Lowell Instruments Tilt Current Meter

Description

Overview

The TCM-1 is ideal for measuring water velocity from inland to the edge of the continental shelf, its simple design and lower cost making it feasible to measure current in many locations simultaneously.

This tilt current meter is field configurable for either low or high current range by simply adding or removing a calibrated ballast weight. The ballast washer is recommended for lower currents consistently under 40 cm/s. Housed rugged PVC, with no external sensors, the TCM-1 is easy to deploy and recover. The built-in data logger includes a USB communication interface, a microSD flash memory card, and a long-life lithium battery.

How does the Tilt Current Meter Work?

The TCM-1 Tilt Current Meter measures current using the drag-tilt principle. The data logger is buoyant and anchors to the bottom via a short flexible tether. Moving water tilts the data logger in the direction of flow. Measuring with a 3-axis accelerometer and 3-axis magnetometer for measuring tilt and bearing, the meter’s resulting orientation data is converted to current by applying calibration coefficients.

Features

300 meter depth rating
Measures water velocity for a fraction of the cost of an acoustic meter
Tilt compensated compass for bearing measurements
Simple, rugged, low maintenance design
Seaweed snag-resistant
Change range in the field without software
8 GB MicroSD memory card virtually eliminates memory concerns
Temperature sensor accurate to +/-0.1C
Lithium battery allows continuous 4Hz sampling for more than 1 year
USB 2.0 with standard cable and drag and drop data file offload

Specifications

Speed (Low Range w/ Ballast Washer)

Range: 0-40 cm/s

Accuracy: 2 cm/s + 3% of reading

Resolution: 0.1 cm/s

Speed (High Range w/ Ballast Washer)

Range: 0-80 cm/s

Accuracy: 3 cm/s + 3% of reading

Direction

Range: 0-360°

Accuracy: 5° (for speed >5 cm/s)

Resolution: 0.1°

Temperature

Range: -5 to 30 °C

Accuracy: 0.1 °C

Resolution: <0.005 °C

Range: -20 to -5, 30 to 50°C

Accuracy: 0.2 °C

Resolution: <0.01 °C

Electronics

Memory: 8 GB microSDHC flash card (standard)

Communications: Full speed USB micro-B port

Battery Type: Months to years depending on recording rates

Internal Clock: < 1 minute of error per month

Operating Modes

Start and Stop: Start and Stop at user defined times

Burst Mode: Variable rate logging at user defined interval

Recording Rate:

Current: 64 Hz to 1 sample per hour with typical settings of one 20 second burst @ 8 Hz per minute (12-month battery life)

Temperature: 1 Hz to 1 sample per hour

Mechanical

Minimum Depth: 76 cm (30 in)

Depth Rating: 300 m (1000 ft)

Dimensions:

Diameter: 2.7 cm (1.05 in)

Length: 73 cm (28.75 in) not including lanyard

Weight: 340 g (12 oz)

Construction: Gray PVC housing with EPDM O-ring

Software

User Interface: Domino for Windows® – Free Download

USB: USB 2.0 compliant MSC and CDC Classes

Firmware: Field upgradable via USB cable

Data Sheet