Hach DR300 User Manual page 17

There are two options to enter a user calibration curve:
• Enter a calibration curve with standards—The standard solution
values are entered with the keypad and the absorbance values are
measured.
• Enter a calibration curve with the keypad—The standard solution
values and absorbance values are entered with the keypad.
Note: If the instrument is set to off or the instrument power is removed before a
user-entered calibration curve is completed, the calibration curve is not saved.
The instrument automatically switches off in user-entered calibration entry mode
after 60 minutes of no activity. User-entered calibrations are completed when the
user goes out of calibration (cal) mode or edit mode.
Enter a calibration curve with standards
Chemical exposure hazard. Obey laboratory safety procedures and
wear all of the personal protective equipment appropriate to the
chemicals that are handled. Refer to the current safety data sheets
(MSDS/SDS) for safety protocols.
Chemical exposure hazard. Dispose of chemicals and wastes in
accordance with local, regional and national regulations.
Note: As an alternative, deionized water can be used for the blank unless the
sample is significantly more turbid or has more color than deionized water.
1. Push to set the instrument to the range to calibrate (e.g., LR or
HR).
2. Prepare the blank. Refer to the test procedure.
3. Clean the sample cell with a no-lint cloth.
4. Set the instrument to zero.
a. Insert the blank sample cell in the cell holder.
b. Install the instrument cap over the cell holder.
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