Data Logging; Calibration Procedure - Hach FT660 sc Basic User Manual

Option Description
DATALOG Select the interval between saving data points to the
INTRVL data log—30 seconds or 1, 5, 10 or 15 (default) minutes.
OFFSET Sets an offset of the value of the standard used for
calibration (-50 to +50 mNTU, default=0).
The offset value is subtracted from the calibration
standard value shown on the sc controller.
The offset can be entered after a calibration is complete
and is based on independent turbidity measurement of
the calibration standard.
Note: The offset will not result in a calibration standard
value of less than zero on the sc controller.

Data logging

The sc controller provides one data log and one event log for each
instrument. The data log stores the measurement data at selected
intervals. The event log stores different types of events that occur on the
devices (i.e., configuration changes, alarms and warning conditions).
The data log and the event log can be saved in CSV format. Refer to the
sc controller user manual for instructions.
Calibration
Calibration is done in the body of the instrument or using the optional
calibration kit.
Calibration is done using 1 L of 800 ± 50 mNTU StablCal Stabilized
Formazin Certified Standard. Do not use other types or values of
standards. Do not use user-prepared formazin.
The performance specifications given in this manual are based on and
guaranteed only when calibration is done with StablCal Stabilized
Formazin Certified Standard for this instrument. The manufacturer
cannot guarantee the performance of the instrument if calibrated with co-
polymer styrenedivinylbenzene beads or other suspensions.
®
Prepare the StablCal Standard
• Before opening a StablCal Standard bottle, clean the exterior surface
of the bottle with clean water to remove dust or other debris.
10 English
• Gently invert the bottle for 1 minute (about 50 inversions). Do not
shake.
Note: The suspension is stable for 30–60 minutes after mixing.
The StablCal Certified Standard is stabilized formazin with a value that is
identified to within ± 1 mNTU. The value, specific to that particular lot of
product, is printed on the label. Lot-to-lot variation will be ± 50 mNTU
from the standard value, with a standard deviation of less than ± 5%
within a single lot.
Calibration notes
• Calibrate the instrument before initial use.
• Calibrate the instrument every three months (or as set by regulatory
agencies).
• Calibrate the instrument after any significant maintenance or repair is
done on the instrument.
• Always clean the instrument immediately before calibration. Refer to
Clean the instrument on page 17.
• Operate the instrument at least 10 hours before calibration.
• For the best calibration, calibrate the instrument when it is at the same
temperature as the operating conditions.
• The Hold Outputs feature is automatically enabled during the zero
electronics and calibration procedure. The Hold Output feature holds
attached outputs at the before-calibration settings.

Calibration procedure

1. From the Main menu, select Sensor Setup, [Select Sensor],
Calibrate, StablCal Cal.
2. Select the available Output Mode (Active, Hold or Transfer) from the
list box and confirm.
3. Remove the head assembly and bubble trap cover from the body of
the instrument. Refer to Figure
4. Make sure that the body of the instrument is drained completely.
5. Enter the turbidity value that is on the label of the StablCal Standard
bottle and confirm.
6. Put a funnel at the end of the bubble trap and slowly put 800 mNTU
StablCal Standard in the funnel to fill the body. Refer to
7.
Figure 7.