# Instrument calibration tables

## Instrumentation and Process Control

• #### Question 1

A digital pressure transmitter has a calibrated input range of 0 to 75 PSI, and a 14-bit output (0 to 16383 count’’ range). Complete the following table of values for this transmitter, assuming perfect calibration (no error):

$$\begin{array} {|l|l|} \hline Input pressure & Percent of span & Counts & Counts \\ \hline (PSI) & ( \\ \hline \ & 0 & & \\ \hline & 36 & & \\ \hline & 62 & & \\ \hline & 89 & & \\ \hline & 95 & & \\ \hline \end{array}$$

• #### Question 2

Suppose you wish to calibrate a thermocouple temperature transmitter to an input range of 0 to 1500 degrees F, with an output range of 4 to 20 mA. Complete the following calibration table showing the proper test temperatures and the ideal output signals at those levels:

$$\begin{array} {|l|l|} \hline Input temp & Percent of span & Output signal \\ \hline applied (deg F) & ( \\ \hline \ & 0 & \\ \hline & 25 & \\ \hline & 50 & \\ \hline & 75 & \\ \hline & 100 & \\ \hline \end{array}$$

• #### Question 3

A temperature transmitter has a calibrated range of -80 to 150 degrees F and its output signal range is 4 to 20 mA. Complete the following table of values for this transmitter, assuming perfect calibration (no error). Be sure to show your work!

$$\begin{array} {|l|l|} \hline Measured temp & Percent of span & Output signal \\ \hline (^{o}F) & ( \\ \hline \120 & & \\ \hline -45 & & \\ \hline & 42 & \\ \hline & 25 & \\ \hline & & 7.5 \\ \hline & & 12.9 \\ \hline \end{array}$$

• #### Question 4

A Foxboro pneumatic square root extractor has a calibrated range of 3 to 15 PSI for both input and output. Complete the following table of values for this relay, assuming perfect calibration (no error). Be sure to show your work!

$$\begin{array} {|l|l|} \hline Input signal & Percent of input & Percent of output & Output signal \\ \hline (PSI) & span ( \\ \hline \5 & & & \\ \hline 13 & & & \\ \hline & 50 & & \\ \hline & 30 & & \\ \hline & & 80 & \\ \hline & & 15 & \\ \hline & & & 7 \\ \hline & & & 12 \\ \hline \end{array}$$

• #### Question 5

Every instrument has at least one input and at least one output. For instruments responding linearly, the correspondence between input and output is proportional:

A practical example of this is a pressure transmitter, in this case one with an input range of 0 to 1023 PSI and an output of 4-20 mA:

If you happened to measure an output current of 14.7 mA from this pressure transmitter, it would be a simple matter for you to calculate the corresponding input pressure to be 684.13 PSI.

However, students are often taken by surprise when they encounter an analog-to-digital converter (ADC) or digital-to-analog converter (DAC) and are asked to correlate input and output for such devices. What might seem a daunting task at first, though, soon reveals itself to be the same input-to-output correspondence calculations they’ve seen all along in the guise of analog sensors and other instruments.

Take for example this analog-to-digital converter, with a 10-bit output (a count’’ range of 0 to 1023) and a 4-20 mA input:

Calculate the corresponding count’’ output of this ADC circuit given a 6.82 mA input signal.

• #### Question 6

The ADC0804 is an example of an integrated circuit analog-to-digital converter (ADC), converting an analog input voltage signal into an 8-bit binary output:

When operated from a 5.0 volt DC power supply in its simplest mode, the ADC0804 converts any DC input voltage between 0.0 volts and 5.0 volts into an 8-bit number at the command of a clock pulse. A 0.0 volt input yields a binary output (or count’‘) of {\tt 00000000}, of course, while a 5.0 volt input yields a count of {\tt 11111111}.

