Siemens Typical OCM-3, Display value, 00.000000 99.12399.123000 7ML19985AB01, 107

Page 106

Custom Programming and Third Party Communication Program

Users who wish to write their own software to communicate with the OCM-3 are urged to implement a fully buffered (interrupt driven) serial link incorporating XON/XOFF.

Some users however, will not have the capacity for such an undertaking. Those users may still communicate with the OCM-3 using the less sophisticated communication capabilities provided by such high level languages as Basic, Pascal or C. The only restriction imposed by using a system that does not use XON/XOFF, is that the user must insure that he does not send long streams of commands to the OCM-3 without pausing periodically to allow the OCM-3 time to process them.

Most users who wish to write their own software to communicate with the OCM-3 will do so for a specific purpose. An example would be to create a customized data log. For this, the user will want that only the numeric values be returned, and none of the descriptive information.

To achieve this, the OCM-3 provides a secondary command parser which is accessed when the OCM-3 receives a command enclosed by ‘/’. When the leading ‘/’ is detected by the primary parser, the OCM-3 diverts the message to the secondary parser. The secondary parser remains in control until it receives the trailing ‘/’.

If the trailing ‘/’ is not received within a few seconds, the secondary parser is aborted and control is reverted to the primary parser automatically.

The OCM-3 response message to a command to the secondary parser is a sequence of ASCII characters terminated by an ASCII carriage return (hex 0D) and an ASCII line feed (hex 0A). All system parameters and most other responses are floating point numbers with a maximum of 6 decimal places.

e.g.

typical OCM-3

response

 

display value

message

00.000000

99.12399.123000

7ML19985AB01

OCM III

107

Image 106
Contents Open channel Unit Repair and Excluded Liability Contact Smpi Technical Publications at the following addressTable of Contents General Keypad Initial Start Up Fundamental Checks Start UPOperation Maintenance Error Codes 100 Communications 101 7ML19985AB01 AppendicesOCM Short About thisIf 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 enclosureProgrammer » CE *, FM, CSA NRTL/CTransducer 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 Basic Wiring Temperature Sensor Installing the TransducerInstalling the Temperature Sensor Ground shield at OCM-3 onlyMA Output RelaysSynchronization AC Power Power ConnectionsDC Power Disconnect power before installing or replacing the battery Installing the Memory BACK-UP BatteryInstalling the Programmer Communicating VIA ComputerGeneral Start UPKeypad Language Initial Start UPOCM-3 is asking which language you prefer to communicate EnglishP0 language English P1 dimensional units Centimeters F13 auto zero calibration 160 Completed 7ML19985AB01114100 Enter new time 114124-hr. time F5 ddmmyyyy date October 12Fundamental Checks OCM Security OperationMemory UnitsAbsolute vs. ratiometric Flow CalculationDisplay = constantFor battery operation, set display lighting to off or auto Damping» 20 mA For battery operation, have relays energizing on alarmExample For relay » P6 * flow rateFlow Rate and Totalizing FAIL-SAFEFlow rate Logging CapacityViewing the data log Blanking TemperatureTime and Date Emulation Mode ResetVoltage Input Current Input Flow Velocity InputAuxiliary Head Input As normal 7ML19985AB01DC Output Diagnostic Aids100% head 4 m, enter 5 m Velocity Security access required‘D’ Parameter Listing Nominal target rangeOCM ‘F’ Parameter Listing Enter security code Emulation modeKeypad to mA output OCM Linear Velocity ‘P’ Parameter Listing= centimetres Gallons Flowrate Volume= absolute = ratiometric Flow rate units = imperial million gallons per dayOCM = 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 SHARP-CRESTED Weirs Typical Weir ProfilesKhafagi 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 7ML19985AB01BS-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 CBS-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 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 Based on the Manning Formula = hydraulic radius = slope of hydraulic gradientRound 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 toFlow, point A17 Head, point A18 Flow, point A13 Head, point A14Flow, point A15 Head, point A16 Flow, point A19U0 = 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 Universal Area X VELOCITY, P3 = Typical open channelArea Head Universal Area X VelocityA10 = OCM Maintenance Error Codes Computer Customer’sSerial printer Protocol for the OCM-3 is as follows Baud rate 102Bipolar Current DB-9 connectorDB-25 connector Refer to Cvcc InstructionP35 = 7, print interval set for 7 minutes Date104 Remote OCM-3 display Local display Utilities Software Programmer Remote OCM-3 programming105 106 00.000000 99.12399.123000 7ML19985AB01 Typical OCM-3Display value 107# = 0 through Content of P5 ResponseStop data log down load Start data log down load109 Cable DB-25 connector 7ML19985AB01Standard modem Computer Telephone lines Remote modemConnect Establishing Communication111 Ending Communication 112Rev