Click save settings to reload page with unique web page address for bookmarking and sharing the current tool settings

Invert the low & high range limits for the measurement output settings

Flip tool with current settings to swap sqrt 4-20mA input (I) with measurement output parameters

**Square root extraction measurement products**

- Pitot tube air flow calculation 1000 hPa differential pressure transmitter
- 250″wc Orifice plate flow measurement dp transmitter
- DP transmitter with for measuring 300inH2O gas flow across orifice plate
- XMD Process Plant DP Cell Differential Pressure Transmitter

## Related Tools

- Linear measurement input to SqRt extractor 4-20mA output converter
- 4-20mA input to measurement output converter
- Measurement input to 4-20mA converter

## User Guide

This square root extraction current to linear measurement converter will take your entered electrical signal with a square root characteristic over the range of 4 to 20 milliamps and calculate the corresponding linear measurement. After values have been entered a conversion scale will be shown which corresponds to your entered measurement range parameters.

### Formula

This tool uses the following formula to calculate the the measurement reading output from a current signal input over a square root extraction 4-20mA range:

Measurement Rdg = Low Limit + (High Limit – Low Limit) x ((mA out -4) / 16)²

### Parameters

#### Square Root Extraction Signal (4-20mA) Reading

Add the sqrt 4-20mA current loop signal reading that you wish to convert.

#### Measurement Unit

Enter the measurement unit associated with the output values.

#### Lowest Linear Measurement

Add the minimum possible value for the linear measurement range of the square root extractor device. For example zero would be a typical value for most instrumentation. A value in any engineering units can be used as long as it relates to a linear measurement, and the same unit is used for the *Highest* value.

#### Highest Linear Measurement

Add the maximum possible value for the linear measurement range of the sqrt extractor instrument, e.g. full scale or full range value. Any measuring units can be used as long as it relates to a linear measurement, and the same unit is used as for the *Lowest* value.

#### Linear Measurement Reading – Answer

This is the ideal converted linear measurement for your square root extraction instrument, which represents the expected reading from a perfect instrument without any errors. The answer value is displayed in the same engineering unit that you entered for the *Lowest* and *Highest* range points.

**Square root extraction measurement products**

- ISOCON Universal Analogue Measurement and Control Signal Input to Output Converter
- Universal Strain Gauge Bridge Input Transmitter – STRAIN
- DP transmitter with for measuring 300inH2O gas flow across orifice plate
- DPS300 User Switchable Pressure Range, Volts or Current Output Low DP Sensor

## Help

### Conversion precision

*How precise is the conversion into measurement units?*

The linear measurement *Answer* is calculated to a precision of 9 significant figures.

### Convert sqrt 4-20mA to linear 4-20mA

*Can I use this calculator to convert sq rt extraction 4-20mA to a normal 4-20mA signal?*

Yes, just specify 4 for the *Lowest* limit and 20 for the *Highest* limit.

### Linear to sqrt characteristic

*How does the linear measurement change with respect to the sqrt current loop signal?*

As the sqrt signal increases, the linear reading will be slower to increase in comparison to the sqrt signal and will gradually increase and eventually overtake the linear scale when comparing each with the percentage of full scale.

### Switching input & output

*Does it matter if the square root extraction signal is the input or the output?*

No, it does not matter if the sqrt 4-20mA reading is an input or an output, the conversion will be the same to a linear measurement.

### Quickly identifying sqrt or linear 4-20mA

*Is there a quick way of determining whether a 4-20mA has a square root characteristic or a linear one?*

A 12mA sq rt current loop signal which is 50% of the 4-20mA scale will correspond to 25% of a linear measurement range.

**Square root extraction measurement products**

- 10 kPa orifice plate differential pressure transmitter for water flow measurement
- DPT200 Pressurised Tank Level Differential Pressure Transmitter
- ISOCON Universal Analogue Measurement and Control Signal Input to Output Converter
- XMD Process Plant DP Cell Differential Pressure Transmitter