Hach-Lange 1720E Low Range Turbidimeter - Manual (Page 22)

18
Operation
5.5 Sensor Calibration and Verification
The manufacturer offers two EPA-approved calibration methods one using user-prepared
formazin and the other using StablCal
® Stabilized Formazin. Two verification methods
(wet and dry) are also offered.
The 1720E Turbidimeter is factory-calibrated using StablCal Stabilized Formazin before
shipment. The instrument must be recalibrated before use to meet published
accuracy specifications. In addition, recalibration is recommended after any significant
maintenance or repair and at least once every three months during normal operation. The
turbidimeter body and bubble trap must be thoroughly cleaned and rinsed before
initial use and prior to each calibration.
Tips to achieve the most accurate calibrations:
• Optimum performance is achieved when calibration is performed in the turbidimeter
body. Accurately prepare the standard then add it to the turbidimeter body at the
appropriate step in the procedure. Do not prepare the standard in the body.
5.4 Sensor Setup Menu
SELECT SENSOR (if more than one sensor is attached)
CALIBRATE
USER PREPD CAL Calibration using 4000 NTU stock solution diluted to 20.00 NTU formazin.
STABLCAL CAL Calibration using 20 NTU StablCal Stabilized Formazin Standard
VERIFICATION Perform a verification, set the pass/fail criteria, and view the verification history.
0 ELECTRONICS Zero electronics
CAL HISTORY
View the last 12 entered calibrations. Confirm to move to the next history entry. See section 5.6
on page 22 for more information.
CONFIGURE
BUBBLE REJECT Choose Yes or No to enable/disable bubble reject. Default: Yes
SIGNAL AVG
Choose no averaging or specify the amount of time for signal averaging. Available options are:
no averaging, 6 sec., 30 sec., 60 sec., or 90 sec. Default is 30 seconds.
MEAS UNITS
Select the appropriate measurement units to display. Choose from mg/L, NTU, TE/F, FTU and
Degree. Default: NTU
EDIT NAME
Enter up to a 12-digit name in any combination of symbols and alpha or numeric characters.
Confirm when the entry is complete. The name will be displayed on the status line above the
measurement value on the main display.
SET RESOLUTION Set the number of significant digits to display. Default is three significant digits.
DATALOG INTRVL
Choose the amount of time between saving data points to the data log. Default: 15 min.;
Options: 30 sec., 1 minute, 5 minutes, 10 minutes, or 15 minutes.
OFFSET Enter an offset between –0.05 to 0.05 NTU. Values outside this range are not accepted.
DIAG/TEST
SOFTWARE VERS. Displays the software version number.
SERIAL NUMBER Displays the serial number of the sensor.
INT TEMP Displays the internal temperature of the sensor electronics in °C.
DEFAULT SETUP Restores the sensor’s factory default settings and invalidates the current calibration.
POWER CHECK Displays the electrical statistics for the sensor.
SERVICE MODE Choose On or Off to enable/disable service mode. Default: Off
SERVICE DIAGS Passcode protected. Menu options only available to service personnel.