Milltronics OCM II PL-269 User manual
OCM II
PROCESS MEASUREMENTS
OPEN CHANNEL MONITOR
Instruction Manual
PL-269
February 1991
33452690
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equipment that is designed for reliability and ease of use.
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measurement in-line weighing of dry bulk solids and motion sensing.
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TABLE OF CONTENTS
SECTION TITLE PAGE
USERS GUIDE TO MANUAL iii
I GENERAL INFORMATION 1 - 1
II SPECIFICATIONS 2 - 1
III INSTALLATION
OCM II 3 - 1
Battery 3 - 1
Transducer 3 - 1
Temperature Sensor 3 - 2
Velocity Sensor 3 - 2
Interconnection 3 - 2
IV START UP
General 4 - 1
Keypad 4 - 2
Keypad Entry 4 - 3
Display 4 - 4
Initial Start up 4 - 4
P4 and F12 Auto Zero 4 - 6
Setting the Clock 4 - 7
Setting the Calendar 4 - 7
V DAILY OPERATION
Normal Operation, F2 5 - 1
Flowrate Log, F9 5 - 2
Daily Flow Total, F10 5 - 2
VI AUXILIARY OPERATIONS
F1 Emulation Mode 6 - 1
F3 Clearing Totalizers 6 - 1
F11 Clearing the Log Buffers 6 - 2
F13 Diagnostic routine 6 - 2
F14 Forced Cold Start 6 - 2
Re-calibration 6 - 3
VII TABLES
#1 "D", displays 7 - 1
#2 "F", functions 7 - 3
#3 "P", parameters 7 - 5
#4 "U", parameters 7 - 9
VIII MAINTENANCE 8 - 1
PL-269 10 – 1
IX APPENDICES
A ERROR CODES 9 - 1
B EXAMPLES
#1 Parshall Flume 9 - 2
#2 Rectangular Flume 9 - 3
#3 Velocity-Area Product 9 - 4
Universal Head vs Flow Calculation 9 - 6
Re-scaling Velocity Sensor Input 9 - 8
C SERIAL COMMUNICATIONS 9 - 9
D AUXILIARY PRINTER 9 - 12
E GLOSSARY 9 - 13
Calibration Flow Chart 9 - 15
F TROUBLESHOOTING 9 - 17
OCM II Test Report
X FIGURES
Listing 10 - 1
■
91/02/14
PL-269 ii
USERS GUIDE TO MANUAL
Although the OCM II may appear complex due to the diversity of applications it may be programmed for, it is in
fact quite simple in the confines of a particular application.
By adhering to the following suggestions, it will be found that the OCM II is quick and easy to calibrate.
STEP ONE
Sections I through V should be read in order that the user may be familiarized with the OCM II.
STEP TWO
Refer to Table 3 listing the "P" parameters. Establish the values or codes to be entered for the parameters
required. Write (pencil) these onto the calibration flow chart, or a photocopy, for each device you have and circle
the corresponding units or mode.
STEP THREE
Refer to Table 4 listing the "U" parameters. As there are many different types of flow applications, it will greatly
simplify matters for the user to select the one that fits his requirements and to disregard all others. Establish the
values or codes to be entered for the parameters required. Write these onto the calibration flow chart and
circle the corresponding units or mode.
STEP FOUR
Now that all the data required to perform the calibration has been copied onto the calibration flow chart, follow
the flow chart and enter your parameter values in order as prompted by the OCM II.
Should you require assistance in determining your application type, contact Milltronics or your distributor.
■
PL-269 iii
SECTION I
GENERAL INFORMATION
The Milltronics OCM II Open Channel Metering system is comprised of a NEMA 4 enclosed, microprocessor
based electronic package, ultrasonic transducer and solid state temperature sensor.
The OCM II system employs the principle of echo ranging to determine level. The OCM II transducer emits a
precisely defined burst of ultrasonic energy. The echo reflected from the liquid surface, delayed in time relative
to the distance travelled, is received by the transducer. This time interval, between transmitted pulse and received
echo, is electronically processed into a digital indication of the target level or head.
