Example For relay, » 20 mA, » P6 * flow rate | Siemens 7ML19985AB01

RELAYS

Three on board multipurpose relays are provided by the OCM-3. P15, 18 and 21 set the respective functions for relays 1, 2 and 3. Depending on the function selected, these parameters determine the need and configuration of the subsequent relay control parameters, P16, 17 (relay 1); P19, 20 (relay 2) and P22, 23 (relay 3).

If the relay is to function as a driver for a remote totalizer or as a flow sampler contact, the totalizer multiplier (P32) will be factored by the setpoint . Note that parameters P16, P19, and P22 will default to zero. When a relay is set to totalizer (P32), you must have the applicable parameter (P16 for relay 1, P19 for relay 2, or P22 for relay 3) set to something other than zero (normally 1).

Example: For relay 1

Relay totalizer factor = totalizer factor (P32) relay 1 setpoint (P16)

=100 (P32=5)

2 (P16)

=50 units/pulse

The status of each relay is shown in the display. Refer to \ Flow and Total Display.

For battery operation, have relays energizing on alarm.

mA OUTPUT

The OCM-3 provides a mA output (TB1-4/5) which can be assigned (P24) to represent the measurement of flow, head, velocity or temperature. The associated scaling, P25, is factory set to a value of ‘0’. This provides normal scaling with respect to the assigned measurement.

Normal scaling for representation of flow, head or velocity is:

» 0 or 4 mA	= 0
» 20 mA	= maximum measurement value for:	» P6*: flow rate
		at maximum head
		» P7: maximum head
		» P10: velocity
		at maximum head

Normal scaling for representation of temperature is:

» 0 or 4 mA = – 40 °C

» 20 mA = 60 °C

If custom scaling is required, the 20 mA corresponding value (other than 0) can be entered into P25. The range (0 to 20 or 4 to 20 mA) and damping (see Damping) are set via P26 and P27 respectively.

7ML19985AB01

OCM III

30

Image 30

Siemens 7ML19985AB01 Example For relay, For battery operation, have relays energizing on alarm, » 20 mA, » P6 * flow rate

Contents

Open channel Unit Repair and Excluded Liability Contact Smpi Technical Publications at the following address Table of Contents Start UP General Keypad Initial Start Up Fundamental ChecksOperation Maintenance Error Codes 100 Communications 101 7ML19985AB01 Appendices OCM About this ShortIf you want to know about Read Product OCM » 20 to 50 C -5 to 122 F Specifications» range 20 or 4-20 mA » resolution IP65 enclosure Programmer » CE *, FM, CSA NRTL/C Temperature Sensor TransducerCabling Communication Software Auxiliary InputOutput » Belden Installation Installing the OCM-3Outline and Mounting OCM-3 Layout System Diagram OCM-3Customer device Ground shield at OCM-3 only Basic Wiring Temperature Sensor Installing the TransducerInstalling the Temperature Sensor Ground shield at OCM-3 only MA Output Relays Synchronization Power Connections AC PowerDC Power Disconnect power before installing or replacing the battery Installing the Memory BACK-UP BatteryInstalling the Programmer Communicating VIA Computer Start UP GeneralKeypad Language Initial Start UPOCM-3 is asking which language you prefer to communicate English P0 language English P1 dimensional units Centimeters F13 auto zero calibration 160 Completed 7ML19985AB01 114100 Enter new time 114124-hr. time F5 ddmmyyyy date October 12 Fundamental Checks OCM Security OperationMemory Units Absolute vs. ratiometric Flow CalculationDisplay = constant For battery operation, set display lighting to off or auto Damping » 20 mA For battery operation, have relays energizing on alarmExample For relay » P6 * flow rate FAIL-SAFE Flow Rate and TotalizingFlow rate Logging Capacity Viewing the data log Temperature BlankingTime and Date Emulation Mode Reset Voltage Input Current Input Flow Velocity InputAuxiliary Head Input As normal 7ML19985AB01 Diagnostic Aids DC Output100% head 4 m, enter 5 m Velocity Security access required‘D’ Parameter Listing Nominal target range OCM Enter security code Emulation mode ‘F’ Parameter ListingKeypad to mA output OCM ‘P’ Parameter Listing Linear Velocity= centimetres Gallons Flowrate Volume= absolute = ratiometric Flow rate units = 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 SHARP-CRESTED Weirs Typical Weir Profiles 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 Cv = velocity coefficient ¤ Refer to Operation \ Flow Calculation 7ML19985AB01 BS-3680 Trapezoidal Flume BS-3680 U-Flume, P3 = BS-3680 U-FLUME = crest width = C = crest height = Cp = crest length = head H and p applied to C BS-3680 Finite Crest Weir = gravitational acceleration = Ce x 2⁄3 ⎯⎯√2⎯g x be x he1.5 Where q = flow rate= approach width = Ce = crest width = K b = crest height = 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 Based on the Manning Formula = hydraulic radius = slope of hydraulic gradient Round Pipe U0 = maximum flume width, hmax PALMER-BOWLUS Flume U0 = maximum listed head, hmax Flume Universal Head vs FLOW, P3 = U0 = number of data points n, 4 to Flow, point A17 Head, point A18 Flow, point A13 Head, point A14Flow, point A15 Head, point A16 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 Universal Area X VELOCITY, P3 = Typical open channel Universal Area X Velocity Area HeadA10 = OCM Maintenance Error Codes Customer’s ComputerSerial printer Protocol for the OCM-3 is as follows Baud rate 102 Bipolar Current DB-9 connectorDB-25 connector 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 00.000000 99.12399.123000 7ML19985AB01 Typical OCM-3Display value 107 # = 0 through Content of P5 Response Start data log down load Stop data log down load109 Cable DB-25 connector 7ML19985AB01Standard modem Computer Telephone lines Remote modem Establishing Communication Connect111 Ending Communication 112 Rev