Instruction Manual November 2005 open channel OCM III
Safety Guidelines: Warning notices must be observed to ensure personal safety as well as that of others, and to protect the product and the connected equipment. These warning notices are accompanied by a clarification of the level of caution to be observed. Qualified Personnel: This device/system may only be set up and operated in conjunction with this manual. Qualified personnel are only authorized to install and operate this equipment in accordance with established safety practices and standards.
TABLE OF CONTENTS TITLE PAGE ABOUT THIS ...
START UP General 21 Keypad 21 Legend 22 Initial Start Up 22 Fundamental Checks 25 OPERATION Memory 27 Security 27 Units 27 Flow Calculation 28 Display 28 Damping 29 Relays 30 mA Output 30 Fail-Safe 31 Flow rate and Totalizing 31 Logging 32 Blanking 34 Temperature 34 Time and Date 34 Emulation Mode 35 Reset 35 Flow Velocity Input 36 Auxiliary Head Input 36 DC Output 37 Diagnostic Aids 37 7ML19985AB01 OCM III 4
‘D’ PARAMETER LISTING 39 ‘F’ PARAMETER LISTING 41 ‘P’ PARAMETER LISTING 43 ‘U’ PARAMETERS FOR P3 PRIMARY ELEMENT 51 Simple Exponential Devices, P3 = 0 53 BS-3680 Rectangular Flume, P3 = 1 58 BS-3680 Round Nose Horizontal Crest Weir, P3 = 2 60 BS-3680 Trapezoidal Flume, P3 = 3 62 BS-3680 U - Flume, P3 = 4 64 BS-3680 Finite Crest Weir, P3 = 5 66 BS-3680 Thin Plate Rectangular Weir, P3 = 6 68 BS-3680 Thin Plate V-Notch Weir, P3 = 7 70 Rectangular Weir (Contracted), P3 = 8 72 Round Pip
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ABOUT THIS ... ABOUT THIS MANUAL Although the OCM-3 is very ‘approachable’ due its dialogue capabilities and intuitive operation, the user should be familiar with this manual. This manual provides the user with the necessary information required to install, start up and operate the OCM-3. As the OCM-3 prompts the user with specific messages in a step-by-step fashion during programming, the Start Up section serves essentially to compliment the OCM-3.
The OCM-3 converts the head measurement into flow rate, but also provides a velocity sensor input for applications where a flow velocity measurement is required to perform the flow calculation. The flow rate is totalized and stored in a comprehensive data log to provide detailed flow analysis. Programming of the OCM-3 allows the operator to select the flow calculation specific to the primary measuring device (flume, weir or pipe).
SPECIFICATIONS Power: » dc supply: » 9 to 30 V DC, 8 W max and / or » ac supply: » 100/115/200/230 V ac ± 15%, 50/60 Hz, 20 VA max Environmental: Memory back-up: » location » indoor /outdoor » altitude: » 2000 m max » ambient temperature » – 20 to 50 °C (–5 to 122 °F) » relative humidity » suitable for outdoor (Type 4X/Nema 4X IP65 enclosure) » installation category » II » pollution degree »4 » 3 V lithium battery (NEDA 5003LC or equivalent) » operating life 1 year » ‘SuperCap’ capacitor
» isolation: » relays: 300 V ac continuous » 3 alarm/control relays » 1 form ’C’ SPDT contact per relay, rated at 5 A at 250 V ac non-inductive or 30 V dc » dc output: » +24 V dc » 20 mA average to 200 mA at 1/10 duty cycle max Communication: » RS-232 or ± 20 mA bipolar current loop,300, 600, 1200, 2400, 4800, 9600 or 19200 baud Data Logs: » variable rate on 1, 5, 15, 30 or 60 min or 24 hr » 31 days minimum/2 years maximum Display: » illuminated liquid crystal 5 x 7 dot matrix display with 2 lines o
Battery: » 9 V (ANSI / NEDA 1604, PP3 or equivalent) or 3V lithium battery TRANSDUCER Model: » XRS-5* Refer to associated Transducer manual. TEMPERATURE SENSOR Model: » TS-2, LTS-1 or LTS-1C Refer to associated Temperature Sensor manual.
Auxiliary Input: » Belden 8760 or equivalent 24 V Output: » Belden 8760 COMMUNICATION SOFTWARE Milltronics Utilities Software on standard PC floppy disk for DOS 3.1 and up.
