MNM Scales 20,000 lb S-Type Load Cell Crane Scale Guide: 1 lb Accuracy, LP7515 & Full Specs
- pete8781
- Jul 29
- 10 min read
Need more details, application help, or assistance choosing the right capacity? Call MNM Scales at (832) 290-3120 or email mnmscales@yahoo.com.
The MNM Scales 20,000 lb S-Type Load Cell Crane Scale is a calibrated 20,000 lb x 1 lb tension/compression weighing system built around a heavy-capacity alloy-steel S-type load cell and the MNM LP7515 digital weight indicator. It is designed for users who need to measure suspended, inline, pull-test, tension, or compression loads while keeping the display separate from the load point.
What makes the Crane-20k package especially useful is that it is sold as a complete weighing system rather than as a loose load cell. The package combines the 20,000 lb sensor, digital readout, power supply, battery capability, eye-bolt hardware and calibration so the system arrives configured for a 20,000 lb capacity with 1 lb display increments. For fabrication shops, test departments, rigging operations, agriculture, industrial maintenance and material-handling facilities, this can eliminate much of the component matching normally required when building a custom tension scale.
MNM Scales Crane-20k at a Glance
Model/SKU: Crane-20k
Maximum weighing capacity: 20,000 lb
Displayed increment: 1 lb
Load cell style: S-type tension/compression load cell
Load cell construction: alloy steel
Indicator: MNM LP7515 digital weighing indicator
Primary operating modes: tension, compression, suspended weighing and peak-load capture
Common units: lb, kg and oz through the LP7515 interface
Included system hardware: load cell, digital indicator, power supply and eye-bolt hardware
System is calibrated before shipment for the supplied load-cell/indicator combination
What Is an S-Type Load Cell and Why Is It Useful at 20,000 lb?
An S-type load cell gets its name from the S-shaped body of the sensor. The center section is engineered to deform by a tiny, controlled amount when force is applied through the threaded ends. Bonded strain gauges convert that microscopic deformation into an electrical signal. The indicator excites the bridge circuit, measures the millivolt-level output and converts it into a weight or force value on the display.
Unlike a platform scale load cell that is normally mounted under a deck, an S-type cell works naturally in an inline load path. That makes it useful for hanging loads, pull testing, suspended bins, cable and wire tension, proof-load checks, lifting-device testing, material testing and other applications where force travels through two attachment points. Because the same sensor geometry can respond to force in either direction, it is also widely used in both tension and compression test fixtures.
Detailed MS-1-20K Load Cell Specifications
The 20,000 lb sensor used in this family is the MS-1-20K alloy-steel S-type load cell. These electrical and performance specifications matter because they describe how stable, repeatable and compatible the sensor is—not just its maximum capacity.
Rated output: 3.00 ± 0.010 mV/V. A 3 mV/V load cell produces roughly 3 millivolts of signal per volt of excitation at full rated load, giving the indicator a strong measurement signal for industrial weighing.
Nonlinearity: ±0.02% of full scale. This describes the maximum departure of the sensor output from an ideal straight-line response over its measurement range.
Hysteresis: ±0.02% of full scale. Hysteresis describes the difference between readings reached while loading versus unloading through the same point.
Repeatability: ±0.01% of full scale. Repeatability indicates how closely repeated applications of the same load agree under similar conditions.
Creep over 30 minutes: ±0.02% of full scale. Creep describes the small change in output that can occur while a constant load remains applied.
Zero balance: ±1.00% of full scale.
Temperature effect on zero: ±0.02% FS per 10°C.
Temperature effect on output: ±0.02% FS per 10°C.
Input resistance: 385 ± 15 ohms.
Output resistance: 350 ± 5 ohms.
Insulation resistance: at least 5,000 megohms.
Recommended excitation: 10 V AC or DC.
Compensated temperature range: -10°C to 50°C (14°F to 122°F).
Operating temperature range: -20°C to 60°C (-4°F to 140°F).
Safe overload: 120% of full scale. For a 20,000 lb sensor this specification corresponds to 24,000 lb, but normal operations should still be designed around the rated 20,000 lb capacity rather than using overload margin as working capacity.
Load-cell cable: approximately 20 ft on the MS-1-20K specification.
Wire color code: red = excitation positive, black = excitation negative, green = signal positive, white = signal negative.
Understanding the 20,000 lb x 1 lb Resolution
The Crane-20k is configured to display a 20,000 lb maximum load in 1 lb increments. That is 20,000 displayed counts across the usable capacity. For heavy fabrication, proof testing, suspended material weighing and large-force applications, 1 lb resolution gives the operator substantially more detail than common 5 lb, 10 lb or 20 lb crane-scale increments.
