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A ChannelMag microprocessor type CMM calculates flow from the mean velocity and level sensor inputs.
The CMM microprocessor incorporates a 2-way RS232 communication loop and datalogger
| ChannelMag Feature |
Benefit |
| Patented coil excitation 1-5A @ 40 Hz |
Produces a high accuracy linear signal across ChannelMag electrodes, unaffected by permanant coating eg. sewage, grease, calcium carbonate, and similar. NO SENSOR CLEANING NECESSARY. |
| Suitable for use in existing channels up to 20 feet (6 m) wide |
No restrictions, no gradients, no costly flumes required. Complete velocity profile compensation. |
| Calibrated NIST traceable accuracy |
Suitable for custody transfer, with improved accuracy and rangeability over standing waving flumes |
| Solid state sensors, no moving parts |
Virtually maintenance free |
| May be installed with existing standing wave flumes |
Documented flow check on critical flow application |
ChannelMag Method of Operation
The ChannelMag is suitable for open channels having diverse cross sectional shapes and up to nominally 20 feet (6 m) wide x 12 feet (3.6 m) deep.
The ChannelMag incorporates a CM2 flat bed magnetic flow sensor, which may be bolted to the bottom of an existing channel or into a recess of the floor of the existing channel. For channels normally greater than 24 inches (600 mm) wide, magnetic enhancement plates are bolted to the sides of the channel, which completes a magnetic field over the entire cross sectional area of the flow stream. Sufficiently large CM2 sensors account for variation in velocity profile and true volumetric is measured. Both flow and level sensors, together with magnetic enhancement plates when necessary, are calibrated in a long low tank over the required velocity range. A NIST traceable calibration certificate is issued with each ChannelMag (USA National Institute of Standards and Technology).
The CM2 sensor operates using Faraday's Law, where a conductor moving in a magnetic field induces a voltage, the amplitude of which is proportional to the velocity of the conductor. The conductor is the media being measured. Large conical electrodes in the CM2 measure the mean velocity of the media. The electronics incorporate Advanced Flow Technology's patented pulsed AC technology. The powerful magnetic field is created by energizing the coils with 1-5 Amps at a frequency of 40 Hz (for a 60 Hz power supply). This combination provides a signal to media noise ratio typically 50 times better than traditional magmeters. As such, the electrodes may be permanently covered with sewage grease, calcium carbonate, and similar, without accuracy being affected. No cleaning is necessary.
The level measurement utilizes a Milltronics XRS-5 ultrasonic transducer. The level transducer continuously transmits high frequency sonic pulses to the media surface and senses the reflected echoes on the return. The time from transmission to return is proportional to level. An integral temperature sensor automatically compensates for changes in the ultrasonic sound velocity caused by air density changes.
The level transducer is suitable for methane, saltwater, and caustic environments and is submersible.
ChannelMag Flowmeter Microprocessor CMM
The ChannelMag Microprocessor CMM receives a signal from a DeltaPulse magnetic flow transmitter. The DeltaPulse also powers the coil of the CM2 sensor and conditions its signal. The ChannelMag Microprocessor receives the level signal and computes the volumetric flow. The basic equation performed is:
Q = K V Hn where:
K = calibration constant
V = mean velocity
H = level
n = exponent depending on shape of channel
The ChannelMag Microprocessor offers two-way communication via RS232 with a modem. It may be programmed via a computer keyboard or through a computer file. You can upload or download parametersa and download data. Using a modem, the signals can be transmitted over telephone lines. For back-up security, parameters can be downloaded and later re-sent to the unit to re-initiate programming.
The data-logging rate is adjustable from once per minute to once a day. It records the average flow rate for that time period. Daily, it records min./max. of temperature and flow rates, and the time is occured, as well as the daily total. Advanced functions include variable rate logging. In case of a rapid change in flow, the unit can be preprogrammed to log at a higher rate. This provides for a detailed profile of the flow change event.
Inputs
0 - 10 V from DeltaPulse magnetic flow transmitter
Input from XR-5 ultrasonic level transducer
Power Supply
115/230 Vac + or - 15%, 50/60 Hz @ 16 VA Max., 9 - 30 V dc @ 8 W Max., 3.5 W min.
