SediMeter™ model SM3A
The SM3A model is the base model and has no cleaner. It has a cable connector in the top end (although we can also put it in the bottom if so desired). The diameter is only 15 mm from end to end. It is powered by a size AAA recheargeable battery.
If you require an instrument with a mechanical cleaner consider either the SM3B, or go with an SM4 that lacks moving parts. The SM3A will work for bottom level monitoring even under fouling conditions by applying copper tape on the rear side of the sensor. There is also a promising clear anti-fouling paint on the market.
Features in common for all SM3 models of 2017:
The sensor consists of 36 near infrared optical backscatter detectors (NIR OBS) spaced 1 cm apart. The active measurement length is 35 cm. Turbidity is measured at 71 levels, every second one as straight backscatter and avery second one as oblique backscatter, and reported in formazin turbidity units (FTU) with no decimals. The level is estimated with 0.01 mm resolution.
There is an identical optical backscatter detector located 11 cm above the others. It is used to measure straight backscatter turbidity as a separate variable. The instrument also reports temperature and battery level at each measurement.
Burst samples of up to 20 samples of turbidity and level can be taken in each measurement, with a time interval of 1 s to 16 s between the burst samples. This allows for detecting differences during a wave period, for instance. The time interval between measurements is from 3 seconds to 24 hours.
The SediMeter has a built-in memory that holds 16,384 measurements. It can also be used in real-time monitoring, alone or in a network. When used in stand-alone mode it is powered by a built-in battery that is recharged through the same USB cable used to set up the instrument and to download data.
The instrument can be mounted in sediment using the standard anchor and holder tube included if purchasing a kit. This holder is screwed down in mud and sand with the help of a handle.
The instrument is available separately or as a kit in a convenient case, complete with all necessary accessories for stand-alone use in the field (handle, anchor, holder tube, cable, blind plug).