INSTALLATION Installation shall only be performed by qualified personnel and in accordance with local governing regulations. INSTALLING THE OCM-3 The OCM-3 should be mounted in a clean, dry area that is: within the ambient temperature range and suitable for the specified enclosure. The front cover should be accessible for programming and viewing. It is advisable to keep the OCM-3 away from high voltage or current runs, contactors and SCR control drives.
OCM-3 LAYOUT board A display board board B All field wiring must have insulation suitable for at least 250 V. Hazardous voltage present on transducer terminals during operation. dc terminals shall be supplied from SELV source in accordance with IEC 1010-1 Annex H. Relay contact terminals are for use with equipment having no accessible live parts and wiring having insulation suitable for at least 250 V. The maximum allowable working voltage between adjacent relay contacts shall be 250 V.
SYSTEM DIAGRAM Milltronics transducer, see Specifications OCM-3 Milltronics TS-2, temperature sensor mA output relay output auxiliary input velocity input RS-232 customer device customer alarm, pump or control device customer device customer device customer device bi-polar current (Milltronics communication) Milltronics CVCC Maximum system capability. Not all components or their maximum quantity may be required.
INSTALLING THE TRANSDUCER Max cable run 183 m (600 ft) of RG-62U or equivalent. Cable must be run in a grounded metal conduit with no other cabling (except Temp. Sensor cable). Ground shield at OCM-3 only. Insulate shield at junctions to prevent inadvertent grounding. Basic Wiring – Transducer Hazardous voltage present on transducer terminals during operation. Note: When using the XRS-5 transducer with the OCM-3, use the TS-2 external temperature sensor.
mA OUTPUT isolated 0 or 4 to 20 mA output (P26) into 1 KΩ load maximum. Wiring should conform to standard instrumentation practices. Ground shield at OCM-3 only. RELAYS relays shown in de-energized state, contacts rated at 5 A at 250 V non-inductive. n.c. com n.o. n.c. com n.o. n.c. com n.o. All relays are certified for use in equipment where the short circuit capacity of the circuits in which they are connected is limited by fuses having ratings not exceeding the rating of the relays.
SYNCHRONIZATION Where two to a maximum of twelve transducers will be sharing a common conduit the OCM-3s should be synchronized. In order to synchronize OCM-3s: » remove jumper J1 on board A on all but one OCM-3 » interconnect the SYNC terminal (TB1-20) of all OCM-3s. Insure that all OCM-3s share a common ground (TB1-34).
POWER CONNECTIONS The OCM-3 power supply accepts 100, 115, 200 or 230 V ac per switch SW1 (board B) selection and 9 to 30 V dc. The OCM-3 operates either under ac or dc power, or both ac and dc live simultaneously. If both ac and dc power are live, the OCM-3 normally draws power from the ac supply. In the event that the ac supply fails, the OCM-3 then draws power from the dc supply. AC POWER * * switch shown in ‘OFF’ position, select appropriate voltage.
INSTALLING THE MEMORY BACK-UP BATTERY Disconnect power before installing or replacing the battery. Do not install the memory back-up battery until the OCM-3 is to be used. The unit is supplied with one battery package. Remove the battery from the package and insert it into the battery socket. Refer to Operation \ Memory. The memory battery, B1 (see Specifications) should be replaced yearly to insure memory back up during lengthy power outages.
START UP GENERAL For the initial start up, it is advisable to use the programmer for programming the OCM-3. The programmer transmits a coded infrared signal each time a key is pressed. The OCM-3 is designed to automatically scroll through the ‘A’, ‘D’, ‘F’, ‘P’ and ‘U’ parameters in a structured sequence. The scrolling is interactive in that, depending on the option chosen for a given parameter, subsequent parameters may be skipped or modified.
LEGEND Press the associated programmer key: Display shown on OCM-3: Programmer key: INITIAL START UP After installation procedures have been completed, the OCM-3 may be powered up.
2 7 8 1 2 factory set security code 2.71828 must be entered 8 P0 0 language English P1 0 dimensional units centimeters if the wrong language was selected, it may be changed here continue programming by entering the desired options and advancing until the scroll returns to ‘P0’. It is then assumed that the user has entered all the required parameters. P0 0 language English For optimum calibration accuracy, an ‘F13’ should be performed prior to accessing ‘F2’, the normal operating mode.
If data logging is desired, the time and date must be set. 4 F4 24-hr. time e.g. 1141 1 1 4 1 F4 24-hr. time 1141 11: 41 a.m., seconds are always assumed to be 00 F4 24-hr. time 11:41:00 enter new time time is displayed in hh:mm:ss F5 (ddmmyyyy) date e.g. 12101492 1 2 1 October 12, 1492 0 1 4 9 2 F5 (ddmmyyyy) date 12/10/1492 enter new date The start up procedure is now complete. Enter ‘F2’ to place the OCM-3 in the normal operating mode.