Resolution should not be confused with complete system uncertainty. Real-world measurement quality also depends on calibration, mounting alignment, side loading, temperature, vibration, mechanical hardware and the way the force is introduced into the sensor. The benefit of a 1 lb display increment is that the electronics do not force the operator to round a 20,000 lb test into coarse steps.
The MNM LP7515 Digital Indicator
The LP7515 is the user interface for the system. Instead of trying to read a display attached directly to a suspended load, the load cell sends its electrical signal to a separate indicator. That lets the operator position the display where it is easier to see and operate.
Six-digit backlit LCD display for indoor or lower-light visibility.
Selectable lb, kg and oz units.
Zero and tare functions for establishing a working zero or removing fixture/container weight where appropriate.
Hold function for freezing a stable reading on the display.
Peak-hold use is particularly valuable for pull tests, break tests and dynamic loading where the highest force matters more than the final unloaded value.
Low-battery warning, idle mode and automatic power-off features help conserve portable power.
RS232 serial output supports compatible PCs, remote displays or data systems when configured correctly.
Quick-disconnect load-cell connection simplifies service and setup.
LP7515 Zero, Tare and Hold Ranges
The LP7515 manual specifies a tare range from approximately 2% to 100% of configured maximum capacity, an initial-zero range of ±10% of capacity and a manual-zero range of ±2% of capacity. Those ranges are important during installation because a tension fixture, shackle assembly or test frame can introduce dead load before the actual test force is applied. Proper calibration and tare/zero procedures let the indicator separate fixture weight from the force the operator wants to measure.
Load Cell Wiring and Indicator Connection
A four-wire strain-gauge load cell has two excitation wires and two signal wires. The indicator sends a regulated excitation voltage through the bridge and reads the differential signal returned on the signal pair. For the MS-1-20K color code, red is +excitation, black is -excitation, green is +signal and white is -signal. Correct polarity matters: reversed signal wiring can make the displayed force move in the wrong direction, while incorrect excitation wiring can prevent proper operation.
The LP7515 manual describes support for up to four 350-ohm load cells on compatible configurations. The Crane-20k package uses one S-type sensor, so its wiring is simpler than a four-cell floor scale. Protect the cable from crushing, sharp bends, moving hooks and abrasive surfaces because cable damage can cause unstable readings or intermittent signal loss even when the load cell itself is undamaged.
Best Applications for a 20,000 lb Tension/Compression Scale
A 20,000 lb S-type system fills the space between small bench-force gauges and permanently installed large-capacity industrial scales. Typical applications include:
Fabrication and welding shops: proof-checking fabricated lifting points, assemblies, fixtures and structural components.
Rigging and lifting operations: weighing suspended loads or verifying force in a controlled test setup.
Manufacturing quality control: checking pull force, assembly force, clamp force or product breakaway force.
Agriculture and ranch operations: suspended weighing of feed, bulk bags, equipment or materials where a platform scale is impractical.
Cable, rope and wire testing: measuring static tension or peak pull force within the system capacity.
Industrial maintenance: portable force measurement during equipment setup, repair, alignment and testing.
Test stands and fixtures: integrating the S-type cell into custom compression or tension frames.
Why Peak Hold Matters
Many force measurements happen too quickly for an operator to watch the exact maximum value in real time. A cable may snap free, a press may reach its maximum force and immediately retract, or a suspended load may briefly peak as movement stops. Peak hold captures the highest measured value so the operator can read it after the event. That is one of the most important differences between a simple hanging scale and a system intended for test or force-measurement work.
Recommended Setup Procedure
Inspect the sensor, cable, threaded attachments, indicator and power components before installation. Do not use damaged hardware.
Install attachment hardware so the force passes through the centerline of the S-type load cell. Side loads, bending moments and twisting can reduce accuracy and can mechanically stress the sensor.
Connect the load cell to the LP7515 indicator with the system unloaded.
Power the indicator and allow the reading to stabilize. Confirm the display returns to zero with no test load applied.
Apply a small known load first. Confirm the displayed direction and response before progressing to higher force.
For critical work, verify the system with traceable test weights or a suitable force standard at multiple points across the working range.
Use the hold or peak-hold mode that matches the application, and document the test procedure so repeated measurements are performed consistently.
Calibration and Accuracy: What the User Should Know
MNM Scales sells the Crane-20k as a calibrated load-cell and indicator package. Calibration links the electrical output of the MS-1-20K sensor to the digital value displayed by the LP7515. Because the load cell output is only a few millivolts per volt at full load, the indicator must know the correct zero point, span and capacity parameters to translate that signal accurately.
A calibration should be checked after significant mechanical changes, impact, overload, repair, load-cell replacement or indicator replacement. Organizations with quality systems may also establish scheduled verification intervals based on use, environment and required measurement confidence. For a 20,000 lb system, a verification plan using multiple points—rather than checking only zero and one load—provides much better information about the full measurement range.
