Step 9 - intake rinses, Step 10 - sample retries – Hach 900 MAX User Manual

Page 50

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Page 48
Basic Programming Setup

8990startup.fm

Section 3

Step 8 - Sample Volume

Note: The minimum sample volume
is ten milliliters.

When multiple bottles are selected in Bottle Per Sample mode all bottles in a
subset receive a full sample volume. The volume is not divided among
the bottles.

8-A. Enter the desired volume of each sample using the numeric keypad.

Press

ACCEPT

to continue to Intake Rinses.

Step 9 - Intake Rinses

9-A. Enter number of rinses using the numeric keypad.Press

ACCEPT

to

continue to Sample Retries.

Up to three intake rinses are enabled per sample cycle. After the sample
cycle’s initial purge has been completed, the sample liquid is drawn in until it
reaches the liquid sensor. The pump stops and purges the line before any
liquid enters the bottle. This is repeated up to three times before the actual
sample is taken and the line purged for the final time during that cycle.

Intake rinse can prevent cross contamination of samples. When the line is
purged at the end of each sample cycle, a few droplets of sample liquid may
cling to the inside walls of the tubing and the droplets are drawn in with the
following sample. Intake rinses will condition the intake line with a source
liquid that minimizes contamination from the previous sample.

Step 10 - Sample Retries

Note: Excessive intake tube line
lengths combined with multiple
Intake Rinses and Sample Retries
can increase the pump tube and
drive train wear. Locate the sampler
as close to the sample liquid source
as possible to minimize wear and
maintenance requirements.

10-A. Enter the number of Sample Retries using the numeric keypad. Press

ACCEPT

to continue to Site ID.

Up to three sample retries are enabled per sample cycle. After the initial purge
is completed, the sample liquid is drawn until it reaches the liquid sensor. If
the sample liquid does not reach the sensor within a reasonable time
(determined using the tubing length), the sample attempt is aborted, a purge
is initiated and the first of up to three sample retries is attempted.

After three attempts and no sample liquid has been collected, the cycle is
aborted, a Missed Sample is reported to the Sample History Log, and the
sampler begins a new sample interval.

11:00 AM 21 - APR - 01

SAMPLE VOLUME

ACCEPT

SAMPLES VOLUME:

BACKUP

______

CLEAR

ENTRY

ENTER: 10 — 9999

11:00 AM 21 - APR - 01

INTAKE RINSES

ACCEPT

INTAKE RINSES:

BACKUP

0

CLEAR

ENTRY

ENTER: 0 — 3

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