In a hydraulic system, it’s beneficial to display the force being exerted by a hydraulic ram. Automation Products Group, Inc. (APG) offers digital pressure gauges that can display the pressure readings in a few industry-standard units, alongside other units for force, by using a simple conversion factor or multiplier.
PG7 and Custom Unit Converter
Years ago, a motorcycle design and manufacturing company used an APG 5000 PG7 Digital Pressure Gauge to measure pounds of force from a hydraulic ram. Pounds of force, however, isn’t a standard pressure unit displayed by the PG7. This calls for the custom unit converter function, which is built into all our gauges, and allows the sensor to read in pounds.
How to Convert PSI to LBS Using an APG Digital Pressure Gauge
Since the company wanted to measure pounds of force from the hydraulic ram, a few math equations are required. To convert PSI to LBS, multiply the pressure by the area over which the force is applied. The hydraulic ram’s manufacturer can provide the area, or it can be calculated on its own.
How to Calculate the Area of the Hydraulic Ram
To get the PSI to LBS multiplier, the first step is to determine the piston area of the 5-inch diameter hydraulic ram. The force is calculated by determining the area of the bore/piston side, as this is where the hydraulic fluid pressure is concentrated by the hydraulic pump. The formula for this is: Area = pi multiplied by the radius squared. So, multiply π (3.14) by 6.25 inches (radius of 2.5 inches squared) to get 19.625 square inches.
How To Calculate The Force Applied By The Hydraulic Ram
To set the gauge to display in LBS, use the area (19.625) in square inches calculated in the previous steps as the multiplier, and skip to the programming steps below.
The next step is to determine the total pounds of force (LBF). This is done by converting the full-scale PSI (pounds of force per square inch) to full-scale pounds. Multiply the maximum PSI from the PG7 by the hydraulic ram’s area in square inches. 19.625 square inches at 5000 PSI (19.625 X 5000) equals 98,125 LBF. This is a hard number to show on digital pressure gauge’s a four-digit display. The reading needs to be scaled to a larger unit of measure, such as tons.
Convert LBS to Tons
To determine the scale factor for tons, we convert the full-scale psi (pounds of force per square inch) to full-scale pounds. 19.625 square inches at 5000 psi (19.625 X 5000) equals 98,125 lbs. To convert this to tons, we will divide 98,125by 2000 lbs, or one ton, to get 49 tons. So, when our hydraulic ram is pressing down to full-scale measurement on our 5000 psi gauge, we want it to display 49 tons.
How To Calculate The Multiplier For Tons
Next, convert the total pounds of force calculated in the previous step to tons. Divide the pounds of force by one ton, or 2000 lbs. 98,125 LBF divided by 2000 LBS equals 49 tons. When the hydraulic ram is pressing down to full-scale measurement on the 5000 PSI gauge, the gauge displays 49 tons.
Programming Steps for Setting the APG Digital Pressure Gauge
Once the correct multiplier for the gauge and application is determined, set up the gauge to display the desired units.
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- Step 1: Press the On/Off button once to enter the main setup menu.
- Step 2: Press the Zero button to cycle through the options until UNITS is displayed.
- Step 3: Press the Select button to access the Units setting options.
- Step 4: Press Zero to cycle through the Units options until CUSTOM is displayed.
- Step 5: Press Select to access the Custom Units setting. A 5-digit conversion factor will appear with the first digit flashing.
- Step 6: Press the Zero button to change the value of the flashing digit (options: 0-9).
- Step 7: Press the Select button to accept the flashing digit and advance to the next digit. Repeat steps 6 and 7 as necessary.
- Step 8 After the last digit is accepted by pressing Select, use the Zero button to scroll through the custom units of measure; LBF, KN, LBS, KG, and NEWTON.
- Step 9: Press Select to accept the desired custom unit and return to the main setup menu.
- Step 10: Press Zero to scroll until you see EXIT, and press Select to return to the main display.
As always, let our Measurement Experts know if you have any questions about how to calculate your custom multiplier. Once you know your multiplier, APG’s digital pressure gauges make converting PSI to LBS easy!
WRITTEN BY
Sami T.
Sami Thompson is APG’s Marketing Technical Writer and has been with the company since 2022. With a master’s degree in English from Utah State University and a 40-page thesis publication under her belt, Sami has a demonstrated strong writing background. In her free time, Sami enjoys reading and birdwatching.