Complete this table of numbers, relating various DC input voltages with count values (expressed in binary, hex, and decimal) for an ADC0804 having an input range of 0.0 to 5.0 volts DC:

$$\begin{array} {|l|l|} \hline DC input voltage & Binary count & Hex count & Decimal count \\ \hline 0.0 volts & 00000000 & & \\ \hline & 00110011 & & 51 \\ \hline 2.2 volts & & 70 & \\ \hline & & B3 & 179 \\ \hline & 11001100 & CC & \\ \hline 5.0 volts & 11111111 & & \\ \hline \end{array}$$

• #### Question 7

An analog-to-digital converter has a 12-bit binary output and an analog input voltage range of 0.0 to + 5.0 volts. Calculate:

{\bullet} The analog input corresponding to a digital output of {\tt 2D0} =

{\bullet} The analog input corresponding to a digital output of {\tt F14} =

• #### Question 8

An analog-to-digital converter has a 16-bit binary output and an analog input voltage range of 0.0 to + 10.0 volts. Calculate:

{\bullet} The analog input corresponding to a digital output of {\tt 3D6A} =

{\bullet} The analog input corresponding to a digital output of {\tt C005} =

• #### Question 9

An analog-to-digital converter (ADC) has a calibrated input range of 0 to 10 volts, and a 12-bit output (0 to 4095 count’’ range). Complete the following table of values for this converter, assuming perfect calibration (no error):

$$\begin{array} {|l|l|} \hline Input voltage & Percent of span & Counts & Counts \\ \hline (volts) & ( \\ \hline \ & 0 & & \\ \hline & 25 & & \\ \hline & 50 & & \\ \hline & 75 & & \\ \hline & 100 & & \\ \hline \end{array}$$

• #### Question 10

An essential component of any digital control system is an {\it analog-to-digital converter}, or {\it ADC}. This is necessary to convert the analog process variable measurement into a digital number for the control algorithm to process. Another essential component is a {\it digital-to-analog converter}, or {\it DAC}, which does the exact opposite.

In a system using 4-20 mA analog currents to relay instrument signals, there is an ADC located at the process variable input of the controller, and a DAC located at the output of the controller:

In digital Fieldbus’’ systems, the communication is all digital, which places the ADC at the transmitter and the DAC at the transducer:

In either case, we need to scale’’ the binary count of the ADC and DAC to their respective analog variable values. Consider a flow control system, with a flow transmitter ranged from 0 to 200 GPM and a pneumatic control valve operating on a pressure range of 3 to 15 PSI (instrument air). Assuming the ADC has a resolution of 16 bits (a digital conversion range of \$0000 to \$FFFF) and the DAC has a resolution of 14 bits (a digital conversion range of \$0000 to \$3FFF), determine the digital values corresponding to a 50

{\bf Calibration table for process variable signal (ADC)}

$$\begin{array} {|l|l|} \hline Measurement & Digital output \\ \hline 0 GPM & \0000 \\ \hline 100 GPM & \\ \hline 200 GPM & \FFFF \\ \hline \end{array}$$

• #### Question 11

An analog-to-digital converter (ADC) has a calibrated input range of 0 to 10 volts, and a 16-bit output (0 to 65535 count’’ range). Complete the following table of values for this converter, assuming perfect calibration (no error):

$$\begin{array} {|l|l|} \hline Input voltage & Percent of span & Counts & Counts \\ \hline (volts) & ( \\ \hline \ & 0 & & \\ \hline & 25 & & \\ \hline & 50 & & \\ \hline & 75 & & \\ \hline & 100 & & \\ \hline \end{array}$$

• #### Question 12

Suppose you wish to calibrate an RTD temperature transmitter to an input range of 50 to 200 degrees F, with an output range of 4 to 20 mA. Complete the following calibration table showing the proper test temperatures and the ideal output signals at those levels:

$$\begin{array} {|l|l|} \hline Input temp & Percent of span & Output signal \\ \hline applied (deg F) & ( \\ \hline \ & 0 & \\ \hline & 25 & \\ \hline & 50 & \\ \hline & 75 & \\ \hline & 100 & \\ \hline \end{array}$$

• #### Question 13

A digital pressure transmitter has a calibrated input range of 50 to 200 PSI, and a 10-bit output (0 to 1023 count’’ range). Complete the following table of values for this transmitter, assuming perfect calibration (no error):

$$\begin{array} {|l|l|} \hline Input pressure & Percent of span & Counts & Counts \\ \hline (PSI) & ( \\ \hline \ & 7 & & \\ \hline & 22 & & \\ \hline & 39 & & \\ \hline & 56 & & \\ \hline & 78 & & \\ \hline \end{array}$$

• #### Question 14

A digital level transmitter has a calibrated input range of 20 to 170 inches of liquid level, and a 10-bit output (0 to 1023 count’’ range). Complete the following table of values for this transmitter, assuming perfect calibration (no error):

$$\begin{array} {|l|l|} \hline Input level & Percent of span & Counts & Counts \\ \hline (inches) & ( \\ \hline \ & 11 & & \\ \hline & 28 & & \\ \hline & 55 & & \\ \hline & 73 & & \\ \hline & 92 & & \\ \hline \end{array}$$

