Hach LDO AQS sensors, User Manual, Page: 9 / 60

Table 3 Salinity (PSU) per conductivity value (mS/cm) (continued)
mS/cm PSU mS/cm PSU mS/cm PSU mS/cm PSU
8 5 19 13 30 21 42 30
9 6 20 13 31 22 44 32
10 6 21 14 32 22 46 33
11 7 22 15 33 23 48 35
12 8 23 15 34 24 50 37
13 8 24 17 35 25 52 38
14 9 25 17 36 25 54 40
15 10 26 18 37 26
Maintenance
W A R N I N G
Multiple hazards. Only qualified personnel must conduct the tasks described in this section of the
document.
Maintenance schedule
The maintenance schedule shows minimum intervals for regular maintenance tasks. Perform
maintenance tasks more frequently for applications that cause electrode fouling.
Note: Do not disassemble the probe for maintenance or cleaning.
Maintenance task Recommended minimum frequency
Clean the sensor 90 days
Inspect the sensor for damage 90 days
Replace the sensor cap 2 years or more frequently, if necessary
Clean the sensor
Clean the exterior of the sensor with a soft, wet cloth.
Note: If the sensor cap must be removed for cleaning, do not expose the interior of the cap to direct sunlight for
extended periods of time.
Change the sensor cap
W A R N I N G
Potential explosion hazard. The sensor setup cap is not rated for hazardous location use.
Replacement sensor caps and setup caps are shipped with installation instructions. Refer to the
included instructions to change the cap. After the new sensor cap is installed, make sure that the lot
number on the sensor cap is the same lot number that is read by Modbus. The sensor uses the
calibration information from the sensor cap.
For best performance and accuracy, replace the sensor cap:
• Every two years, or more frequently if necessary
• When routine inspection shows significant erosion of the sensor cap
English 9