Hach-Lange 1720E Low Range Turbidimeter - Manual (Page 25)

21
Operation
serial number). As long as the verification exists within the verification history, the expected value will
be retained. Otherwise, the expected value will be the nominal value associated with the dry
verification device.
10. Select the VERIFICATION type (begin at step 5 in section 5.5.3.1 on page 21 for dry
verification or section 5.5.3.2 on page 21 for wet verification) or enter initials to
complete calibration.
11. Return the sensor to measure mode and confirm.
5.5.3 Instrument Verification
Instrument verification is intended as a simple check to ensure Turbidimeter functionality
between calibrations. Two types of verifications are offered. The dry verification is
performed using a “dry” calibration device such as the ICEPIC™. A wet verification is
performed using a standard with a predetermined value such as StablCal
® Stabilized
Formazin.
A dry verification directly after calibration is used to establish the baseline. Any verification
afterwards, until the next calibration, that uses the same dry verification standard will
reference the recorded value from the baseline verification as the “expected” value. In
order for the verification to pass, the measured value should be within the limits set by the
Pass/Fail Criteria of the baseline value.
5.5.3.1 Dry Verification
1. From the Main Menu, select SENSOR SETUP and confirm.
2. Select CALIBRATE and confirm.
3. Select VERIFICATION and confirm.
4. Select PERFORM VER and confirm. Select the available Output Mode (Active, Hold,
or Transfer) from the list box and confirm.
5. Select DRY for the verification type and confirm.
6. Select 1 NTU STD or 20 NTU STD or verify SN of previously used calibration device
and confirm.
7. Set the Head to Standard and confirm. Confirm again to accept the reading.
8. The display will read GOOD VER!. Confirm.
9. Enter initials and confirm.
10. Return the sensor to measure mode and confirm.
5.5.3.2 Wet Verification
Before starting the verification, read and apply the appropriate tips in section 5.6 . For wet
verification values at or below 1.0 NTU, only use the cleaned turbidimeter body.
1. From the Main Menu, select SENSOR SETUP and confirm.
2. Select CALIBRATE and confirm.
3. Select VERIFICATION and confirm.