Appendix B

LCD Test

Display Test allows you to verify that all pixels in the Liquid Crystal Display (LCD) are functional. The LCD is made up of 14,400 pixels that are turned on and off as needed to create the display of graphics and text. Each individual pixel is turned on and off by its own transistor, which means that if a transistor failed, the pixel might not turn on, which could cause an unreadable or confusing display.

Selecting LCD Test from the Diagnostics menu will cause the display to become black for 3 seconds. This allows verification that all pixels are functional. A defective pixel will stand out as a white dot in the field of black dots. A message, “The display will remain inverted for 3 seconds” is shown for 2 seconds followed by a 3 second period with all dots turned on.

Liquid Sensor

The liquid sensor contains a high frequency sound transmitter and receiver. High frequency sound waves are sent through the silicone pump tubing by vibrating a piezo-electric crystal. They are picked up on the other side of the tubing by a receiving crystal acting much like a microphone. Since sound waves travel much more efficiently through a liquid than they do through air, the receiving crystal gets a much louder signal when water passes through the tubing in the sensor. The signal from the receiving crystal is converted to a voltage which is proportional to the signal strength. This voltage is used by the sampler microprocessor to sense the exact moment water reaches the sensor. the liquid sensor compares the voltage (signal strength) when the tubing is dry (such as when purging the line) to the voltage when the tubing is full of water (such as when pumping a sample). The dry verses wet voltage reading must be at least 0.8 V dc higher than the 0.3 volts, then when the voltage needed to sense liquid would be 1.1 volts or higher.

The Liquid Sensor is designated as #1. The diagnostic screen displays the voltage coming from the sensor electronics. Should a problem arise where the liquid sensor is not reliably sensing the liquid, (inaccurate sample volumes, water getting to the bottle during an intake rinse, purge failure), use of the Liquid Sensor diagnostics values will provide valuable information as to the sensor sensitivity.

Velocity Analysis

A velocity probe must be installed in the flow stream and be connected to the meter in order for this diagnostic to work. This diagnostic allows viewing a ‘real time’ reading directly from the Submerged Area Velocity Probe. It will show the current velocity Signal Strength (percentage of Doppler signal returning to the probe) and a ‘real time’ velocity measurement of the flow stream. Use this diagnostic to determine if the probe is mounted for optimal velocity measurement. The closer to 100% the Signal Strength is, the more stable the velocity reading will be. If the signal seems low (50% or less), it may be due to improper installation of the probe or a lack of particulate in the flow stream.

11:00 AM 21 - APR - 01

VELOCITY ANALYSIS

SIGNAL STRENGTH: 90‰

VELOCITY: 7.00 fps

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Programming Features

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Hach 900 MAX manual Velocity Analysis, Velocity 7.00 fps
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900 MAX specifications

The Hach 900 MAX is an advanced analytical instrument designed to perform water quality analysis with precision and efficiency. This multiparameter water quality analyzer is tailored for a wide range of applications, including environmental monitoring, wastewater treatment, and industrial processes. Its unique design and technology make it a valuable tool for professionals in the field.

One of the standout features of the Hach 900 MAX is its ability to measure multiple parameters simultaneously. Equipped with advanced sensors, the device can analyze key water quality indicators such as pH, turbidity, dissolved oxygen, conductivity, and various chemical parameters. This comprehensive measurement capability allows users to gain a complete understanding of water quality in a single run, saving both time and resources.

The Hach 900 MAX utilizes cutting-edge technologies to provide accurate and reliable results. Its integrated optical sensors employ advanced photometry, which enhances the detection of chemicals in water samples with high sensitivity. Additionally, the device includes advanced calibration management tools that ensure consistent accuracy over time. Users can easily perform routine calibrations with minimal effort, facilitating reliable data collection.

Another notable characteristic of the Hach 900 MAX is its user-friendly interface. The instrument features a large, touchscreen display that allows for intuitive navigation through various settings and parameters. Users can quickly access real-time data, generate reports, and analyze trends using the built-in software. The ability to customize dashboards and create visual representations of data enhances user experience and simplifies the decision-making process.

In addition to its analytical capabilities, the Hach 900 MAX emphasizes connectivity and data management. The instrument can be connected to laboratory information management systems (LIMS) and other data networks, enabling smooth data transfer and integration into existing workflows. This connectivity enhances collaboration among team members and facilitates compliance with regulatory requirements.

Durability is another hallmark of the Hach 900 MAX. The device is designed for use in demanding environments, with robust construction and protection against dust and moisture. This reliability ensures that the analyzer remains operational even in challenging conditions, making it suitable for field applications.

Overall, the Hach 900 MAX stands out as a powerful and versatile tool in the realm of water quality analysis. With its multiparameter measurement capabilities, advanced sensor technologies, user-friendly interface, and reliable performance, it enables professionals to obtain accurate insights into water quality efficiently. As environmental concerns continue to grow, instruments like the Hach 900 MAX play a crucial role in ensuring the safety and sustainability of water resources.
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