Tension vs. Compression Use
In tension, the load cell is pulled from opposite ends. Examples include a suspended load, cable pull test or fixture that stretches the sensor inline. In compression, the force pushes through the sensor in the opposite direction. Both modes require a fixture that keeps force centered through the load cell. Compression setups especially need careful mechanical design so the cell is not exposed to side thrust or bending.
Troubleshooting Unstable or Incorrect Readings
Reading drifts slowly with a constant load
Check whether the system is still mechanically settling, whether temperature is changing, and whether the load has been applied long enough for load-cell creep to become visible. The MS-1-20K creep specification is ±0.02% FS over 30 minutes, so long-duration tests should use a consistent timing procedure.
Display jumps or fluctuates
Look for vibration, moving loads, damaged cable, loose connectors, electrical interference or a fixture that is rubbing against another structure. A suspended load that is swinging will naturally create a changing force even when its static weight is constant.
Weight changes in the wrong direction
Signal polarity may be reversed. On the MS-1-20K, green is signal positive and white is signal negative. Wiring should only be changed with power removed and by someone familiar with load-cell instrumentation.
System does not return to zero
Verify that no mechanical load remains on the cell, attachments are not binding, the cable is not pulling on the sensor and the indicator is within its permitted zero range. Persistent zero shift after impact or overload should be investigated before further high-load use.
RS232 output does not communicate
Confirm the correct cable, port wiring, baud rate, data format and indicator communication settings. RS232 problems are commonly configuration issues rather than weighing problems.
Safety Considerations for 20,000 lb Force Measurement
At 20,000 lb, the mechanical setup matters as much as the electronics. Every eye bolt, shackle, hook, pin, fixture, support, lifting device and structural attachment in the force path must be selected and used appropriately for the application. Never assume that an accessory is safe simply because the load cell itself is rated for 20,000 lb. The weakest mechanical component controls the safe capacity of the complete setup.
Keep personnel out of the line of force whenever a component is being proof-tested or pulled near its limit. Use guards, barriers or remote observation where a failure could release stored energy. Do not use the 120% safe-overload specification as permission to routinely exceed the 20,000 lb rated capacity.
Who Should Choose the 20,000 lb x 1 lb Version?
This configuration is a strong fit when your expected loads approach several tons but you still want 1 lb display increments. If most loads are only a few hundred pounds, a smaller-capacity S-type system can provide a better match and may offer finer useful resolution. If the application routinely approaches 20,000 lb, choosing a higher-capacity model may provide more operational headroom. Capacity selection should be based on the highest realistic applied force, including fixtures, shock and dynamic loading—not only the average load.
Frequently Asked Questions
What is the capacity of the MNM Scales Crane-20k?
The system is configured for a maximum weighing capacity of 20,000 lb with 1 lb displayed increments.
Can the Crane-20k measure both tension and compression?
Yes. The S-type load-cell geometry is designed for inline tension and compression measurement when installed in an appropriate fixture.
Does it include a digital indicator?
Yes. This MNM Scales package includes the LP7515 digital weighing indicator and power supply along with the load cell and attachment hardware.
What is peak hold used for?
Peak hold captures the highest force reached during a test or dynamic loading event, which is useful for pull tests, proof tests and breakaway-force measurements.
What is the rated output of the MS-1-20K load cell?
The MS-1-20K is specified at 3.00 ± 0.010 mV/V rated output.
What is the safe overload rating?
The MS-1-20K load-cell specification lists safe overload at 120% of full scale. The normal working capacity of the Crane-20k remains 20,000 lb.
Can the LP7515 connect to a computer?
The indicator supports RS232 serial output. Integration requires compatible cabling and matching communication settings on the receiving device.
How long is the load-cell cable?
The MS-1-20K load-cell specification lists a 20 ft cable, allowing the digital indicator to be positioned away from the sensor and load point.
Is the system calibrated before shipment?
Yes. The Crane-20k listing describes the load-cell and indicator system as calibrated and tested before shipment so it arrives configured for its rated capacity and increment.
Where can I get help choosing or setting up the system?
For product, application or configuration questions, contact MNM Scales at (832) 290-3120 or mnmscales@yahoo.com. Describing the maximum force, whether the application is tension or compression, how the load will be attached and whether data output is required will help identify the right setup.
Final Takeaway
The MNM Scales Crane-20k is more than a 20,000 lb sensor. It is a complete high-capacity force-weighing package that combines the MS-1-20K alloy-steel S-type load cell, a separate LP7515 digital indicator, 1 lb display resolution, peak-hold capability and calibration into one system. Its value is strongest in applications where a normal platform scale cannot get into the load path and where the operator needs to see, hold or record a large tension or compression force from a convenient location.
For help with capacity selection, mounting, replacement parts, calibration or a specific industrial weighing application, call MNM Scales at (832) 290-3120 or email mnmscales@yahoo.com.
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