The OCM II monitors the head of any liquid which flows with free surface in natural or fabricated open channels,
as well as in partially or totally enclosed pipes.
Many open channels utilize specific weirs or flumes to restrict flow in a manner that permits the use of precise
flow calculation formulae. The OCM II was designed to permit the operator to enter information specific to the
application into the battery protected memory via the front panel keypad.
The OCM II derives the flowrate from the head measurement which is totalized and stored in a data log to provide
a detailed flow analysis. In some cases the use of a velocity sensor to determine the flow velocity may be required
to perform a flow calculation. The OCM II provides the excitation voltage required to operate such a device.
Special emphasis has been placed on providing the most accurate flow calculations possible. To that end, specific
routines have been written to comply with the British Standards Institute’s Specifications BS-3680. These routines
calculate correction factors that take into account second-order effects such as approach velocity and boundary
layer effects.
The OCM II Universal Flow Calculation features may be utilized where the flow is unrestricted or where the weir
or flume used is not otherwise specifically listed in Table 4 of this instruction manual.
The LCD display, analog mA output, relay contact closure, and serial communication data link provided, may be
programmed as desired, to provide local and/or remote access to a wide variety of detailed flow information.
■
PL-269 1 – 1
SECTION II
SPECIFICATIONS
Power - standard - 115/230 V ±10%, 25 VA, 50/60 Hz
- special - 100/200 V ±10%, 25 VA, 50/60 Hz
- optional - +24 V DC ±10%, 25 VA
Fuse - 1/4 amp MDL Slo-Blo or equivalent
Range - 0.6 to 3.0 M (2 to 10 ft)
Transducer - model ST-25B or C, OCM grade
- CPVC body with polyurethane face
- 1" NPT mounting / conduit connection
- totally encapsulated
- carries CSA, FM and BASEEFA approvals for
hazardous locations.
Operating - electronics - – 20 to 60 °C (– 5 to 140 °F)
Temperature
- transducer - – 40 to 93 °C (– 40 to 200 °F)
- optional - 115 V AC, 125 VA thermostatically controlled heater available,
where electronics operating temperature may fall below
– 20 °C (– 5 °F)
Outputs: - transducer - 600 V peak to peak pulses of 0.5 msec. duration every 90 msec.
drive
- anolog - 0-20 or 4-20mA DC isolated current output into 750 ohms
maximum; proportional to: head, flow or velocity
- relay - one relay * form C (SPDT) contact rated 5 A @ 220 V AC,
non-inductive to serve either alarm, totalizing or sampling functions
- optional Satellite Dual Alarm or Satellite Pump Module.
Refer to instruction manual PL-232.
Resolution - 0.2 mm
92/07/07
PL-269 2 –1
*The relay is certified for use in equipment where the short circuit capacity capability of the circuits in
which they are connected is limited by fuses having ratings not exceeding the rating of the relays.
Temperature - one temperature sensor input
Compensation
- error: - without temperature sensor: 0.17%/ °C
- with temperature sensor: 0.09%
- optional Temperature Sensor
Data logs - 45 days flowrate and daily total flow
Display - two LCD displays for entry and read-out
Data Link - data logs may be retrieved or reset via RS232C compatible link at one
of 4 baud rates: 9600, 2400, 1200 or 300.
- will output to a serial printer at regular intervals or on demand.
Temperature Sensor - model - TS-2
(optional)
- range - –40 to 70 °C (–40 to 158 °F)
- construction - PVC body
- totally encapsulated
- resistance - 9.53 KΩ(nominal) at 20 °C (68 °F) ±5 KΩtemperature variance
- separation - 183 m (600 ft) from OCM II under specified conditions.
