Hach-Lange SIGMA SD900 Refrigerated Sampler and All Weather Refrigerated Sampler User Manual - Manual (Page 61)

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Sampler operation
4.9.1 Liquid sensor calibration
The accuracy of the liquid sensor can vary with the type of liquid
that is being sampled. For example, the volume of a highly turbid
sample may not be as accurate as that of clear water. In some
applications, the liquid sensor may be calibrated using the source
liquid to improve detector performance.
Procedure:
1. Make sure the liquid sensor is enabled by selecting PROGRAM
SETUP > MODIFY SELECTED > LIQUID SENSOR > ENABLE .
2. Select SYSTEM SETUP > LIQ SENSOR CAL from the main menu.
3. Select PERFORM CAL .
4. Place the intake tube into the sample source or tap water (if tap
water is representative of the type of samples to be collected).
Note: Use the sample source for best accuracy.
5. Select START . The pump will operate in reverse to purge the
intake tube.
6. The pump will then operate in the forward direction. Observe
the sample flow in the intake tube to verify that it passes the
liquid sensor. When the sample passes through the liquid
sensor and no bubbles are present, press the
STOP key.
7. The liquid sensor calibration is complete after the intake tube is
automatically purged. Select DONE to exit the liquid sensor
menu or REPEAT to repeat the calibration.
Note: To restore the default calibration for the liquid sensor, select
SYSTEM SETUP>LIQ SENSOR CAL>RESTORE DEFAULT from the
main menu.
4.9.2 Set the thermal setpoint (AWRS only)
The setpoint is the temperature that will be maintained inside the
refrigerated compartment. The EPA recommends that the samples
be stored at 4 °C, which is the default setpoint.
Procedure:
1. Select SYSTEM SETUP>THERMAL SETUP from the main menu.
2. Select SETPOINT .
3. Enter the setpoint in °C and press ENTER . The setpoint can be
a value between 2 and 10 °C.
4.9.3 Set password
A password can be enabled to restrict access to the program setup
and system setup menus.
Procedure:
1. Select SYSTEM SETUP > PASSWORD SETUP from the main
menu.
2. Select ENABLE to activate a password.