Appendix D

1.Determine the flow increment between samples:

Q 85,000 gallons

f = ---- = --------------------------------------= 3,542 gallons/sample

n 24 samples

2. Multiply the flow increment, f, by the pulse frequency output of the flow meter.

3,542 gallons/sample

-----1-----pulse-----------------

= 70.84 pulse/sample

 

50 gallons

 

Therefore, the value for INTV = _ _ _ _ CNTS is 71.

Example 3

You want to collect 48 samples over a 16-hour period. The total expected flow over this period is 1,750,000 gallons. The flow meter pulse frequency output is one pulse for every 1,000 gallons.

1.Determine the flow increment between samples:

Q 1,750,000 gallons

f = ---- = ----------------------------------------------= 36,458 gallons/sample

n 48 samples

2. Multiply the flow increment, f, by the pulse frequency output of the flow meter.

36,458 gallons/sample

1 pulse

= 36.458 pulses/sample

1,000-----------------gallons------------------

Therefore, the value for INTV = _ _ _ _ CNTS is 36.

Flow Proportional Sampling, External—Using 4–20 mA Signal Converted to Pulses, Flow Signal Interface The Flow Signal Interface (Cat. No. 2021) is an optional 4–20 mA interface that converts 4–20 mA current signals (from a flow meter) to 12 V dc pulses.

At 20 mA, the interface transmits 10 12-volt pulses per minute. As the current signal decreases, the 12 V pulses decrease proportionally. Typically, users collect a certain number of samples over a given period of time when sampling in proportion to the flow rate.

To calculate the number of 12 V dc output pulses between samples, determine the total number of samples (represented by n in the following examples) that you want to collect, and the period of time over which you want to collect them. Use the three-step method presented below to determine the “Total Count” value that you will enter while programming the Setup section of the sampler.

1.Calculate Q, where Q is the average flow rate (during the sampling program) divided by the maximum flow rate. (The maximum flow rate corresponds to the 20 mA output of the flow meter.)

2.Calculate t, where t is defined as a/n; n is the total number of samples collected over a given period of time; and a represents time in minutes, over which n samples are collected.

3.Multiply Q x t x 10. Enter the result in the programming step:

INTV = _ _ _ _ CNTS.

Note: The product of Q x t x 10 is not necessarily a whole number. You must round off the result to the nearest whole number.

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How to Calculate Pulses/Counts

8990apdx_pulsecounts.fm

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Hach 900 MAX manual Appendix D, Intv = Cnts How to Calculate Pulses/Counts

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.

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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.

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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.

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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.