Hach-Lange 2100 N Laboratory Turbidimeter User Manual - Manual (Page 13)

5. Push the power switch on the back of the instrument to turn the
instrument on.
Turn the keypad sound off (optional)
By default, the instrument makes an audible sound when a key is
pushed. To turn the keypad sound off:
1. Push and hold down the right arrow key for 3 seconds.
2. Use the arrow keys to select 00.
3. Push ENTER.
4. Use the arrow keys to select the sound option:
Option Description
bP on An audible sound is made when a key is pushed.
bP oF No sound is made when a key is pushed.
5. Push ENTER.
Standard operation
Calibrate the turbidimeter with StablCal ® Standards
Calibrate the turbidimeter before it is used for the first time using the
StablCal
® sealed vial standards provided. As an alternative, calibration
can be done with recently prepared formazin standards. Refer to
Calibrate the turbidimeter with formazin standards on page 32.
Calibrate the turbidimeter at least every 3 months or as specified by the
regulating authority when data is used for USEPA reporting.
The instrument is ready for calibration 60 minutes after start-up. Keep
the instrument on 24 hours a day if the instrument is used regularly.
Note: Unknown results may occur if standards other than the recommended
calibration points are used. The recommended calibration points (< 0.1, 20, 200,
1000 and 4000 NTU) provide the best calibration accuracy. Use of standards other
than StablCal, or user-prepared formazin, may result in less accurate calibrations.
The manufacturer cannot guarantee the performance of the instrument if calibrated
with co-polymer styrenedivinylbenzene beads or other suspensions.
Prepare the StablCal standards
When received and at intervals:
1. Clean the exterior surface of the StablCal vials with laboratory glass
cleaning detergent.
2. Rinse the vials with distilled or deionized water.
3. Dry the vials with a lint-free cloth.
Note: Never shake or invert the < 0.1 NTU standard. If the standard has been
mixed or shaken, do not move the vial for 15 minutes or more before using.
Note: Do not remove the caps from the sealed vials.
Make sure that the StablCal standards are at ambient instrument
temperature before use (and no greater than 40 °C (104 °F)).
Mix the standards before use:
1. Open the case lid. Remove the < 0.1 NTU standard from the plastic
case.
2. Leave the other standards in the case. Close the case lid.
3. Shake the case vigorously for at least 10 seconds.
4. Let the standards stand with no movement for 3–5 minutes before
use.
Calibration notes
• Make sure that the instrument is in the same ambient conditions as
where it is used.
• Make sure that the standards are at the same ambient temperature as
the instrument before use.
• Use only the provided silicone oil. This silicone oil has the same
refractive index as the vial glass and masks minor glass differences
and scratches.
• Store the oiling cloth in a plastic storage bag to keep the cloth clean.
• If power is lost during calibration, the new calibration data is lost and
the last calibration data is used. To exit a calibration and not save the
new values, push UNITS/Exit.
• In Calibration mode, automatic range and signal averaging on are
selected. When calibration is completed, all operational modes go
back to the last settings.
English 11