Hach 900 MAX Instrument Manual page 49

Step 7 - Liquid Sensor
Note: Sample retries cannot be
enabled when the liquid sensor
is disabled.
8990startup.fm
b. If Stop After Last Sample is chosen, enter the samples to collect
using the numeric keypad. Press
Liquid Sensor.
11:00 AM 21 - APR - 01
ACCEPT
SAMPLES TO COLLECT:
BACKUP
ENTER: 1 — 999
Example 1: The following example creates four identical composite
samples automatically if the sampler is programmed as follows:
• Bottles— 4
• Sample Collection; Sampling Interval— 30 minutes
• Sample Collection; Samples to Collect— 25
• Sample Volume— 100 mL
Every 30 minutes a sample is initiated and a 100 mL sample is drawn into
the first bottle. The distributor arm advances to bottle #2 and 100 mL of
sample is drawn into the second. This also occurs in bottles #3 and #4.
Sampling will continue every 30 minutes until 25 samples are deposited.
Once all samples are deposited the program will terminate. If Run
Continuously is selected the sampling will restart automatically.
The liquid sensor contains a pair of ultrasonic transducers which sense the
presence of liquid inside silicone tubing.
7-A. Enable or Disable Liquid Sensor using the
Enabling the Liquid Sensor
When the liquid sensor is enabled, the sampler will perform two duties:
• It senses when liquid reaches the pump during an intake cycle. The pump
then reverses to rinse the line, up to three times.
• It senses the absence of liquid during a sample intake cycle if the intake
tubing is plugged or if the water level has dropped below the level of the
intake tube strainer. This initiates a Sample Retry if programmed
Disabling the Liquid Sensor/Timed Calibration
Disabling the liquid sensor turns the liquid sensor off. The sample volume is
then metered using a timed method (Timed Calibration), instead of a
sensed method.
7-B. Press to continue to Sample Volume.
ACCEPT
Section 3
to continue to
ACCEPT
SAMPLE DISTRIBUTION
2 CLEAR
ENTRY
CHANGE CHOICE
Basic Programming Setup
key.
Page 47