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Hydro Services Current Meter Counter Signal Processor
The Hydrological Services Current Meter Counter Signal Processor (CMCsp) is a small electronic device that can be used to measure flow velocity from most any mechanically rotating current meter. A superior feature of the CMCsp is its ability to "clean" the signal and interface directly to a PDA, PocketPC, or other computing device and provide serial data that can be used by the external device to compute discharge. Meters using a cat whisker head and ball and wire contact to perform a mechanical switch closure can be used with the CMCsp to produce a clean, noise-free signal. To measure and compute velocity, the CMCsp provides a User Serial Interface Program (USIP). This USIP is used to enter the rating of the current meter and can support up to two meters with each meter having up to three rating equations with three rotations/sec ranges.
Hydrological Services CMCsp Current Meter Counter Signal Processor
The Hydrological Services Current Meter Counter Signal Processor (CMCsp) is a small electronic device used to "clean" the signal from a mechanically rotating current meter such as a Price AA or Pygmy meter and directly reads the velocity on the LCD as well as interfacing to a PDA for computation of velocity and discharge. Meters using a cat whisker head and ball and wire contact to perform a mechanical switch closure can be used with the CMCsp to produce a clean, noise-free signal.
Whenever the CMCsp is connected to a hand-held computer and the current meter bucket wheel completes a contact closure, the CMCsp can simultaneously produces four responses:
1) Sounds a buzzer tone
2) Emits a flash from an LED indicator on the front panel
3) Updates the LCD count and timer, and
4) Transmits a serial data value at 1-second intervals representing the number of contact closures and elapsed time through the serial interface.
The CMCsp uses two AA batteries for operation and is connected between the current meter and the hand-held computer using either a connecting lead or an optional Bluetooth wireless interface. A program running in the hand-held computer sends commands to the CMCsp to perform a measurement.
The most important operating features of the CMCsp are as follows:
1- Direct Velocity Reading
2- User Serial Interface Program for entering 2 current meters with up to 3 rating equations for each current meter.
3- The ability to signal process each contact closure from any type of meter. For cat whisker contacts, this becomes extremely important since cat whisker contacts offer the poorest quality for marking and counting rotations.
4- The CMCsp offers 2 modes of operation, i.e. NORMAL and SLOW speed mode. NORMAL is selected for meter rotations >0.25 ft/sec while SLOW mode is for velocities below 0.25ft/sec. To improve noise rejection, the sample rate of the input signal at the SLOW speed mode (lower velocities) is 1/10 of the sampling rate that occurs during
5- The ability to detect faulty connections from the meter through the wading rod to connected CMCsp. During power up of the CMCsp, a calibration of the input signal is performed.
6- The ability to detect a signal short during a measurement. If such a condition is detected, the ‘*’ symbol is displayed until the fault condition is removed.
• Direct Velocity Reading
• Digitally processes and ‘cleans’ signals
• Works in high conductivity water( > 50,000μSiemens)
• LCD display showing total meter counts and elapsed time
• Uses simple single character commands
• Signal Driver for AquaCalc(s), Sutron DMX and Hydrological Services CMC Series
• Fully compatible with USGS QCALC Discharge Measurement Software
• Fully self calibrating; ‘Self Test’ for Serial Interface setup
• Can be used to adjust Current Meter ‘Dwell Angle’
• Can display and produce ‘Spin Test’ record
• Selectable 10 second to 90 second fixed measuring intervals; default is 40 seconds
• ‘Starts’ and ‘Ends’ measurement on a meter contact closure
• Total Counts to 999, Total Time to 999.9 seconds
• Continuous measuring mode (no time limit)
• Low battery indication
• Automatically indicates fault conditions
Bluetooth Class 2 / Output power 2.5mW (4dBm)
Compliant Bluetooth Spec V1.1
Up to 30ft (10m) range (operating at 2.4GHz)
Communications RS232 Port (Tx, Rx) @ 19200 baud 8/N/1
Connections 1 x Switchcraft #820 ¼” Jack Socket (Meter input) 1 x sub miniature 5 pin socket (RS232 + filtered meter o/p)
Indicators 8 character x 2 line LCD, 1 x Orange LED, 1 x Red/Green/Blue LED
Power Source 2 x Internal AA alkaline 1.5V batteries
Low battery indication 2.8V
Dimensions 120mm x 80mm x 22mm (L x W x D)
Weight 218 grams (with batteries)
Environmental -5oC to + 50oC, Non Condensing (Splashproof - No IP rating)
CMCsp Current Meter Counter Signal Processor