Current Loop Monitor

Maretron CLM100-01 Current Loop Monitor

A universal 4-20mA to NMEA 2000 bridge — connects virtually any commercially available 4-20mA analog transducer to the NMEA 2000 network, putting its data on every compatible display on the boat.

Why It's Worth It
The 4-20mA current loop is the most common standard for industrial and commercial sensors — covering pressure, temperature, flow, vibration, humidity, force, angle, shaft speed, and dozens of other measurands. The CLM100 converts any of those signals to NMEA 2000 data without needing a custom interface or a dedicated display wired to the sensor. One CLM100 per transducer; the data is then available at any Maretron display, N2KView installation, or vessel monitoring software on the network. The ±0.33% full-scale accuracy means the CLM100 itself adds minimal error on top of whatever accuracy the transducer itself provides.

Practical applications include vibration monitoring of pumps, motors, fans, compressors, and gearboxes (provides early warning of bearing wear before catastrophic failure), shaft speed monitoring via a rotational rate transducer, mast stay load monitoring via a clevis pin load cell, and any pressure, temperature, or flow measurement where a 4-20mA transducer is the available sensor.

Use
Connects to the NMEA 2000 network via standard Micro-C. Transducer connects via screw terminals inside the module housing. Mount in any orientation in a dry or damp location — note IP64 (not IP67 like most Maretron modules), so avoid direct water spray or submersion. Mount away from engines where temperature exceeds 130°F (55°C). Configuration requires a Maretron DSM150, DSM250, USB100, or IPG100; configurable parameters include the physical quantity being measured, the 4mA and 20mA calibration values, and a damping constant (0.2–25.0 seconds) for smoothing noisy transducer signals.

Supported Measurands (via 4-20mA Transducer)
DC Voltage, DC Current, Flow Rate, Distance, Linear Velocity, Linear Acceleration, Angle, Angular Velocity, Angular Acceleration, Temperature, Humidity, Resistance, Strain Gauge, Force (Load Cell), Pressure, Decibels, Rotational Rate