FUNDAMENTAL CHECKS For accurate determination of flowrate, accurate head measurement is essential. Check the following and correct if necessary. » check D5 for correct temperature at transducer location. » check D9 for correct distance from transducer to head. » check D0 for accurate head measurement.
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OPERATION Upon power up, the transducer is fired periodically as set by P36. A long interval between measurements may be desirable in order to conserve power* when operating the OCM-3 from a DC source of limited capacity. The echo is processed to determine the head (D0). The flow rate (D1) is calculated by the OCM-3 as a mathematical function (P3 and P4) of head or a function of head and velocity (P42). The flow rate is then integrated to yield the totalized flow (D2).
FLOW CALCULATION Absolute vs. ratiometric The OCM-3 can be programmed to use either of two methods (P4) for calculating flow from the head measurement: absolute or ratiometric. The result is the same regardless of the method used. The principal difference is the information that must be entered in order for the OCM-3 to carry out the calculation. The user’s choice of method may ultimately be based upon the information which is at hand.
Flow Rate Field units, P5 flow rate Totalizer Field multiplier, P32 total Relay / No Echo Field relay identification under loss of echo condition, "NO ECHO" will alternately flash Status Field relay status : 0 = relay de-energized 1 = relay energized * = alarm state (indicated when flashing) The OCM-3 provides illumination for the LCD for easier viewing of the display. Illumination can be set (P14) to be normally on or off, or automatic.
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 .
The mA function can be overridden for test purposes by setting the desired mA value into F3. When the value is entered, the mA output will go to that value. When F3 is exited, the mA output will revert to normal operation. Also, see \ Emulation Mode. *In the case of absolute calculations (P4=0), P6 is calculated by the OCM-3. FAIL-SAFE In the event of an echo loss, the fail-safe timer will begin counting.
Under low flow conditions, a cut-off head (P45) can be entered to avoid totalizing flows occurring at or below the flow corresponding to the cut-off head. LOGGING The OCM-3 provides an extensive logging feature which can be viewed on the local display or retrieved via the serial communication link. The logging rate (P39) can be fixed or variable. The latter being useful in conserving logging space. The condition for variable logging is determined when selecting the logging rate.
Viewing the data log The day totalizer (F14) does not use the master totalizer multiplier (P32). It is possible that the daily total overflows. In such a case the display will show +++.++.
BLANKING Blanking is used to ignore the zone in front of the transducer where ringing or other false echo is at a level that interferes with the processing of the true echo. The minimum blanking is factory set, but can be overridden by entering the desired distance into P47. Ringing is the inherent nature of the transducer mass to continue vibrating after the transducer has been fired. Ringing decays to acceptable levels in the order of milliseconds.
The daily total will be increased proportional to the amount of time the day was lengthened. Adjusting the Date If the calendar is reset, the OCM-3 will adjust the log dates accordingly, taking into account leap years and days per month. EMULATION MODE The flow calculation (P3/P4) can be checked for accuracy by using the emulation parameter F1. The head is entered and the corresponding flow is displayed.
FLOW VELOCITY INPUT In some applications, the flow calculation for the chosen primary element requires a velocity input. In this type of application, the transducer measurement is used to calculate the cross sectional area of the flow. By multiplying the area with the distance per time units of velocity, the volume per time units of flow are calculated. The calculated velocity can be viewed via D8. The 0% and 100% limits of the velocity input must be scaled using parameters P8 and P9.
The 0% and 100% limits of the auxiliary input must be scaled using parameters P43 and P44. » select P43 » enter the voltage corresponding to zero head » select P44 » enter the head corresponding to 5 V. e.g. if the head output is 1 V per m and the output is scaled for 7 V at 100% head (7 m), then enter 5 m. If the output is scaled for 4 V at 100% head (4 m), enter 5 m. P43 and P44 can only be accessed if P42 has been set for head determination by an auxiliary device.
‘D’ PARAMETER LISTING Refer to ‘Operation’ for details.
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‘F’ PARAMETER LISTING Refer to ‘Operation’ for details.
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‘P’ PARAMETER LISTING Refer to ‘Operation’ for details.