• #### Question 15

An analog-to-digital converter (ADC) has a calibrated input range of 0 to 5 volts, and a 12-bit output. Complete the following table of values for this converter, assuming perfect calibration (no error):

$$\begin{array} {|l|l|} \hline Input voltage & Percent of span & Counts & Counts \\ \hline (volts) & ( \\ \hline \1.6 & & & \\ \hline & & 3022 & \\ \hline & 40 & & \\ \hline & & & A2F \\ \hline \end{array}$$

• #### Question 16

Suppose a FOUNDATION Fieldbus pressure transmitter is connected to measure the pressure of natural gas inside a pipeline. The expected range of pressure inside this vessel is 0 to 600 PSI.

Determine the proper configuration parameters for this Fieldbus instrument’s Analog Input (AI) block:

$$\begin{array} {|l|l|} \hline {\tt L\_Type} & 50pt \\ \hline {\tt XD\_Scale} & 50pt \\ \hline {\tt OUT\_Scale} & 50pt \\ \hline \end{array}$$

• #### Question 17

Suppose a FOUNDATION Fieldbus differential pressure transmitter is connected to measure the pressure drop created by an orifice plate, proportional to the square of fluid flow rate through the orifice. At a flow rate of 400 GPM, the orifice produces a pressure differential of 135 inches water column.

Determine the proper configuration parameters for this Fieldbus instrument’s Analog Input (AI) block:

$$\begin{array} {|l|l|} \hline {\tt L\_Type} & 50pt \\ \hline {\tt XD\_Scale} & 50pt \\ \hline {\tt OUT\_Scale} & 50pt \\ \hline \end{array}$$

• #### Question 18

Suppose a FOUNDATION Fieldbus pressure transmitter is connected to the hydraulic line supplying fluid pressure to a ram, for the purpose of measuring the ram’s exerted force based on sensed pressure. Recall that the relationship between force and fluid pressure for a piston is $F = PA$, where $F$ is force in pounds, $A$ is surface area of the piston in square inches, and $P$ is fluid pressure in PSI. Recall as well that the area for a circular object is given by the formula $A = \pi r^2$.

Supposing the ram’s piston has a diameter of exactly 2 inches, determine the proper configuration parameters for this Fieldbus instrument’s Analog Input (AI) block, assuming we wish this transmitter to report ram force over a range of 0 to 4700 pounds.

$$\begin{array} {|l|l|} \hline {\tt L\_Type} & 50pt \\ \hline {\tt XD\_Scale} & 50pt \\ \hline {\tt OUT\_Scale} & 50pt \\ \hline \end{array}$$

• #### Question 19

Suppose a FOUNDATION Fieldbus pressure transmitter is connected to the bottom of a vessel containing a liquid half as dense as water, for the purpose of measuring liquid height inside the vessel based on hydrostatic pressure. For every foot of liquid height, 6 inches water column pressure is sensed by the transmitter.

Determine the proper configuration parameters for this Fieldbus instrument’s Analog Input (AI) block, assuming we wish this transmitter to report liquid height over a range of 0 to 18 feet:

$$\begin{array} {|l|l|} \hline {\tt L\_Type} & 50pt \\ \hline {\tt XD\_Scale} & 50pt \\ \hline {\tt OUT\_Scale} & 50pt \\ \hline \end{array}$$

• #### Question 20

Suppose a FOUNDATION Fieldbus pressure transmitter is connected to the bottom of a water storage tank, for the purpose of measuring water volume stored inside the tank based on hydrostatic pressure. The tank is shaped like a vertical cylinder, 10 feet in diameter and 20 feet high.

