CE *, FM, CSA NRTL/C Programmer Temperature Sensor TransducerCabling Communication Software Auxiliary InputOutput » Belden Installation Installing the OCM-3Outline and Mounting OCM-3 Layout System Diagram OCM-3Customer device Installing the Temperature Sensor Installing the TransducerGround shield at OCM-3 only Basic Wiring Temperature Sensor Ground shield at OCM-3 only Relays MA Output Synchronization Power Connections AC PowerDC Power Installing the Programmer Installing the Memory BACK-UP BatteryDisconnect power before installing or replacing the battery Communicating VIA Computer Start UP GeneralKeypad OCM-3 is asking which language you prefer to communicate Initial Start UPLanguage English F13 auto zero calibration 160 Completed 7ML19985AB01 P0 language English P1 dimensional units Centimeters 24-hr. time 1141114100 Enter new time F5 ddmmyyyy date October 12 Fundamental Checks OCM Memory OperationSecurity Units Display Flow CalculationAbsolute vs. ratiometric = constant Damping For battery operation, set display lighting to off or auto Example For relay For battery operation, have relays energizing on alarm» 20 mA » P6 * flow rate FAIL-SAFE Flow Rate and TotalizingFlow rate Capacity Logging Viewing the data log Temperature BlankingTime and Date Reset Emulation Mode Auxiliary Head Input Flow Velocity InputVoltage Input Current Input As normal 7ML19985AB01 Diagnostic Aids DC Output100% head 4 m, enter 5 m ‘D’ Parameter Listing Security access requiredVelocity Nominal target range OCM Enter security code Emulation mode ‘F’ Parameter ListingKeypad to mA output OCM ‘P’ Parameter Listing Linear Velocity= centimetres = absolute = ratiometric Flow rate units Flowrate VolumeGallons = imperial million gallons per day OCM = 4-20 mA = 0-20 mA 7ML19985AB01 OCM OCM Fixed Variable conditionUnits OCM ‘U’ Parameters for P3 Primary Element OCM U0 = exponent U1 = k factor P4 = 0 only Reference= 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 = 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 mm 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 A15 Head, point A16 Flow, point A13 Head, point A14Flow, point A17 Head, point A18 Flow, point A19 U0 = channel width B U1 = area h Rectangular Area X Velocity = head, cm = flow velocity, cm/sec Trapezoidal Area X Velocity = B b/d Where q = flow rate, l/s For h ≥ d= 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 = Universal Area X Velocity Area HeadA10 = OCM Maintenance Error Codes Customer’s ComputerSerial printer 102 Protocol for the OCM-3 is as follows Baud rate DB-25 connector DB-9 connectorBipolar Current Refer to Cvcc Instruction Date P35 = 7, print interval set for 7 minutes104 Utilities Software Programmer Remote OCM-3 programming Remote OCM-3 display Local display105 106 Display value Typical OCM-300.000000 99.12399.123000 7ML19985AB01 107 Response # = 0 through Content of P5 Start data log down load Stop data log down load109 Standard modem DB-25 connector 7ML19985AB01Cable Computer Telephone lines Remote modem Establishing Communication Connect111 112 Ending Communication Rev