13 = Rectangular Area x Velocity 14 = Trapezoidal Area x Velocity 15 = Modified Trapezoidal Area x Velocity 16 = U-channel Area x Velocity 17 = Circular Area x Velocity 18 = Gull-wing Area x Velocity 19 = Egg-shaped Area x Velocity 20 = Universal Area x Velocity P4 method of calculation 0 = absolute 1 = ratiometric P5 flow rate units flowrate volume 0 = litres per second 1 = cubic feet per second cubic feet 2 = imperial gallons per minute imperial gallons 3 = U.S. gallons per minute U.S.
P13 display damping 0 = off 1 = low 2 = med 3 = high P14 display lighting 0 = on 1 = auto off 2 = off P15 / P18 / P21 relay 1 / 2 / 3 assignment 0 = not in service 1 = de-energize on loss of echo 2 = energize on loss of echo 3 = de-energize on high flow rate 4 = energize on high flow rate 5 = de-energize on low flow rate 6 = energize on low flow rate 7 = de-energize on high head 8 = energize on high head 9 = de-energize on low head 10 = energize on low head 11 = de-energize on high velocity 12 = energi
24 = energize on low Aux. volts 25 = de-energize on high Aux. volts 26 = energize on high Aux.
P27 mA damping (secs) P28 mA options (emulator tracking) 0 = don’t track emulator 1 = track emulator P29 fail-safe time (secs) P30 fail-safe analog mode 0 = hold last value 1 = assume value in P31 P31 fail-safe analog mA (default value) P32 totalizer multiplier 0 = x 1/1000 (0.001) 1 = x 1/100 (0.01) 2 = x 1/ 10 (0.
P34 printer mode 0 = never print 1 = interval to be in minutes 2 = interval to be in hours 3 = print once each day P35 printer timing P36 measurement interval 0 = 1 sec 1 = 15 sec 2 = 30 sec 3 = 1 min 4 = 5 min P37 serial data rate 0 = 300 baud 1 = 600 2 = 1200 3 = 2400 4 = 4800 5 = 9600 6 = 19200 P38 site number 7ML19985AB01 OCM III 48
P39 data logging rate fixed 0 = 1 min 3 = 30 1=5 4 = 60 2 = 15 5 = 24 hr variable (condition) 6 = 15/1 min (% flow / min) 19 = 60 / 1 (flow) 7 = 15 / 5 " 20 = 60 / 5 " 8 = 30 / 1 " 21 = 24 hr / 1 min " 9 = 30 / 5 " 22 = 24 hr / 5 min " 10 = 60 / 1 " 23 = 24 hr / 15 min " 11 = 60 / 5 " 24 = 15 / 1 min (head) 12 = 24 hr / 1 min " 25 = 15 / 5 " 13 = 24 hr / 5 min " 26 = 30 / 1 " 14 = 24 hr / 15 min " 27 = 30 / 5 " (flow) 28 = 60 / 1 " 16 = 15 / 5 " 29 = 60 / 5 " 17 =
P42 head determination 0 = by OCM-3 1 = by auxiliary device P43 volts in for zero head P44 head at 5 volts in P45 low flow cut-off head P46 range at zero head P47 blanking distance 7ML19985AB01 OCM III 50
‘U’ PARAMETERS FOR P3 PRIMARY ELEMENT The number of ‘U’ parameters required varies according to the primary element chosen (P3) and the method of calculation (P4). The OCM-3 prompts the user by displaying the next required parameter, insuring the programming is complete. The following is a list of the specific primary elements to which the OCM-3 can be applied. Refer to the page covering your particular application; the rest may be disregarded. P3 primary element 0 exponential device (e.g.
17 Circular Area x Velocity 18 Gull Wing Area x Velocity 19 Egg-shaped Area x Velocity 20 Universal Area x Velocity The primary element must be installed in accordance with the manufacturers recommendations and in accordance with all governing regulations.
SIMPLE EXPONENTIAL DEVICES, P3 = 0 ‘U’ parameters required * U0 = exponent U1 = k factor (P4 = 0 only) Typical Exponential Devices: » Sutro (proportional) weir » head measurement only » Rectangular (suppressed) or Trapezoidal (Cipolletti) weir » Kahfagi venturi » Parshall flume » Leopold Lagco » Triangular (V-notch) weir * obtain from manufacturer’s specifications.
SIMPLE EXPONENTIAL DEVICES, P3 = 0 TYPICAL SHARP-CRESTED WEIRS transducer * minimum 3 x h max Typical Weir Profiles V - notch or Triangular U 0 = 2.5 Rectangular - suppressed U 0 = 1.5 Trapezoidal (Cipolletti) U 0 = 1.5 Sutro (Proportional) U0=1 (symmetrical or asymmetrical) For rated flows under free flow conditions, the head is measured upstream of the weir plate at a minimum distance of 3 times the maximum head (i.e. where the liquid surface is not affected by drawdown).
