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How to Calculate Totalized Dissolved Oxygen (DO) Based on DO Probe Readings and Flow Meter Measurements

Question:

Hello everyone, I am looking for an STL code that can calculate the totalized dissolved oxygen (DO) value based on the readings from a DO probe taken every 5 seconds. The volume of liquid passing through the transfer line in each 5-second interval preceding a DO reading must be measured by a flow meter. The totalized DO value is calculated by summing the product of the DO value and the volume in each 5-second interval. The totalized volume is the sum of all volumes in each 5-second interval. The integrated DO value is then obtained by dividing the totalized DO value by the totalized volume.

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Do you know what a PLC is? Can you tell us the brand and model number of the sensor you are using? Is the sensor compatible with I/O, 0-10 volt, 1-5 volt, or 4-20mA? What is the flow rate of the sensor? These are important questions to consider. Share your progress with us and we will happily assist you, but we won't do your work or homework for you. Thank you, James.

Are you asking about the calculation for Integrated Dissolved Oxygen (DO) value over a specific period of time, given by the formula ΣNi=1(DOi* VOLUMEi) / ΣNi=1VOLUMEi, where N represents a series of 5s intervals from a certain point in the past up to the present?

The Siemens PLC is programmed using the popular software, Simatic Manager. However, I am encountering some issues that need to be addressed: 1. The timer functionality appears to be malfunctioning. 2. The initial and final readings from the flow meter are consistently displaying the same values, making it impossible to calculate volume accurately within the 5-second timeframe. I have included my logic for review and debugging. Thank you for your assistance.

Ensure you include the full source code for both the function and function block. The interface section for the function is not included, and the closing statement for the function block is also missing.

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Frequently Asked Questions (FAQ)

FAQ: 1. How can I calculate totalized dissolved oxygen (DO) based on DO probe readings and flow meter measurements?

Answer: - To calculate the totalized DO value, you need to sum the product of the DO value and volume in each 5-second interval, then divide this total by the sum of all volumes in each 5-second interval.

FAQ: 2. What is the significance of measuring the volume of liquid passing through the transfer line in each 5-second interval?

Answer: - Measuring the volume is essential for accurately calculating the totalized DO value, as it allows for the proper integration of DO readings with the corresponding liquid flow.

FAQ: 3. How frequently should the DO probe readings and flow meter measurements be taken?

Answer: - The DO probe readings should be taken every 5 seconds, along with measuring the volume of liquid passing through the transfer line in the same intervals for accurate calculations.

FAQ: 4. Is there a specific formula or code to calculate the totalized dissolved oxygen value?

Answer: - While there may not be a standard formula, you can achieve the calculation using a code that sums the products of DO values and volumes in each 5-second interval, then divides by the total volume to obtain the integrated DO value.

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