Transducer
ST-25C, ST-25B
Separation
Up to 100 m (300 ft) between transducer and electronics using RG 62U coaxial cable.
Level Range
Min. 0 - 1 ft (300 mm). Max. 0 - 16.5 ft (5 m)
Minimum Dead Band
12 in. (300 mm)
Outputs
3 relay outputs - SPDT contacts rated 8A/250 Vac; function programmable
Display
Two line alphanumeric LCD type with LED backlighting
Data Logging
Rates - fixed, plus, selected variable - 1, 5, 15, 30, 60 minutes or 24 hours
ChannelMag Flowmeter Microprocessor CMM
Maximum Duration
31 days @ 1 min. entries
135 days @ 5 min. entries
305 days @ 15 min. entries
2.2 years @ 24 hour entries
Log Contents
Site identification number, date and time of each record, flow rate entries, daily flow, max. and min. flow rates and temperature with times of occurence.
Log Format
ASCII or data base manager (spreadsheet compatible), converted by a utility software provided.
Communications
User interface via detachable IR keypad programmer. RS232 compatible seal port/bi-polar + or - 20 mA current loop - port for programming or extraction of program data or data log. RS232 port capable of periodic output to serial printer; 7 selectable baud rates from 300 to 19200
Software
Milltronics Utilities Software COM1 or COM2 5.25" and 3.5" PC floppy disk for DOS 3.1 and up.
Operating Temperatures
(Electronics) - 10 to 50 degrees C (14 to 122 degrees F)
Temperature Compensation
Resolution 0.1 degrees C; linearity + or - 0.2 degrees C
Resolution
Liquid head - 0.2 mm (0.007 in.)
Current output - 5 micro A, 12 bit D/A
Accuracy
+ or - 1 mm/m, calculated error less than 0.02%
Memory Protection
Dual back-up systems - super capacitor and Ultralife lithium power cell
Enclosure Rating
Polycarbonate, CSA enclosure Type 4, IP65, NEMA 4X
DeltaPulse Transmitter
Model DPAC2 (see separate data sheet)
ChannelMag Flowmeter Specifications
Calibrated Accuracy
+ or - 2% of rate for velocities > 2 fps (0.6 m/s), with min. level 2" (50 mm) + or - 0.04 fps (0.012 m/s) for < 2 fps
Adjustable Velocity Range
0 - 2 fps (0 - 0.6 m/s) to 0 - 10 fps (0 - 3 m/s)
ChannelMag Sensor CM2
Standard Widths
8", 24", 40", 72" (200, 600, 1000, 1830 mm)
CM2 Sensors are arranged in singles or pairs, suitable for up to 20 foot (6 m) channels. See "Dimensions and Weights" in this specification.
Body Material
PVC with stainless steel brackets and bolts
Electrodes and Grounding
316 stainless steel
Electrode Seals
Viton
Protection
NEMA 6 and IP68 to 30 feet wg/10m wc
Cable Length
30 feet standard supply
2-core shielded 18 AWG (0,75mm2)
Max. 300 feet (100 m) optional
Maximum Media Temperature
140 degrees F (60 degrees C)
Maximum Level
30 feet wg (10 m wc)
Magnetic Enhancement Plates Material
Power coated polyethylene carbon steel
Dimensions
See drawing in this specification
XR-5 Level Transducer
Level Range
0 - 1 to 16.5 feet (0.3 to 5 m)
Temperature Compensation
Integral
Construction
PVDF body with polypropylene emitter face
Protection
NEMA 6 and IP68 with submergence shield
Weight
2.6 lb (1.2 kg)
Conduit Connection
1" NPT male
Operating Temperature
-4 degrees F to +150 degrees F (-20 degrees C to +65 degrees C)
Cable Length
30 feet standard supply, 2-core shielded 18 AWG (0.75mm2) Max. to 300 feet (100 m) optional using coaxial cable RG-62 A/U
ChannelMag Flow Sensor CM2
Dimensions and Weights
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