Specification - ABB 4670 Series User Manual

8 SPECIFICATION

7997-200 Turbidity Sensor
Range
Programmable 0 — 25 NTU to 0 — 250 NTU and
0 — 500mg/l (or p.p.m.) *
Measurement Principle
90° scattered light measurement. Compliant to ISO7027
Measurement Characteristic
Linear based on Formazine
Resolution
0.1 NTU
Repeatability
Better than 1% of span
Accuracy
±2% of FSD (limited by uncertainty in Formazine standards) from
0 to 100 NTU
±5% from 100 to 250 NTU
Temperature drift
0.005 NTU/10°C (0.003 NTU/10ºF)
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 multiples of 1 hour up to 24 hours
Sample operating temperature
0 to 50°C (32 to 122°F)
Sample 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.
7997-201 & 7997-202 Turbidity Sensors
Range
Programmable 0 — 1 NTU to 0 — 30 NTU
Measurement Principle
90° scattered light measurement. Compliant to ISO7027
Measurement Characteristic
Linear based on Formazine
Resolution
0.01 NTU
Repeatability
Better than 1% of span
Accuracy
±2% FSD (limited by uncertainty in Formazine standards)
Temperature drift
0.005 NTU/10°C (0.003 NTU/10ºF)
Response time
Varies with flow rate, typically 90% step change in less than
45s at 1 l/min
Flow rate
0.5 l to 1.5 l/min
Integral wiper cleaning system (7997-201 only)
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)
Sample pressure
Up to 3 bar (43.5 psi)
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