ABB 4670 Series User Manual page 38

...8 SPECIFICATION
7997-300 Turbidity Sensor
Range
Programmable 0 — 100 FTU to 0 — 500 FTU
and 0 to 1000mg/l (or ppm) *
Measurement Principle
Transmitted light
Measurement Characteristic
Logarithmic based on Formazine
Resolution
1 FTU
Repeatability
Better than 1% of span
Accuracy
±2% of FSD
(limited by uncertainty in Formazine standards)
Temperature drift
0.2 FTU/°C (0.1 FTU/°F)
Response time
Varies with flow rate, typically 90% step change in
2 minutes at 1 l/min
Flow rate
0.5 l to 1.5 l/min
Integral wiper cleaning system
Programmable operational frequency every 0.25 hour, 0.5 hour,
0.75 hour or in multiples of 1 hour up to 24 hours
Sample operating temperature
0 to 50°C (32 to 122°F)
Pressure
Up to 3 bar (43.5 psi)
* Note. The maximum range for suspended solids measurement is
dependent upon the coefficient value of the sample.
36
7997-400, 7997-401 Dip & 7997-405
Flow Turbidity Sensors
Range
Programmable 0 — 100 to 0 — 1000 FTU
and 0 — 2000mg/l *
Extended Range
0 to 2000 FTU
Measurement Principle
Transmitted light
Measurement Characteristic
Logarithmic, based on Formazine
Resolution
1 FTU
Repeatability
Better than 1% of span
Accuracy (0 to 1000 FTU)
±2% FSD
(limited by the uncertainty of Formazine)
Accuracy (0 to 2000 FTU)
Better than ±10% of span
Temperature drift
0.2 FTU/°C (0.1 FTU/°F)
Flow rate (7997-405 only)
0.5 to 2 l/min
Integral wiper cleaning system
Programmable operational frequency every 0.25 hour, 0.5 hour,
0.75 hour or in multiples of 1 hour up to 24 hours
Sample operating temperature
0 to 50°C (32 to 122°F)
Dip stem length
7997-400 1m (3.3 ft)
7997-401 2m (6.6 ft)
Pressure (7997-405 only)
Up to 3 bar (43.5 psi)