Setting The Analyzer Mode; Grab Mode Measurement Settings - GE Sievers 900 Series Operation And Maintenance Manual

Setting the Analyzer Mode

The Sievers 900 On-Line TOC Analyzer can operate in two different modes. To set the Analyzer
mode, follow these steps:
1. Select the Setup tab (see Figure 12).
• Select On-Line to measure TOC continuously from a sample stream or sipper tube. If a
sipper tube is used, the Flow Sensor must be disabled; see "Configuring the Flow
Sensor" on page 118 for details. On-Line is the default mode for the Sievers 900 On-
Line Analyzer.
• Select Grab to measure TOC directly from a sample flask using the sipper tube
attachment or the vial port. After you select Grab, you will need to press the Configure
Mode button to configure the settings for Grab mode. If you will be sampling from a
flask, you will also need to change the sample inlet configuration.

Grab Mode Measurement Settings

When selecting Grab mode, you need to specify the number of replicate measurements and rejects
as follows:
1. On the Setup tab, press the Configure Mode button.
2. Press the Reps button to set the number of replicate TOC measurements to be made on
the sample. When you press the button, a number pad displays. Enter a number and press
the Enter button to save the value, or press Cancel to retain the current setting without
making any changes.
3. Press the Rejects button. This option determines how many of the replicate measurements
will be rejected in calculating average values and standard deviations. When you press the
button, a number pad displays. Enter a number and press the Enter button to save the
value, or press Cancel to retain the current setting without making any changes.
4. Press the Grab Label button to assign an alphanumeric label of up to 7 characters to each
grab sample. The label displays in the data history. After the analysis completes, the Grab
Label resets to its default value.
In most cases, this first measurement will be close to the actual TOC but may be outside of the
repeatability of the Analyzer. It is best to set the number of rejections to 1 or more to ensure an
accurate TOC value. Using at least 4 repetitions allows rejection of the first value and calculation of
a standard deviation using the remaining values.
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