Refer to cabling
- approvals - CSA, FM and BASEEFA
- shipping weight - 0.5 Kg (1lb)
Cabling (optional) - transducer - RG-62U coax
- max. distance to OCM II: 183 M (600 ft)
- must be run in grounded metal conduit
- temp. sensor - Belden 8760, 1 pair shielded / twisted, 18ga
- max. distance to OCM II: 183 M (600 ft)
- can be run in same conduit with transducer cable
- data link - Belden 9553, 3 pair shielded/twisted, 18ga
- cable length: min. possible, max. 5 M (50 ft.)
PL-269 2 –2
Battery - RAM back-up - 3 volt lithium, PC mount
- operating life: 1 year
- Duracell type DL-2025 Eveready, Sanyo or GE type CR-2025
Ray-O- Vac or Panasonic CR-2016.
Enclosure - Nema 4 thermoplastic with hinged clear polycarbonate door
Weight - transducer: - 0.9 Kg (2 lb)
- OCM II: - 6.8 Kg (15 lb)
- temp sensor: - 0.45 Kg (1 lb)
■
PL-269 2 –3
SECTION III
INSTALLATION
OCM II
The OCM II should be mounted in a clean dry area; within the operating temperature range and non-corrosive
to, the electronics and the NEMA 4 polycarbonate enclosure. The enclosure door should be accessible to allow
calibrating and viewing. Refer to Figure 1 for outline and mounting details.
Do not mount the OCM II in direct sunlight
without the use of a sun shield
BATTERY
After mounting the OCM II, open the cover and remove the front panel by loosening the captive thumb screws.
The unit is supplied with one battery package. Remove the battery from the package and insert it into either of
the two battery sockets. The second battery socket is for installing a new battery before removing the old one,
so as not to loose calibration and data logged into the memory.
Do not install the memory back-up battery until
the OCM II is to be powered and put into use.
A battery installed in a non-powered unit will be drained in about one year. Remove the battery during extended
shut down.
TRANSDUCER
Transducer wiring must be done in conjunction with approved conduit, boxes
and fittings and to procedures in accordance with all governing regulations.
All transducer wiring must be run in grounded metal conduit for optimum noise rejection. Ground shield only at
OCM II and insulate shield at junctions to prevent inadvertent grounding.
Refer to Figures 3 & 8 in the back of this manual for wiring information and Figure 5 for general
mounting practices.
1. Mount the transducer such that it is centered over the flow at a minimum height of 60 cm (2 ft) above the
highest liquid level with its radiating face aimed directly down. "U" parameter drawings depicting transducer
location are for reference only. Refer to the manufacturer of the primary measuring device for the specified
point of head measurement.
2. Position the transducer such that its sound path is perpendicular to the liquid surface. Noting that the
transducer beam angle is about 12° (6° off vertical or a rise:run of 10:1), care must be taken to position the
transducer such that the sound path to the liquid surface is unobstructed and does not intersect the walls of
the flume or weir.
91/02/14
PL-269 3 – 1
TEMPERATURE SENSOR
Refer to figures 4 & 8 for mounting and wiring.
VELOCITY SENSOR (optional/not by Milltronics)
Connect the velocity sensor output to terminals 16,17 & 18 of TB-1 on the OCM II motherboard.
For virtually any cross sectional channel shape, a velocity sensor can be used in combination with the level from
the transducer to calculate the flowrate.
The OCM II is factory set to accept a standard 1 to 5 volt signal from the velocity sensor (for a 4-20 mA signal,
a 250 ohm 1/4 W resistor must be installed across TB1-16,17). However, the output from a velocity sensor within
a range of 0 to 10 volts and having a minimum span of 2.5 volts may be used.
Refer to Appendix B for instructions on re-scaling the input for velocity sensors.
INTERCONNECTION
All wiring must be performed in conjunction with approved conduit, boxes
and fittings and to procedures in accordance with all governing regulations.
Ensure the 9.53 Kohm load resistor across TB1-13, 14 is removed prior to temperature sensor connection.