Determine the proper configuration parameters for this Fieldbus instrument’s Analog Input (AI) block, assuming we wish this transmitter to report liquid height over a range of 0 to 15 feet, expressed in units of cubic feet:

$$\begin{array} {|l|l|} \hline {\tt L\_Type} & 50pt \\ \hline {\tt XD\_Scale} & 50pt \\ \hline {\tt OUT\_Scale} & 50pt \\ \hline \end{array}$$

• #### Question 21

Suppose a FOUNDATION Fieldbus pressure transmitter is connected to the bottom of a liquid storage vessel for the purpose of measuring liquid height based on hydrostatic pressure. This transmitter happens to be configured with the following Analog Input (AI) block parameters:

$$\begin{array} {|l|l|} \hline {\tt L\_Type} & Indirect \\ \hline {\tt XD\_Scale} & 38 to 183.488 inches WC \\ \hline {\tt OUT\_Scale} & 0 to 14 feet \\ \hline \end{array}$$

• #### Question 22

Suppose you wish to calibrate a pneumatic pressure transmitter to an input range of -10 to +50 inches of mercury, with an output range of 3 to 15 PSI. Complete the following calibration table showing the test pressures to use and the allowable low/high output signals for a calibrated tolerance of +/- 0.5

$$\begin{array} {|l|l|} \hline Input pressure & Percent of span & Output signal & Output signal & Output signal \\ \hline applied (” Hg) & ( \\ \hline \ & 0 & & & \\ \hline & 25 & & & \\ \hline & 50 & & & \\ \hline & 75 & & & \\ \hline & 100 & & & \\ \hline \end{array}$$

• #### Question 23

A tachogenerator is used to measure the rotary speed of a machine. Its calibrated range is 0 to 1500 RPM (revolutions per minute) and its corresponding signal output is 0 to 10 volts DC. Given these range values, calculate the output voltages for the following input shaft speeds, and then describe how you were able to correlate the different speeds to output voltage values:

$$\begin{array} {|l|l|} \hline Shaft speed & Output voltage \\ \hline (RPM) & (volts DC) \\ \hline 100 & \\ \hline 350 & \\ \hline 500 & \\ \hline 750 & \\ \hline 890 & \\ \hline 975 & \\ \hline 1230 & \\ \hline 1410 & \\ \hline 1500 & \\ \hline \\ \hline \end{array}$$

• #### Question 24

Suppose you wish to calibrate an electronic pressure transmitter to an input range of 0 to 50 PSI, with an output range of 4 to 20 mA. Complete the following calibration table showing the proper test pressures and the ideal output signal levels at those pressures:

$$\begin{array} {|l|l|} \hline Input pressure & Percent of span & Output signal \\ \hline applied (PSI) & ( \\ \hline \ & 0 & \\ \hline & 25 & \\ \hline & 50 & \\ \hline & 75 & \\ \hline & 100 & \\ \hline \end{array}$$

• #### Question 25

Suppose you wish to calibrate an electronic pressure transmitter to an input range of 0 to 200 PSI, with an output range of 4 to 20 mA. Complete the following calibration table showing the proper test pressures and the ideal output signal levels at those pressures:

$$\begin{array} {|l|l|} \hline Input pressure & Percent of span & Output signal \\ \hline applied (PSI) & ( \\ \hline \ & 0 & \\ \hline & 25 & \\ \hline & 50 & \\ \hline & 75 & \\ \hline & 100 & \\ \hline \end{array}$$

• #### Question 26

In instrumentation parlance, a {\it transducer} is a calibrated device used to convert one standardized signal into another standardized signal. One very common form of transducer is an {\it I/P transducer}, which converts an electric current signal into a pneumatic pressure signal:

The symbols shown above are standard for process and instrumentation diagrams (P\&ID’s), where an electric cable is shown as a dashed line, a pneumatic pipe or tube shown as a line with double hash-marks periodically drawn through it, and the instrument is a circle with letters (in this case, Y’‘, representing a signal relay, computing element, transducer, or converter).

The most popular range for electric current signals is 4 to 20 mA DC. The most common range for pneumatic (air pressure) signals is 3 to 15 PSI. Therefore, the most common type of I/P transducer has an input range of 4-20 mA and an output range of 3-15 PSI. Both of these ranges are there to represent some measured or manipulated quantity in an instrument system. That is, 0

Complete all the missing data in the following calibration table for this I/P transducer, and then describe how you were able to correlate the different percentages of range with specific current and pressure signal values:

$$\begin{array} {|l|l|} \hline Input current & Percent of range & Output pressure \\ \hline (mA) & ( \\ \hline \4 & 0 & 3 \\ \hline & 10 & \\ \hline & 20 & \\ \hline & 25 & \\ \hline & 30 & \\ \hline & 40 & \\ \hline 12 & 50 & 9 \\ \hline & 60 & \\ \hline & 70 & \\ \hline & 75 & \\ \hline & 80 & \\ \hline & 90 & \\ \hline 20 & 100 & 15 \\ \hline \end{array}$$