SIMPLE EXPONENTIAL DEVICES, P3 = 0 KHAFAGI VENTURI 15 cm (6") plan transducer * 0 head side front For rated flows under free flow conditions, the head is measured 15 cm (6") upstream from the beginning of the converging section. * The transducer must be above the maximum head by at least the blanking value, P47.
SIMPLE EXPONENTIAL DEVICES, P3 = 0 TYPICAL PARSHALL FLUME C 2/3 C plan transducer * 0 head side front For rated flows under free flow conditions, the head is measured at 2/3 the length of the converging section upstream of the beginning of the throat section. * The transducer must be above the maximum head by at least the blanking value, P47.
SIMPLE EXPONENTIAL DEVICES, P3 = 0 TYPICAL LEOPOLD LAGCO throat Q converging plan diverging transducer * point of measurement 0 head front side For rated flows under free flow conditions, the head is measured at a point upstream referenced to the beginning of the converging section. Refer to the following table. Flume Size Point of Measurement (pipe dia. in inches) mm 4 - 12 25 inches 1.0 15 32 1.3 18 38 1.5 21 44 1.8 24 51 2.1 30 64 2.5 36 76 3.0 42 89 3.5 48 102 4.
BS-3680 Rectangular Flume, P3 = 1 ‘U’ parameters required * ‘U’ parameters calculated ** U0 = approach width U1 = throat width B b U4 = Cv U5 = Cd U2 = hump height U3 = throat length p L U6 = A *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 Cv x Cs x Cd x B x h1.
BS-3680 RECTANGULAR FLUME 3 to 4 x hmax L transducer * 0 head h p * The transducer must be above the maximum head by at least the blanking value, P47.
BS-3680 Round Nose Horizontal Crest Weir, P3 = 2 ‘U’ parameters required * ‘U’ parameters calculated ** U0 = crest width b U3 = Cv U1 = crest height p U4 = Cd U2 = crest length L U5 = A * 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 Cv x Cs x Cd x b x h1.
BS-3680 ROUND NOSE HORIZONTAL CREST WEIR transducer * 3 to 4 x hmax * The transducer must be above the maximum head by at least the blanking value, P47.
BS-3680 TRAPEZOIDAL FLUME, P3 = 3 ‘U’ parameters required * ‘U’ parameters calculated ** U0 = approach width B U5 = Cv U1 = throat width b U6 = Cd U2 = hump height p U7 = Cs U3 = throat length L U8 = A U4 = slope m *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 Cv x Cs x Cd x b x h1.
BS-3680 TRAPEZOIDAL FLUME b p end B transducer * plan 3 to 4 x hmax L h side p * The transducer must be above the maximum head by at least the blanking value, P47.
BS-3680 U-Flume, P3 = 4 ‘U’ parameters required * ‘U’ parameters calculated ** U0 = approach diameter Da U4 = Cv U1 = throat diameter D U5 = Cd U2 = hump height p U6 = Cu U3 = throat length L U7 = A * 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 Cv x Cu x Cd x D x h1.
BS-3680 U-FLUME 3 to 4 x hmax L D Da transducer * 0 head h p * The transducer must be above the maximum head by at least the blanking value, P47.
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.
BS-3680 FINITE CREST WEIR transducer * 3 to 4 x hmax * The transducer must be above the maximum head by at least the blanking value, P47.
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.
BS-3680 THIN PLATE RECTANGULAR WEIR transducer * 4 to 5 x hmax * The transducer must be above the maximum head by at least the blanking value, P47.
BS-3680 THIN PLATE V-NOTCH WEIR, P3 = 7 ‘U’ parameters required * U0 = notch angle ‘U’ parameters calculated ** 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.
BS-3680 THIN PLATE V-NOTCH WEIR transducer * 4 to 5 x hmax * The transducer must be above the maximum head by at least the blanking value, P47.
RECTANGULAR WEIR (CONTRACTED), P3 = 8 ‘U’ parameters required * U0 = crest width b * 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 = K x (b - 0.2h) x h1.5 where : q = flow rate h = head K = constant RATIOMETRIC CALCULATION, P4 = 1¤ For flows that can be calculated by the equation: q = qcal x (b - 0.2h)/(b - 0.2hcal) x (h/hcal)2.
RECTANGULAR WEIR - CONTRACTED transducer * 4 to 5 x hmax * The transducer must be above the maximum head by at least the blanking value, P47.
