The DMM600 is a portable, battery-powered duff meter that accurately measures moisture content in duff material, which is critical to those conducting scheduled burns as well as those attempting to battle out-of-control fires. The DMM600 is a stand-alone device. (A datalogger is not required.) A sieve, carrying case, and software are included.Read More
The DMM600 uses measurement methods sensitive to the dielectric properties of the material being measured. It consists of a cylinder that houses the electronics, a sample chamber with a compression knob, and an LCD readout.
To measure duff water content, place the sample in the sample chamber and turn the compression knob until an audible indicator signals that the sample is properly compressed and the measurement is complete. Total time for measurement is about 30 seconds. Readings are displayed in real-time only; measurements are not stored.
The DMM600 was developed in cooperation with the USDA Forest Service, Rocky Mountain Research Station, and Missoula Technology and Development Center.
|Battery||9 V alkaline|
|Measurements per Battery||More than 2,000|
|Accuracy||±5% full scale range|
|Resolution||1% volumetric water content|
|Sieve Description||#4 mesh = 0.475 cm (0.187 in.)|
|Diameter||8.9 cm (3.5 in.)|
|Length||25.4 cm (10 in.)|
|Weight||1.7 kg (3.7 lb)|
Typical Current Drain
|Between Measurements||~3 mA (Goes into a low-power sleep mode after five minutes of inactivity.)|
|Sleep Mode||140 μA|
|During Measurement||85 mA for ~1 ms|
The DMM600 is a stand-alone product so data logger compatibility is not an issue.
PCDMM Software is supplied with the DMM600. It interfaces with the DMM600 using serial communications, and is used to download and upload calibration coefficients, monitor the battery voltage, and reset the DMM600.
A standard calibration converts the output of the measurement circuit to volumetric water content. User-derived calibrations can be downloaded using PCDMM software. These calibrations are useful when using the DMM600 with atypical materials. Guidance is provided in the operating manual for deriving calibrations. This feature can also be used with known duff bulk density to convert result to gravimetric water content. Measurements derived from the standard and user-defined calibrations are alternately displayed on the LCD if a user-defined calibration has been downloaded.
The DMM600 comes with a sieve and case. The sieve fits in the opening of the sample chamber. Duff is moved through the wire mesh of the sieve to break up large fragments and improve measurement accuracy in duff materials with a large range of fragment sizes.
The case eases transport and provides storage for the sieve and small items such as a spare battery, screwdriver, and pencil.