• #### Question 27

Suppose you wish to calibrate a current-to-pressure (I/P’‘) transducer to an output range of 3 to 15 PSI, with an input range of 4 to 20 mA. Complete the following calibration table showing the proper test pressures and the ideal input signal levels at those pressures:

$$\begin{array} {|l|l|} \hline Input signal & Percent of span & Output pressure \\ \hline applied (mA) & ( \\ \hline \ & 35 & \\ \hline & 80 & \\ \hline & 95 & \\ \hline \end{array}$$

• #### Question 28

An electronic level transmitter has a calibrated range of 0 to 2 feet, and its output signal range is 4 to 20 mA. Complete the following table of values for this transmitter, assuming perfect calibration (no error). Be sure to show your work!

$$\begin{array} {|l|l|} \hline Measured level & Percent of span & Output signal \\ \hline (feet) & ( \\ \hline \1.6 & & \\ \hline & & 7.1 \\ \hline & 40 & \\ \hline \end{array}$$

• #### Question 29

A pneumatic level transmitter has a calibrated range of 0 to 5 feet, and its output signal range is 3 to 15 PSI. Complete the following table of values for this transmitter, assuming perfect calibration (no error). Be sure to show your work!

$$\begin{array} {|l|l|} \hline Measured level & Percent of span & Output signal \\ \hline (feet) & ( \\ \hline \3.2 & & \\ \hline & & 4 \\ \hline & 50 & \\ \hline 2.4 & & \\ \hline & & 11.3 \\ \hline & 18 & \\ \hline \end{array}$$

• #### Question 30

Suppose you wish to calibrate an electronic pressure transmitter to an input range of 0 to 50 inches of water, with an output range of 4 to 20 mA. Complete the following calibration table showing the proper test pressures and the ideal output signal levels at those pressures:

$$\begin{array} {|l|l|} \hline Input pressure & Percent of span & Output signal \\ \hline applied (” W.C.) & ( \\ \hline \ & 5 & \\ \hline & 33 & \\ \hline & 61 & \\ \hline \end{array}$$

• #### Question 31

An electronic pressure transmitter has a calibrated range of 0 to 200 inches of mercury, and its output signal range is 4 to 20 mA. Complete the following table of values for this transmitter, assuming perfect calibration (no error):

$$\begin{array} {|l|l|} \hline Input pressure & Percent of span & Output signal \\ \hline applied (” Hg) & ( \\ \hline \24 & & \\ \hline & 19 & \\ \hline & & 11.7 \\ \hline \end{array}$$

• #### Question 32

Suppose you had a current-to-pressure (I/P’‘) transducer with an output range of 3 to 15 PSI and an input range of 4 to 20 mA. The following calibration table shows several input signal levels and their corresponding percentages of span and output pressures:

$$\begin{array} {|l|l|} \hline Input signal & Percent of span & Output pressure \\ \hline applied (mA) & ( \\ \hline \6.88 & 18 & 5.16 \\ \hline 5.1 & 6.88 & 3.83 \\ \hline 12.8 & 55 & 9.6 \\ \hline 17.44 & 84 & 13.08 \\ \hline 6.53 & 15.83 & 4.9 \\ \hline \end{array}$$

• #### Question 33

A pneumatic differential pressure transmitter has a calibrated range of $-100$ to +100 inches of water column (” W.C.), and its output signal range is 3 to 15 PSI. Complete the following table of values for this transmitter, assuming perfect calibration (no error). Be sure to show your work!

$$\begin{array} {|l|l|} \hline Input pressure & Percent of span & Output signal \\ \hline applied (“W.C.) & ( \\ \hline \0 & & \\ \hline -30 & & \\ \hline & & 8 \\ \hline & & 13 \\ \hline & 65 & \\ \hline & 10 & \\ \hline \end{array}$$

• #### Question 34

A turbine flowmeter measuring cooling water for a large power generator uses an electronic circuit to convert its pickup coil pulses into a 4-20 mA analog current signal. The K factor’’ for the turbine element is 99 pulses per gallon, and the 4-20 mA analog output is ranged from 0 to 500 GPM flow. Complete the following table of values for this transmitter, assuming perfect calibration (no error). Be sure to show your work!