ROUND PIPE, P3 = 9 (based on the Manning Formula) ‘U’ parameters required * U0 = pipe inside diameter D U1 = slope (fall/run) s U2 = roughness coefficientn *obtain from manufacturer’s specifications. Reference ABSOLUTE CALCULATION, P4 = 0¤ For flows that can be calculated by the equation: q = K/n x f(h) x s0.5 where : q = flow rate h = head K = constant f(h) = A x R0.
ROUND PIPE transducer * ** h * This dimension should be at least 15 cm (6") shorter than the blanking value, P47. ** The transducer must be above the maximum head by at least the blanking value, P47.
PALMER-BOWLUS FLUME *, P3 = 10 ‘U’ parameters required ** U0 = maximum flume width, hmax * typically those manufactured by Warminster or Plasti-Fab. ** obtain from manufacturer’s specifications. Reference RATIOMETRIC CALCULATION, P4 = 1¤ For flows that can be calculated by the equation: q = qcal x f(h/hmax) / f(hcal/hmax) where : ¤ q = flow rate qcal = flow rate at maximum head h = head hcal = maximum head f(h/hmax) is determined by polynomial synthesis Refer to Operation \ Flow Calculation.
PALMER-BOWLUS FLUME transducer ** D / 2, point of measurement * 0 head D = pipe or sewer diameter * for rated flows under free flow conditions ** The transducer must be above the maximum head by at least the blanking value, P47.
H-FLUME *, P3 = 11 ‘U’ parameters required * U0 = maximum listed head, hmax * as developed by the U.S. Department of Agriculture, Soil Conservation Service. ** obtain from manufacturer’s specifications. Reference RATIOMETRIC CALCULATION, P4 = 1¤ For flows that can be calculated by the equation: q = qcal x f(h/hmax)/f(hcal/hmax) where : ¤ q = flow rate qcal = flow rate at maximum head f(h/hmax) and f(hcal/hmax) are determined by polynomial synthesis Refer to Operation \ Flow Calculation.
H-FLUME transducer * point of measurement plan front side For rated flows under free flow conditions, the head is measured at a point downstream from the flume entrance. Refer to the following table. Flume Size Point of Measurement D (feet) cm inches 0.5 4.7 1.88 0.75 6.7 2.69 1.0 9.1 3.63 1.5 13.5 5.38 2.0 17.9 7.19 2.5 22.5 9.00 3.0 27.2 10.88 4.5 40.5 16.19 * The transducer must be above the maximum head by at least the blanking value, P47.
UNIVERSAL HEAD vs FLOW, P3 = 12 The flow curve is characterized by entering the head (Aeven) and flow (Aodd) ordinates for the number of data points (n, 4 to 16) over the flow range. The first point (A0,A1) generally being at 0 head and the last point (A2n-2,A2n-1) generally being at maximum head . ‘U’ parameters required * U0 = number of data points (n, 4 to 16) Aeven = head Aodd = flow rate * obtain from manufacturer’s specifications.
UNIVERSAL HEAD vs FLOW e.g. typical compound weir Parameters U0 = 11 A0 = 0 A1 = 0 head, point 1 flow, point 1 A12 = 1.05 A13 = 2.65 head, point 7 flow, point 7 A2 = 0.3 A3 = 0.1 head, point 2 flow, point 2 A14 = 1.2 A15 = 3.4 head, point 8 flow, point 8 A4 = 0.6 A5 = 0.7 head, point 3 flow, point 3 A16 = 1.4 A17 = 5.0 head, point 9 flow, point 9 A6 = 0.8 A7 = 1.5 head, point 4 flow, point 4 A18 = 1.7 A19 = 8.0 head, point 10 flow, point 10 A8 = 0.95 A9 = 2.
RECTANGULAR AREA X VELOCITY, P3 = 13 ‘U’ parameters required * ‘U’ parameters calculated ** U0 = channel width B U1 = area (h) *obtain from manufacturer’s specifications. ** calculated by OCM-3. May be viewed by accessing ‘U’ parameter.
RECTANGULAR AREA X VELOCITY transducer * * The transducer must be above the maximum head by at least the blanking value, P47.
TRAPEZOIDAL AREA X VELOCITY, P3 = 14 ‘U’ parameters required * U0 = channel top width B U1 = channel base width b U2 = channel depth ht ‘U’ parameters calculated ** U3 = area (h) * obtain from manufacturer’s specifications. ** calculated by OCM-3. May be viewed by accessing ‘U’ parameter.
TRAPEZOIDAL AREA X VELOCITY transducer * * The transducer must be above the maximum head by at least the blanking value, P47.
