NEP390 Handheld Turbidity Meter

  • Choice of Turbidity Ranges 40NTU, 100NTU, 400NTU and 1,000NTU
  • Ideal for most applications
Product Options


The ANALITE 390 series of microprocessor based handheld turbidity meters are designed for applications where turbidity levels of up to 1,000NTU may be encountered. Ranges can be set by the user at 40NTU, 100NTU, 400NTU and 1,000NTU. There are four probes available which complete the ANALITE 390 series: NEP390, NEP391, NEP395 and NEP396 which can all be operated at depths of up to 100 metres (approx 330 feet).

Where applications are required in fast cold running water or for short monitoring deployment the NEP390 and NEP391 turbidity meters are ideal. Where bio-fouling and sedimentation build up is likely to be encountered the NEP395 and NEP396 turbidity meters have been specifically designed with an integral wiper assembly which can be initiated automatically (periodically) via a direct RS232 command or manually as required.

All turbidity probes almost totally reject fluctuating ambient light conditions due to a unique modulation technique. Plus use 90?optics and employ infrared light in accordance with ISO7027.

Calibration can be carried out at any time or have later firmware uploaded by the user via the RS232 interface.

Two cable connection systems are available. The standard version employs a marine grade connector to terminate the cable to the turbidity probe, whereas the G version has the cable permanently connected to the probe via a waterproof gland.

Manufactured by: McVan
Model: NEP390 Handheld Turbidity Meter

Services offered for this product

  • Sales
  • Rental
  • Installation
  • Calibration
  • Maintenance


Monitoring of streams and rivers
Monitoring of water storage bodies including stratification studies
Intermediate and final effluent treatment monitoring
Hydrological run off studies
Ground and bore water analysis
Drinking water filtration efficiency
Industrial process monitoring
Sludge and dredge monitoring


Technique 90° modulated infra-red (ISO7027).
Ranges 40, 100, 400 and 1,000NTU - range selection
set by user, initially set at 100NTU. Other
range values available at additional cost up to
Resolution Range:
Repeatability ±1% at 25°C.
Linearity Better than 1% for 40NTU, 100NTU and 400NTU, 3% for 1,000NTU.
Temperature Coefficient Better than ±0.05%/°C.
Repeatability ±1% at 25°C
Linearity Better than 1% for 40NTU, 100NTU and
400NTU, 3% for 1,000NTU
Temperature Coefficient Better than ±0.05%/°C
Outputs All models - RS232 - 1200BPS, 7 data bits,
even parity, one stop bit.
NEP390/395 - SDI-12 Protocol (V1.3).
NEP391/396 - Analogue Voltage (0-1V or 0-
2.5v), minimum load 3kohms and Analogue
Current (4-20mA or 0-20mA), maximum load
350 ohms.
Measurements RS232 and SDI-12 interfaces
Latest turbidity measurement -1 sample.
Mean and Sample Variance (over 100 samples).
Median (over 100 samples).
Minimum (over 100 samples).
Maximum (over 100 samples).
Probe supply voltage.
Probe internal temperature.
Analogue Interface
Analogue representation of the level of
turbidity as a proportion of the range selected.
Approximate update rate is 0.5 seconds. Voltage
and current outputs operate concurrently.
Calibration 2 or 3 point calibration for each range.
May be set by the user only through the RS232 interface and for the range selected.
Can revert back to factory calibration settings
after user calibration.
Power 9.6 - 16V dc, 35mA ON. 60mA ON and wiping for NEP395 and NEP396 only. STANDBY of 1.5mA on NEP390 and NEP395 only.
Add a provision for an additional 20mA for the
NEP391/396 if the 0/4-20mA output is used.
Wiping Initiated by wipe or autowipe $ commands
under the RS232 interface or M8! command
under SDI-12 or for the NEP396 only it can be
externally initiated by momentarily (>50msecs)
bringing the RS232RX conductor to the 0V
Wipe Time 6 seconds nominal.
Weight NEP390/391 - 500gms - probe only, 100gms
connector plus 70gms per meter of cable.
NEP395/396 - 550gms - probe only, 100gms
connector plus 70 gms per meter of cable.
Dimensions NEP390/391- 250mm long unmated, 321mm
long mated to end of protective boot, 32m dia.
NEP390G/391G- 292mm long including
glanding and strain relief assembly, 32mm
NEP395/396- 256mm long unmated, 327mm
long mated to end of protective boot, 32m dia.
NEP395G/396G- 299mm long including
glanding and strain relief assembly, 32mm
Construction Stainless steel casing with protruding
castellations to protect the plastic fibre-optic
Cable connection via 7-way waterproof
connector (standard version), or probe cable is
glanded directly from the rear of the probe via
an integrated plastic strain relief (add suffix G to
standard version).
Cable NEP390/395 - 5 core + shield, 6mm dia. PUR
sheath . Conductor resistance 45 ohms per km.
NEP391/396 - 7 core + shield, 6.5mm dia. PUR
sheath. Conductor resistance 75 ohms per km.
Cable Length To order - 60m (200ft) maximum for NEP390/
, 99m (330ft) maximum for NEP391/396.
Depth Rating 100m (330ft)
Operating Temperature -10°C to 40°C
Storage Temperature -20°C to 50°C


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