$$\begin{array} {|l|l|} \hline Measured flow & Pickup signal & Percent of output & Output signal \\ \hline (GPM) & frequency (Hz) & span ( \\ \hline \250 & & & \\ \hline 412 & & & \\ \hline & 305 & & \\ \hline & 780 & & \\ \hline & & 63 & \\ \hline & & 49 & \\ \hline & & & 10 \\ \hline & & & 16 \\ \hline \end{array}$$

• #### Question 35

Suppose you wish to calibrate a turbine flowmeter to an input range of 0 to 600 gallons per minute. The $k$ factor for this turbine is 20 pulses per gallon, making the input frequency range 0 to 200 Hz for this flow range. The output signal range is 4 to 20 mA. Complete the following calibration table showing the proper test frequencies and the ideal output signals at those levels:

$$\begin{array} {|l|l|} \hline Simulated flow & Input frequency & Percent of span & Output signal \\ \hline rate (GPM) & applied (Hz) & ( \\ \hline \97 & & & \\ \hline & & 25 & \\ \hline & & 60 & \\ \hline 400 & & & \\ \hline \end{array}$$

• #### Question 36

Suppose you wish to calibrate a turbine flowmeter to an input range of 0 to 300 gallons per minute. The $k$ factor for this turbine is 80 pulses per gallon, making the input frequency range 0 to 400 Hz for this flow range. The output signal range is 4 to 20 mA. Complete the following calibration table showing the proper test frequencies and the ideal output signals at those levels:

$$\begin{array} {|l|l|} \hline Simulated flow & Input frequency & Percent of span & Output signal \\ \hline rate (GPM) & applied (Hz) & ( \\ \hline \ & & 17 & \\ \hline 130 & & & \\ \hline & & 45 & \\ \hline 300 & & & \\ \hline \end{array}$$

• #### Question 37

Suppose you wish to calibrate a turbine flowmeter to an input range of 0 to 800 gallons per minute. The $k$ factor for this turbine is 30 pulses per gallon, making the input frequency range 0 to 400 Hz for this flow range. The output signal range is 4 to 20 mA. Complete the following calibration table showing the proper test frequencies and the ideal output signals at those levels:

$$\begin{array} {|l|l|} \hline Simulated flow & Input frequency & Percent of span & Output signal \\ \hline rate (GPM) & applied (Hz) & ( \\ \hline \55 & & & \\ \hline & & 25 & \\ \hline & & 63 & \\ \hline 700 & & & \\ \hline \end{array}$$

• #### Question 38

An electronic pressure transmitter has a calibrated range of -10 to 60 PSI, and its output signal range is 4 to 20 mA. Complete the following table of values for this transmitter, assuming perfect calibration (no error). Be sure to show your work!

$$\begin{array} {|l|l|} \hline Input pressure & Percent of span & Output signal \\ \hline applied (PSI) & ( \\ \hline \0 & & \\ \hline -5 & & \\ \hline & & 12 \\ \hline & & 13.6 \\ \hline & 40 & \\ \hline & 22 & \\ \hline \end{array}$$

• #### Question 39

A pneumatic level transmitter has a calibrated range of 150 inches to 300 inches of liquid level, with an output range of 3 to 15 PSI. Complete the following table of values for this transmitter, assuming perfect calibration (no error):

$$\begin{array} {|l|l|} \hline Input level & Percent of span & Output signal \\ \hline applied (inches) & ( \\ \hline \ & 4 & \\ \hline & & 7.2 \\ \hline 189 & & \\ \hline \end{array}$$

• #### Question 40

Suppose you wish to calibrate a pneumatic level transmitter to an input range of 0 to 400 inches, with an output range of 3 to 15 PSI. Complete the following calibration table showing the proper test levels and the ideal output signals at those levels:

$$\begin{array} {|l|l|} \hline Input level & Percent of span & Output signal \\ \hline applied (inches) & ( \\ \hline \ & 0 & \\ \hline & 25 & \\ \hline & 50 & \\ \hline & 75 & \\ \hline & 100 & \\ \hline \end{array}$$

• #### Question 41

An ultrasonic level transmitter has a calibrated range of 40 to 75 inches and its output signal range is 4 to 20 mA. Complete the following table of values for this transmitter, assuming perfect calibration (no error). Be sure to show your work!

$$\begin{array} {|l|l|} \hline Measured level & Percent of span & Output signal \\ \hline (inches) & ( \\ \hline \47 & & \\ \hline & & 6 \\ \hline & 75 & \\ \hline 60 & & \\ \hline & & 15.1 \\ \hline & 34 & \\ \hline \end{array}$$