MODIFIED TRAPEZOIDAL AREA X VELOCITY, P3 = 15 ‘U’ parameters listed * ‘U’ parameters calculated ** U0 = channel top width B U1 = channel base width b U2 = transition height ht U3 = area (h) *obtain from manufacturer’s specifications. ** calculated by OCM-3. May be viewed by accessing ‘U’ parameter.
MODIFIED TRAPEZOIDAL AREA X VELOCITY transducer * * The transducer must be above the maximum head by at least the blanking value, P47.
U-CHANNEL AREA X VELOCITY, P3 = 16 ‘U’ parameters required * ‘U’ parameters calculated ** U0 = base diameter D U1 = area (h) * obtain from manufacturer’s specifications. ** calculated by OCM-3. May be viewed by accessing ‘U’ parameter.
U-CHANNEL AREA x VELOCITY transducer * * The transducer must be above the maximum head by at least the blanking value, P47.
CIRCULAR AREA X VELOCITY, P3 = 17 ‘U’ parameters listed * U0 = conduit diameter ‘U’ parameters calculated ** ID U1 = area (h) * obtain from manufacturer’s specifications. ** calculated by OCM-3. May be viewed by accessing ‘U’ parameter.
CIRCULAR AREA X VELOCITY transducer * ** h * This dimension should be at least 15 cm (6") shorter than the blanking value, P47. ** The transducer must be above the maximum head by at least the blanking value, P47.
GULL-WING AREA X VELOCITY, P3 = 18 ‘U’ parameters required * ‘U’ parameters calculated ** U0 = channel base width b U4 = area (h) U1 = lower angle alpha (α) U2 = upper angle beta (β) U3 = transition height ht * obtain from manufacturer’s specifications. ** calculated by OCM-3. May be viewed by accessing ‘U’ parameter.
GULL WING AREA X VELOCITY transducer * V * The transducer must be above the maximum head by at least the blanking value, P47.
EGG-SHAPED AREA X VELOCITY, P3 = 19 ‘U’ parameters listed * ‘U’ parameters calculated ** U0 = top radius R U1 = bottom radius r U2 = axial displacement d U3 = area (h) * obtain from manufacturer’s specifications. ** calculated by OCM-3. May be viewed by accessing ‘U’ parameter.
EGG-SHAPED AREA X VELOCITY transducer * standpipe ** * This dimension should be at least 15 cm (6") shorter than the blanking value, P47. ** The transducer must be above the maximum head by at least the blanking value, P47.
UNIVERSAL AREA X VELOCITY, P3 = 20 Arbitrary area is typically used when the primary element and/or its flow do not fit any of the primary elements covered by P3. There is no user difference between absolute and ratiometric calculations P4. The flow curve is characterized by entering the head (Aeven) and area (Aodd) ordinates for the number of data points (n, 4 to 16) over the flow range. The first point (A0,A1) generally being at 0 head and the last point (A2n-2,A2n-1) generally being at maximum head .
UNIVERSAL AREA X VELOCITY A odd Area Head U0 = 8 A0 = 0 A1 = 0.0 A even head, point 1 area, point 1 A2 = 0.05 A3 = 0.03 head, point 2 area, point 2 A4 = 0.1 A5 = 0.06 head, point 3 area, point 3 A6 = 0.15 A7 = 0.09 head, point 4 area, point 4 A8 = 0.25 A9 = 0.18 head, point 5 area, point 5 A10 = 0.45 head, point 6 A11 = 0.35 area, point 6 A8 = 0.70 A9 = 0.59 head, point 7 area, point 7 A8 = 1.00 A9 = 0.
7ML19985AB01 OCM III 98
MAINTENANCE The OCM-3 requires very little maintenance due to its solid-state circuitry. However, a program of periodic preventative maintenance should be initiated. This should include regular inspection, general cleaning, overall system performance checks and standard good housekeeping practices. A periodic inspection of the transducer is recommended, at which time any build-up of material on the face should be removed. The enclosure should be cleaned using a vacuum cleaner and a clean, dry brush.
ERROR CODES Error Code Listing 1 number underflow 2 number overflow 3 divide error 4 bad argument 5 invalid parameter 6 system is locked 7 head exceeds BS-3680 spec 8 must use ratiometric 9 invalid angle size 10 invalid selection 11 value is view-only 12 characterizer in use 13 feature not available 14 need whole number 15 invalid date 16 invalid time 20 can’t zero auxiliary device 21 b must be greater than R-r 7ML19985AB01 OCM III 100
COMMUNICATIONS The OCM-3 provides serial communication either through Milltronics proprietary bipolar current loop or industry standard RS-232. Communication can be used to provide a video or paper printout of OCM activity. It can also be used to provide remote programming and retrieval of the data log, from devices such as computers and PLCs. When using the bipolar current loop, communication runs of up to 1,500 m can be achieved, as opposed to the limited runs of 15 m using RS-232.