If the optional data transfer link to a computer is used, the baud rate of the OCM II and computer must be the
same. This also applies to the serial printer if it is used. Set switch SW1 as follows:
SW1 POSITION BAUD RATE
(toggle down at)
1 - 9600
2 - 2400
3 - 1200
4 - 300
For Baud rates of 75, 150, 600 or 4800, set all SW1 toggles down at "open" and solder a jumper (J4, J5, J6 or
J7) onto the main board. Connect the communication cable to TB1-25 to 30.
Refer to figure 2 and Appendix C, Hardware Consideration.
Make sure that jumpers are properly set for standard 115 V AC or 230 V AC or special 100 V AC or 200 V AC
operation. Refer to figure 2 or see diagram on motherboard.
The main fuse must be installed. When making the power connection ensure that wires are securely fastened to
the proper terminals.
Do not operate with ground (earthing) wire disconnected.
Flip the power switch located at the lower edge of the motherboard "ON" and re-install the front panel. The unit
is now ready for start up.
■
91/02/14
PL-269 3 – 2
SECTION IV
START UP
GENERAL
Calibration of the OCM II is done via the front panel keypad. To provide clarity, all keypad entries are enclosed
within square brackets [ ] to distinguish them from other text.
The OCM II is designed to automatically prompt the user for each parameter in a particular sequence so that
none will be missed. Each parameter that is entered is then incremented to the next step required for the
selected primary element.
In order to prevent unauthorized or accidental alteration of data, all entries must be made through the
access / program mode F0, accessible via the following security code:
2.71828
PL-269 4 – 1
KEYPAD
"A" Auxiliary Functions
Used to select auxiliary parameters for Universal Head vs Flow Calculation applications
and perform printer functions.
"C" Clear
Used to clear reading display
"D" Display quantities
Enter [D#] [E]
Used to select any one of the ‘D’ displays
These are specific results of normal operation which the user may wish to view. The display mode is
continuously updated even while viewing in the "F" program mode.
e.g. D2 - Accumulated flow
D5 - Target range (Important aid in trouble shooting)
Refer to Table 1 for listing.
"E" Enter
Used to enter keypad selection as displayed and/or to scroll forward through displays or parameters.
"F" Function Mode
Enter: [F#] [E]
Used to select any one of the ‘F’ functions for performing special tasks.
e.g. F0 - Access/Programming
F7 - Setting the date
Refer to Table 2 for listing.
"P" Parameters
Enter: [P#] [E]
Used to select anyone of the ‘P’ parameters.
These are code numbers or values entered to tailor the OCM II operating system to the users requirements.
e.g. P2 - Primary element being monitored
P9 - Relay setpoint
Refer to Table 3 for listing.
91/02/14
PL-269 4 – 2
"R" Recall
Used to scroll backward through displays or parameters.
"U" Unit Parameters
Enter: [U#] [E]
Used to select any one of the ‘U’ unit parameters. These parameters set the physical characteristics unique
to the primary element being monitored. They have been separated from the other parameters in order
that the OCM II may prompt the user for each entry during calibration.
e.g. U0 - Expected flow at the calibration head
U3 - Exponent specific to the primary element
Refer to Table 4 for listing.
"0-9" Numeric Entries
" . " Decimal Point
" - " Negative Sign
KEYPAD ENTRY
Press desired keypad switches.
e.g. [P] [2]
Selection will be displayed in the "Reading" window.
Press [E] to enter selection.
Access parameters (U & P) or display and function code entries (D & F) are automatically shifted into the
"Mode" window after entry. However, code selections and values remain displayed in the "Reading"
window. After entry is made, mode is incremented to the next calibration step. If reading displays error,
refer to Appendix A for error codes.
DISPLAY
P4 17.8
MODE READING
Display
Description
F2 - H H indicates display of HEAD
F indicates display of FLOW
A indicates display of TOTAL FLOW
ERR 6 ERROR MESSAGE NO. 6
LOE LOSS OF ECHO
- - - - NUMERIC OVERFLOW
PASS DIAGNOSTIC ROUTINE, F13
ACCESS
RELAY
PL-269 4 –3
INITIAL START UP
The memory back-up battery must be installed
before turning the power switch on.
