Grab Sample Measurement Cycle - Hach polymetron 9240 User Manual

4. Phase 4: The overflow vessel is drained, and the system waits for the operator to fill the
overflow vessel with the low value calibration solution.
5. Phase 5: The overflow vessel is drained into the measurement cell and the first
concentration measured.
6. Phase 6: The overflow vessel is rinsed and then drained. The system waits for the operator
to fill the overflow vessel with the high value calibration solution.
7. Phase 7: The overflow vessel is drained into the measurement cell and the second
concentration measured.
8. Phase 8: The slope and offset are calculated and displayed. If the calculated slope and
offset values are within the acceptable limits they will be used for all future measurements.
Normal measurement is then resumed starting with a smart or fixed rinsing step.

3.9 Grab sample measurement cycle

The following section gives an overview of the grab sample measurement process. For details
on setting up and running this process, refer to the section entitled
The measurement cycle is as follows:
1. Phase 1: The electrode is reactivated. This consists of injecting Sodium Nitrate into the
solution to maintain a high level of sodium measurement for a minimum of 5 minutes (this
step can be skipped if time is more important than accuracy).
2. Phase 2: When reactivation has completed, the measurement cell is rinsed for 10 minutes
or, if the reactivation has been skipped then the overflow vessel is emptied and refilled with
the sample used for calibration.
3. Phase 3: The overflow vessel is drained, and the system waits for the operator to fill the
overflow vessel with the grab sample.
4. Phase 4: The overflow vessel is drained into the measurement cell and the sample
concentration measured.
5. Phase 5: The measurement value is displayed. Normal measurement is then resumed
starting with a smart or fixed rinsing step.
Figure 12 Grab sample measurement cycle
Analyzer Overview
Grab sample on page 69.
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