Inst ToolsInst ToolsInst Tools
  • Courses
  • Videos
  • Q & A
    • Interview
      • Instrumentation
      • Electronics
      • Electrical
      • Practical Questions
    • MCQ
      • Instrumentation MCQ
      • Electrical MCQ
      • Electronics MCQ
      • Control Systems MCQ
      • Analog Electronics MCQ
      • Digital Electronics MCQ
      • Power Electronics MCQ
      • Microprocessor MCQ
      • Multiple Choice Questions
  • EE
    • Electronics
      • Electronics Q & A
      • Electronic Basics
      • Electronic Devices & Circuits
      • Electronics Animation
      • Digital Electronics
    • Electrical
      • Electrical Basics
      • Electrical Q & A
      • Power Electronics
      • Electrical Machines
      • Electrical Animation
      • Power Systems
      • Switchgear & Protection
      • Transmission & Distribution
  • Measure
    • Control Valves
    • Calibration
    • Temperature
    • Pressure
    • Flow
    • Level
    • Analyzers
    • Switches
    • Vibration
    • Solenoid Valve
  • Control
    • PLC Tutorials
    • Control Systems
    • Safety Instrumented System (SIS)
    • Communication
    • Fire & Gas System
  • More
    • Design
    • Tools
    • Animation
    • Basics
    • Formulas
    • Standards
    • TextBooks
    • Common
    • Software
    • Excel Tools
    • Erection & Commissioning
    • Process Fundamentals
    • Videos
    • Books
Search
All rights reserved. Reproduction in whole or in part without written permission is prohibited.
Reading: How to Read Gauge Analog Scales
Share
Notification Show More
Font ResizerAa
Inst ToolsInst Tools
Font ResizerAa
  • Courses
  • PLC Tutorials
  • Control Systems
Search
  • Courses
  • Videos
  • Q & A
    • Interview
    • MCQ
  • EE
    • Electronics
    • Electrical
  • Measure
    • Control Valves
    • Calibration
    • Temperature
    • Pressure
    • Flow
    • Level
    • Analyzers
    • Switches
    • Vibration
    • Solenoid Valve
  • Control
    • PLC Tutorials
    • Control Systems
    • Safety Instrumented System (SIS)
    • Communication
    • Fire & Gas System
  • More
    • Design
    • Tools
    • Animation
    • Basics
    • Formulas
    • Standards
    • TextBooks
    • Common
    • Software
    • Excel Tools
    • Erection & Commissioning
    • Process Fundamentals
    • Videos
    • Books
Follow US
All rights reserved. Reproduction in whole or in part without written permission is prohibited.
Inst Tools > Blog > Pressure Measurement > How to Read Gauge Analog Scales

How to Read Gauge Analog Scales

Last updated: January 18, 2019 8:17 am
Editorial Staff
Pressure Measurement
2 Comments
Share
5 Min Read
SHARE

1. Interpret the pressure measurement displayed by this gauge mechanism, assuming a gauge accuracy of ± 1% full scale:

Pressure Gauge Analog Scale

Contents
1. Interpret the pressure measurement displayed by this gauge mechanism, assuming a gauge accuracy of ± 1% full scale:How low and how high could this pressure actually be, given the stated accuracy of this gauge?Answer2. Interpret the pressure measurement displayed by this gauge mechanism, assuming a gauge accuracy of ± 2% full scale:How low and how high could this pressure actually be, given the stated accuracy of this gauge?Answer3. Interpret the pressure measurement displayed by this gauge mechanism, assuming a gauge accuracy of ± 0.5% full scale:How low and how high could this pressure actually be, given the stated accuracy of this gauge?Answer4. Interpret the pressure measurement displayed by this gauge mechanism, assuming a gauge accuracy of ± 2% full scale: How low and how high could this pressure actually be, given the stated accuracy of this gauge?Answer :5. Interpret the pressure measurement displayed by this gauge mechanism, assuming a gauge accuracy of ± 2% full scale:How low and how high could this pressure actually be, given the stated accuracy of this gauge?Answer :6. Interpret the temperature measurement displayed by this gauge mechanism, and also identify the meaning of the other pointer:Answer :7. Interpret the measurement displayed by this Level Indicator :Answer :8. Interpret the air flow measurement displayed by this rotameter:Answer :9. Interpret the pressure measurement displayed by this U-tube manometer, recalling that the pressure will be equal to the difference in heights between the two liquid columns:Answer :

How low and how high could this pressure actually be, given the stated accuracy of this gauge?

Answer

Pressure = 3750 PSI ± 60 PSI

This means the actual pressure could be as low as 3690 PSI or as high as 3810 PSI

2. Interpret the pressure measurement displayed by this gauge mechanism, assuming a gauge accuracy of ± 2% full scale:

Pressure Gauge Scale

How low and how high could this pressure actually be, given the stated accuracy of this gauge?

Answer

Pressure = 7800 PSI ± 400 PSI

This means the actual pressure could be as low as 7400 PSI or as high as 8200 PSI

3. Interpret the pressure measurement displayed by this gauge mechanism, assuming a gauge accuracy of ± 0.5% full scale:

Pressure Gauge Measurement

How low and how high could this pressure actually be, given the stated accuracy of this gauge?

Answer

Pressure = 560 PSI ± 5 PSI

This means the actual pressure could be as low as 555 PSI or as high as 565 PSI.