Milltronics provides a standard Utilities software package, for convenient communication between an IBM PC compatible computer and the OCM-3. In addition, the user may opt to develop his own custom software program to perform tasks suited to his specific needs. Protocol The protocol for the OCM-3 is as follows: baud rate: set via P37 parity: none stop bits: 1 word length: 8 The OCM-3 uses a three wire XON/XOFF serial communication link.
Interconnection Bipolar Current BIPOLAR I/O CURRENT O/P S H L D refer to CVCC instruction manual for connection to computer + - R R X X + - S H L D T X T X + - T X D OCM-3 TB1 1 2 3 4 5 6 7 8 9 10 11 CVCC TB1 1 2 3 4 5 6 7 - + T R A N S M I T - + S H E I L D C O M M O N R E C E I V E RS-232 IBM PC Computer Connection computer serial port DB-9 connector 7ML19985AB01 computer serial port DB-25 connector OCM III 103
Timed Print Out The OCM-3 can be programmed to periodically print out OCM data (P34/35). A typical print out will have the following format. Time hh:mm:ss Date dd/mm/yy Site Number # Head # units * Velocity # units Temperature # units Flow Rate # units Flow Total # units * only for applications using velocity input When the output is directed to a serial printer, a delay is inserted between each line to allow the printer time to print each line before another is sent.
Milltronics Utilities Software Disk The Milltronics Utilities Software expands the human interface capabilities of the OCM-3 as compared to that provided by the simple use of the infra-red programmer.
The OCM-3 Utilities software provided by Milltronics uses XON/XOFF to ensure communication reliability. The software is written to be executed on an IBM PC compatible computer. The standard keyboard emulates the OCM-3 programmer. Pressing the keys corresponding to those displayed on the programmer will activate the same function (see Start Up\Keypad). In addition, special functions are provided using the ’w’ and ’v’ keys found on keyboard. For additional information, refer to the ’README.
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 following is a list of commands for the secondary parser: Command /a#/ Response the content of a#, where: a = A, D*, F, P and U # = 0 through 9 e.g. * /P5/ the content of P5 D parameters are the only parameters which may be altered through the secondary command parser (which bypasses the security parameter F0). This may be useful, for example, in periodically reading and then resetting the short total, ‘D2’.
/j/ returns a code indicating the relay status code relay 1 2 3 0 0 0 0 1 1 0 0 2 0 1 0 3 1 1 0 4 0 0 1 5 1 0 1 6 0 1 1 7 1 1 1 /l/ start data log down load. /l1.dd.mm.yyyy/ data log down load - start date /l2.dd.mm.
Modem Communication Communication with the OCM-3 over an answer back telephone modem is relatively straight forward. For modem communication over conventional telephone lines, a maximum of 1200 or 2400 baud is recommended. Generally, a lower baud rate is more reliable on noisy lines. Modem should be self answering and data checking capability turn on. The Milltronics Utilities software can be run via modem.
Considerations - set the ’cold start’ (F12) default baud to 1200 by removing jumper J1 on board A. - set both modems and the OCM-3 baud rates to 1200. - set the remote modem to operate in the ’answer back’ mode. Refer to modem’s user manual. Communication - select serial programming link with OCM-3, from the utilities menu. See Milltronics Utilities Software Disk. The computer screen will display the letters ’v’.
Ending Communication - type W to break OCM-3 communication with the modem*. The computer screen will display a flashing message ‘OCM-3 muted’. - type: +++ (not displayed on the screen) and then press ENTER This will cause both modems to switch to the ‘command’ mode. The local modem sends a message to the screen (typical). OK - type: ATH and press the ENTER key. Both modems will hang up. The local modem sends a message to the screen (typical).
www.siemens.com/processautomation Siemens Milltronics Process Instruments Inc. 1954Technology Drive, P.O. Box 4225 Peterborough, ON, Canada K9J 7B1 Tel: (705) 745-2431 Fax: (705) 741-0466 Email: techpubs.smpi@siemens.com Siemens Milltronics Process Instruments Inc. 2005 Subject to change without prior notice *7ml19985AB01* Printed in Canada Rev. 1.
