Hanna Instruments HI 95721 - Manual (Page 10)

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The flashing digits indicate that:
1) the month can be set
2) the day can be set
“Storage”: this prompt appears for 1 second at the end of the
calibration procedure, to indicate that the calibration data has
been stored.
“Error”: the concentration of the calibration solution used is not correct.
Repeat the calibration procedure with the right standard solution, and
verify it is not expired. If the calibration procedure fails again, contact your
dealer or the nearest Hanna Customer Service Center.
ERROR MESSAGES
a) on zero reading
This indicates that the zeroing procedure failed due to a low signal-to-
noise ratio. In this case press ZERO again.
“No Light”: the instrument cannot adjust the light level. Please check that
the sample does not contain any debris.
“Light Low”: there is not enough light to perform a measurement. Please
check the preparation of the zero cuvet.
“Light High”: there is too much light to perform a measurement. Please
check the preparation of the zero cuvet.
b) on sample reading
There is too much light for the sample measurement. Please check if the
right sample cuvet is inserted.
“Inverted”: the sample and the zero cuvet are inverted.
“Zero”: a zero reading was not taken. Follow the instruction in the
measurement procedure for zeroing the meter.
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Under range. A blinking "0.00" indicates that the sample absorbs
less light than the zero reference. Check the procedure and make
sure you use the same cuvet for reference (zero) and measurement.
A flashing value of the maximum concentration indicates an over
range condition. The concentration of the sample is beyond the
programmed range: dilute the sample and re-run the test.
A flashing value lower than the maximum concentration indicates a
low signal-to-noise ratio condition. In this case accuracy of the result
is not guaranteed. Repeat the measurement procedure.
The instructions listed below should be carefully followed during testing to ensure best accuracy.
• Filter sample after collection and before testing, if only
dissolved iron has to be measured.
• For a correct filling of the cuvet: the liquid in the cuvet
forms a convexity on the top; the bottom of this convexity
must be at the same level of the 10 mL mark.
• Proper use of the powder reagent packet:
(a) use scissors to open the powder packet;
(b) push the edges of the packet to form a spout;
(c) pour out the content of the packet.
(a) (b) (c)
GENERAL TIPS FOR AN ACCURATE MEASUREMENT