4. Interpret the pressure measurement displayed by this gauge mechanism, assuming a gauge accuracy of ± 2% full scale: 

Pressure Gauge Reading

How low and how high could this pressure actually be, given the stated accuracy of this gauge?

Answer :

Pressure = 2.5 ”H2O ± 0.6 ”H2O. This means the actual pressure could be as low as 1.9 ”H2O or as high as 3.1 ”H2O.

If you look closely at the photograph, you can see that the camera’s angle to the gauge face is not straight-on, and therefore there will be some parallax error in reading this gauge’s face.

If we were to lower the camera’s view to get a more direct look at the gauge, we might see the needle pointing between the 2.5 and 3 divisions, which would mean a pressure of 2.75 ”H2O ±0.6 ”H2O.

5. Interpret the pressure measurement displayed by this gauge mechanism, assuming a gauge accuracy of ± 2% full scale:

Gauge Display Scale

How low and how high could this pressure actually be, given the stated accuracy of this gauge?

Answer :

Pressure = 14 PSI ± 2 PSI

This means the actual pressure could be as low as 12 PSI or as high as 16 PSI.

6. Interpret the temperature measurement displayed by this gauge mechanism, and also identify the meaning of the other pointer:

Temperature Gauge Reading

Answer :

The current temperature is 40 degrees Celsius (red pointer), and the other pointer is a low-temperature capture. In this case, the “capture” pointer shows that the temperature went down as low as 20 degrees Celsius (or perhaps a bit lower, since parallax error is making that pointer appear to read higher than it actually is).

7. Interpret the measurement displayed by this Level Indicator :

Level Indicator Display Scale

Answer :

The red pointer shows 61% process level. The setpoint is a few percent less than that.

8. Interpret the air flow measurement displayed by this rotameter:

Rotameter Scale Reading

Answer :

Rounding to the nearest half-division, we see the center of the ball-plummet nearest the “1” mark. No units of measurement are specified on the scale (from this viewing angle, anyway), and so we cannot say if this is 1 SCFH, 1 SCFM, or anything else.

9. Interpret the pressure measurement displayed by this U-tube manometer, recalling that the pressure will be equal to the difference in heights between the two liquid columns:

Level Gauge using Manometer

Answer :

The pressure difference is approximately 22 inches of liquid column.

Credits : by Tony R. Kuphaldt – under CC BY 1.0

Don't Miss Our Updates
Be the first to get exclusive content straight to your email.
We promise not to spam you. You can unsubscribe at any time.
Invalid email address
You've successfully subscribed !

Recommended Articles

Electronic Pressure Sensors Principle
Pressure Gauge Syphons Principle
Pressure Gauge Installation at Pump Discharge
DP Transmitter Block and Bleed Valves
Impulse Line Purging and Close Coupling of Instruments
The Principle of Dead Weight Pressure Tester
Share This Article
Facebook Whatsapp Whatsapp LinkedIn Copy Link
Share
2 Comments
  • Fred says:
    March 9, 2020 at 2:56 pm

    question 5 – is that right 700kpa = 101psi I think

    Reply
  • Scott says:
    November 18, 2022 at 11:28 pm

    That is the way I was taught to do in working at powerplants for many years.
    Now, I have worked in pharma and they insist what you’re saying is impossible.
    They insist you put the gauge needle exactly on the cal value, then record the number off of the test standard! They put like 50.248 PSI. Where I came from they would be like you can’t read that on a gauge. I was taught the gauge could increment could be read in half; unless the gauge had a mirrored back (standard gauge), then it could be read in 1/4 increments.

    Reply

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Stay Connected

128.3kFollowersLike
69.1kFollowersFollow
208kSubscribersSubscribe
38kFollowersFollow

Categories

Recent Comments

  • William Snyder on Top Non-PLC Certification Courses for Automation Professionals
  • Kamli on Top Free PLC Software
  • Guifty Shimica on Top Non-PLC Certification Courses for Automation Professionals
  • Guifty Shimica on Top Non-PLC Certification Courses for Automation Professionals

Related Articles

Pressure Gauge with Block and Bleed Valves

Pressure Gauge with Block and Bleed Valves

Differential Pressure Gauge Principle

Piston Type Differential Pressure Gauge Principle

Sensor Trim and Output Trim in Smart Transmitter

What is Sensor Trim and Output Trim in Smart Transmitter?

diaphragm-pressure-gauge

Diaphragm Pressure Sensors

Pressure Detection Circuit

Pressure Detection Circuit

Linear Variable Displacement Transducer (LVDT)

What is LVDT ?

Differential Pressure Switch Principle

Differential Pressure Switch Principle

PLC Raw Count Calculation formula for Pressure Transmitter

PLC Raw Count Calculation for Pressure Transmitter

More Articles

Wood Sawing and Blower System PLC Control Design

Wood Sawing and Blower System: PLC Control Design

Control Valves Chemical attack Problems

Control Valves Chemical attack Problems

Feedback Accelerometer System Objective Questions

Feedback Accelerometer System Objective Questions

Process vessel for measuring water level

Level Measurement Lab Exercise

RDOL starter

What are DOL and RDOL starters? Advantages, Disadvantages

Fail Safe Switch Circuit

Basics of Fail-safe Circuits

Diode-positive-limiter

Positive & Negative Diode Clippers

Use of Regions in SCL Language

Use of Regions in SCL Language

Follow US
All rights reserved. Reproduction in whole or in part without written permission is prohibited.
Welcome Back!

Sign in to your account

Username or Email Address
Password

Lost your password?