HF scientific Micro1000 Laboratory Turbidimeter - 0-10,000 NTU - Manual (Page 14)

Rev. 3.2 8
4.5. Dry Air Purge System
Cold samples, or the continuous flow of cool water through the flow-through cuvette may cause
condensation on the walls of the cuvette. This condensation can cause faulty and erratic readings
with the instrument. To eliminate this effect, a built in dry air purge system has been designed to
optimally circulate air through the optical compartment and prevent this condensation. This is a
particularly important feature when using either the pour through or the flow through option.
To use, connect the regulated dry air source to the air purge fitting on the rear panel of the
instrument. The fitting is designed for use with 1/8” I.D. flexible tubing. Allow air to flow as long
as needed to control condensation; dry nitrogen or instrument grade air up to 15 PSIG (103.5 kPa)
should be used at flow rates between 2 – 7 SCFH. Once installed allow the system approximately 15
minutes to evacuate the chamber before proceeding with your measurements.
4.6. Using the Security Access Feature (Good Manufacturing Practice [GMP])
The instrument is equipped with a security feature that can be turned on, or off, when configuring
the instrument. Two access codes are used in the instrument and configurable by the user (see
section 8.3). The access code is required as an input whenever the user wishes to gain access to
either the calibration routine or the configuration (setup) routine when the feature is enabled. Use
either the S or keysT to select the mode that you wish to enter and then press the key. If the
security code option is turned on you will see the following display:
This security code has four numbers that are selectable one at a time. The number that is flashing is
the first number for you to select. Use either the S or T keys to select this number in the code then
press the key to move to the next number. Follow this process through the four numbers in the
access code. If you have selected a valid access code, the instrument will be directed to either the
calibration or the configuration (user setup) mode depending on your original intention. If the wrong
access code is selected, the instrument will return to the normal automatic mode.
5. Calibration Procedures
The instrument was calibrated and tested prior to leaving the factory using calibration standards that
are traceable to the primary turbidity calibration standard, Formazin. Therefore, it is possible to use
the instrument directly out of the box. However, re-calibration of the instrument is recommended to
help you become familiar with the operation of the instrument and the calibration procedures.