(refer to INSTALLATION section)
Flip SW-2 power switch ON. The OCM will display "F0" in the mode window and the transducer will begin firing.
The unit is now ready to be calibrated. Refer to the calibration chart, noting that:
After the access code is entered, the access light will illuminate confirming that the OCM II is accessible
for programming.
After an entry is made, the reading window will display the factory setting.
EXAMPLE:
Enter: [F0] [E]
Enter: [2.71828] [E]
The prompt in the left window will change to P0 and programming may proceed.
P0 = 0 Centimeters
P0 = 1 Inches
If centimeters is chosen:
Enter: [0] [E] or simply [E] as the present value is 0.
The next parameter, P1, is now displayed:
P1 = 0 Temperature in degrees Celsius
P1 = 1 Temperature in degrees Fahrenheit
If temperature in Fahrenheit is chosen;
Enter: [1] [E]
The next parameter on display is P2, primary element. As listed in Table 3, P2 may be set to any one value from
0 to 15, or 30 depending on the type of primary measuring device. The two following examples will illustrate the
use of this parameter.
PL-269 4 –4
Example 1
BS-3680 triangular weir, when P2=6 is entered, the OCM II will switch to the list of unit parameters required for
that type of flow calculation. If the prompting sequence is followed, none of the unit parameters will be
inadvertently omitted. The OCM II will switch back to "P" parameters once all necessary "U" parameters have
been entered.
a) U0 = Qcal
This is the calibration flow, i.e. the flow that is expected to occur when the liquid level is at hcal, the calibration
head. It may be entered in any engineering units and may be in units per second, units per minute, units per
hour or units per day.
In this case, hcal = 38 cm so that Qcal = 0.031273 m3 / s.
b) U1-time units of Qcal
We have chosen to have our calibration in flow units per second so we must enter U1 = 0.
c) U2 = hcal
This is the head at which the calibration flowrate defined by U1 and U2 will occur. In our case it is 38 cm.
d) U3 = The angle of the weir
We will also need to enter the angle of the weir’s V-notch which is 28 degrees 4 minutes or 28.06666 degrees.
We shall use U3 = 28.07.
We shall now enter these values beginning with U0, which at this point is displayed in the prompt window.
U0 = 0.03127 Enter [0.03127] [E]
U1 = 0 Enter [0] [E]
U2 = 38 Enter [38] [E]
U3 = 28.07 Enter [28.07] [E]
Now the display in the prompt window switches to P3 so that the next "P" parameters can be entered.
PL-269 4 –5
Example 2
Parshall Flume
Max. flow = 936 X 103litres per day
Max. head = 40 centimeters
Flowrate = K (Head)1.55 where K is a constant
1 Count = 1000 litres
Referring to Table 4 for "U" parameters, enter
P2 [0] [E] or simply [E] Primary element
U0 [936] [E] Max. flow
U1 [3] [E] Flow unit per day
U2 [40] [E] Max. head
U3 [1.55] [E] Exponential term
P3 refer to parameter listing Table 3.
P4 AND F12 AUTO ZERO ROUTINE
P4 is the distance measured from the face of the transducer to the level at which liquid flow will cease.
As the OCM II routinely measures the distance between the transducer and the liquid surface, it requires only
the distance that the liquid surface is above the zero level to be given to calculate P4.
Alternately, the Auto Zero Routine F12, will make the required calculation and enter the appropriate value for P4
automatically.
Enter: [F12] [E]
Enter: [current head]
"F12" & "calculation" will appear in the displays.
The current head is measured above the level at which flow would cease and must be
in the units of measure selected by P0.
When all the P and U parameters have been entered, the unit may be placed in operation unless data logging
functions are required. In such a case it is necessary to set the internal clock and calendar. As the data logging
function may be used for trouble shooting it may be desirable to set the time and date regardless.
For parameters P5, P6, P7, P11, P12, P13, P14, P15, P16, P17, and P18. Refer to Table 3. These parameters
are simple and self-explanatory from the list.
PL-269 4 –6
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