Fuel Moisture

CS506 Fuel Moisture Sensor

Our fuel moisture sensor, the CS506, reports the status of small-

diameter (10-hour) forest fire fuels as percent moisture by weight

(1%=1 g water/100 g dry fuel). It consists of an epoxy-encapsu-

lated electronics package that uses time-domain reflectometry

(TDR) technology to measure the moisture content of the #26601

10-hour Fuel Moisture Stick. The sensor produces a ±0.7 Vdc

square-wave frequency that is read using an analog or pulse

channel on a Campbell Scientific datalogger. The datalogger then

converts the frequency measurement to percent fuel moisture

via a quadratic calibration.

#26601 10-Hour Fuel Moisture Stick

The

#26601 10-hour Fuel Moisture Stick consists of a ponderosa-

pine dowel fabricated to USFS specifications. It has a 0.5 in.

diameter and a 20 in. length—the same dimensions as those

used on the traditional weighing fuel moisture racks. Each dowel

has undergone two additional sorts to optimize probe-to-probe

repeatability and to allow probe interchangeability without indi-

vidual calibration. The response of the CS506 sensor is similar to

the traditional weighing racks because the entire dowel surface is

exposed for moisture exchange.

The CS506 Fuel Moisture Sensor requires the purchase of a

#26601 10-hour Fuel Moisture Stick.

CS506 Fuel Moisture Sensor

#26601 10-hour

Fuel Moisture Stick

#26817 Fuel Moisture/Temperature Mounting Stake

The #26817 Mounting Stake is often used to mount the sensors

in the field. This stake places the CS506/26601 and the

CS205/107 probes twelve inches above the forest floor.

Because the probes are mounted parallel to each other,

shadowing is minimized. Cable ties are included for securing the

cables to the side of the stake.

CS516 Fuel Sensors for RAWS Stations

The CS516-QD and CS516-LQ are intended for our Remote Au-

tomated Weather Stations (RAWS). They consist of a CS506 Fuel

Moisture Sensor, a #26601 10-hour Fuel Moisture Stick, a CS205

Fuel Temperature Stick, and a 107 Thermistor mounted on a

#26817 Fuel Moisture/Temperature Mounting Stake.

CS516-QD

With the CS516-QD, the cables for the CS506 and 107 sensors

have a 12 ft length and are fitted with a military-style connec-

tor. The connector attaches to the enclosure of a RAWS-F Quick

Deployment Fire Weather Station.

CS516-LQ

With the CS516-LQ, the cables for the CS506 and 107 sensors are

also fitted with a military-style connector, but the cables have a

user-specified length. The CS516-LQ is intended to be used

with the RAWS-P Permanently Mounted Station.

CS506 Fuel Moisture Sensor

CS205 Fuel

Temperature Stick

#26601 Fuel Moisture Stick

107 Temperature Probe

This view shows how the instruments fit into the #26817

Fuel Moisture/Temperature Mounting Stake.