Hach-Lange 3400 sc - Manual (Page 31)

27
Troubleshooting
6.4.2 Analog or External Digital Gateway Sensors
1. Disconnect the sensor from the analyzer or junction box.
2. Clean the sensor using the procedure in "Cleaning the Sensor" on page 23 .
3. Obtain a known standard (NIST-traceable is preferred for many applications) and take
a measurement.
4. Reconnect the sensor to the controller or junction box.
5. If the resulting measurement is out of specification (different from the value stated on
the label ± the stated standard error), contact Technical Consulting Services. See
"Adresses" on page 33 for contact information.
Table 10: Sensor Operations (Resistance) Checks for Models 3433
Measurement Points Correct Resistance Readings
Between blue and white wires 1089–1106 ohms at 23–27 °C
Between black and red wires Infinite (open circuit)
Between black and white wires Infinite (open circuit)
Between red and white wires Infinite (open circuit)
Between red and inner shield wires Infinite (open circuit)
Between black and inner shield wires Infinite (open circuit)
Between white and inner shield wires Infinite (open circuit)
Between outer and inner shield wires Infinite (open circuit)
Table 11: Sensor Operations (Resistance) Checks for Models 3422 and 3455
Measurement Points Correct Resistance Readings
Between blue and white wires 1089–1106 ohms at 23–27 °C
Between red wire and sensor body Less than 5 ohms
Between black wire and inner electrode Less than 5 ohms
Between black and red wires Infinite (open circuit)
Between black and white wires Infinite (open circuit)
Between red and white wires Infinite (open circuit)
Between red and outer shield wires Infinite (open circuit)
Between black and outer shield wires Infinite (open circuit)
Between white and outer shield wires Infinite (open circuit)
Between outer and outer shield wires Infinite (open circuit)