9
Version 2.1
Update: April 2016
PONSEL Mesure
– Aqualabo Contrôle
35 Rue Michel Marion
– 56850 CAUDAN, FRANCE
Tel.: +33(0)2 97 89 25 30
– Fax: +33(0)2 97 76 55 72
2.2.4 NTU sensor: Turbidity in NTU-mg/l.
The measuring principle is based on nephelometry: a diode emits infrared light (850 nm) and an IR
receiving diode, set to one side at an angle of 90°, detects the amount of scattered light (standardized
measurement). The sensor can be calibrated using a Formazine standard.
This very economical optical technology requires very little maintenance and no consumables.
Measurements
Measurement principle
Scattering of IR at 90°
Measurement ranges
0 to 4,000 NTU in 5 ranges
:
0 - 50 NTU
0
– 200 NTU
0
– 1,000 NTU
0
– 4,000 NTU
AUTO range
0 to 4,500 mg/L range
Calibration:
0-500 mg/L range, as per
standard NF EN 872
range >500 mg/l as per standard
NF T 90 105 2
Resolution
from 0.1 to 1, set automatically as a function of the range
Accuracy
< 5% of the NTU value recorded
Response time
< 5 s
Operating temperature
0 °C to + 50 °C
Temperature measurement
Via an NTC thermistor
Storage temperature
-10 °C to + 60 °C
Signal interface
Modbus RS-485 as standard and SDI-12 as an option
Maximum refresh rate
< 1 second
Power supply to sensor
5 to 12 volts
Power consumption
Standby: 40 µA / Warm-up time: 100 mS/ Current pulse: 500 mA
When sending via RS-485 (1 measurement/second): 820 µA
When sending via SDI-12 (1 measurement/second): 4.2 mA
Sensor
Dimensions
Diameter: 27 mm; Length not including cable: 170 mm
Weight
300 g (with 3 meters of cable)
Materials
PVC, POM-C, PMMA, Polyamide
Maximum pressure
5 bar
Cable/connection hardware
9-wire shielded conductor, uncoated-strand polyurethane sleeve
Ingress protection rating
IP68