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I/O & Calculation Analog Tags

Our SCADA is pulling analog I/O from a InSiteIG instrument for dissolved oxygen and total suspended solids. It is pulling modbus addresses; for example, register 30005 would be the sensor value for D.O. sensor 1. I am looking to improve on the basics of what has already been designed by using the I/O & Calculations, Analog (Calculation box ticked). I'm having somewhat of a difficult time in configuring such a tag. The way I currently have it is I created an analog status tag that looks at address 30005. It pulls up a whole value, but I want it to be displayed as a decimal. I had to create a calculation tag where the expression looks at the analog status tag then divides that by 100. After creating those two tags I created an analog status widget in which it is set to look at the analog status calculation tag and display that decimal value for the operators to see. My ultimate goal is to have only one created tag that both looks at the address for data then takes that value and divides it by a certain number. I then want to point that calculated value to an analog status widget. How do I create such a tag to do all of that.

Our SCADA is pulling analog I/O from a InSiteIG instrument for dissolved oxygen and total suspended solids. It is pulling modbus addresses; for example, register 30005 would be the sensor value for D.O. sensor 1. I am looking to improve on the basics of what has already been designed by using the I/O & Calculations, Analog (Calculation box ticked). I'm having somewhat of a difficult time in configuring such a tag. The way I currently have it is I created an analog status tag that looks at address 30005. It pulls up a whole value, but I want it to be displayed as a decimal. I had to create a calculation tag where the expression looks at the analog status tag then divides that by 100. After creating those two tags I created an analog status widget in which it is set to look at the analog status calculation tag and display that decimal value for the operators to see. My ultimate goal is to have only one created tag that both looks at the address for data then takes that value and divides it by a certain number. I then want to point that calculated value to an analog status widget. How do I create such a tag to do all of that.

Electronics/Electrical Technician
Hilliard Fletcher Wastewater Treatment Plant

I wanted to provide an update, so I was able to "kind" of get it working in the manner I would like. However, I still have some questions. I know I can create a tag that looks at some device or instrument and pull that data to SCADA. The one thing I do not know is how I can use one tag that will look for IO then give you the ability to calculate a value. When SCADA polls the InsiteIG device it only pulls in a whole value rather than a decimal value. I want the operators to see that aeration basin, anoxic zone sensor is .20 ppm instead of 20. I know of only one way and that's creating an analog status tag that reads a value from the device. I then have to create a child calculation tag where the expression is looking at the parent then dividing by 100.

685d4c19a3e9a
685d4c248952c

I wanted to provide an update, so I was able to "kind" of get it working in the manner I would like. However, I still have some questions. I know I can create a tag that looks at some device or instrument and pull that data to SCADA. The one thing I do not know is how I can use one tag that will look for IO then give you the ability to calculate a value. When SCADA polls the InsiteIG device it only pulls in a whole value rather than a decimal value. I want the operators to see that aeration basin, anoxic zone sensor is .20 ppm instead of 20. I know of only one way and that's creating an analog status tag that reads a value from the device. I then have to create a child calculation tag where the expression is looking at the parent then dividing by 100. ![685d4c19a3e9a](serve/attachment&path=685d4c19a3e9a) ![685d4c248952c](serve/attachment&path=685d4c248952c)

Electronics/Electrical Technician
Hilliard Fletcher Wastewater Treatment Plant

That's what the scaling tab is for.

Put your raw value range in the "Unscaled Process Data" fields, and your engineering scale in The "Scaled Process Data" fields.

Unscaled Process Data Min = 0,
Unscaled Process Data Max = 100,
Scaled Process Data Min = 0,
Scaled Process Data Max = 1

Given those parameters, a raw value of 20 will be converted to .2

You can define how many digits to display under the "Display" tab.

If you need to do more than scale, like add an offset or something, you'll need to continue to use the calculation mode.

edit to add: After you scale, check that the input deadband on the I/O tab still makes sense. It auto-calculates based on scaling by default, but if you've modified it then it may need to be adjusted.

That's what the scaling tab is for. Put your raw value range in the "Unscaled Process Data" fields, and your engineering scale in The "Scaled Process Data" fields. Unscaled Process Data Min = 0, Unscaled Process Data Max = 100, Scaled Process Data Min = 0, Scaled Process Data Max = 1 Given those parameters, a raw value of 20 will be converted to .2 You can define how many digits to display under the "Display" tab. If you need to do more than scale, like add an offset or something, you'll need to continue to use the calculation mode. edit to add: After you scale, check that the input deadband on the I/O tab still makes sense. It auto-calculates based on scaling by default, but if you've modified it then it may need to be adjusted.
edited Jun 27 at 1:56 pm

That’s a really good idea. I didn’t even think about doing it that way. I’m on vacation, but can’t wait to try that out when I get back.

That’s a really good idea. I didn’t even think about doing it that way. I’m on vacation, but can’t wait to try that out when I get back.

Electronics/Electrical Technician
Hilliard Fletcher Wastewater Treatment Plant

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