HBM PW6DC3MR Single Point Load Cell

PW6DC3MR/XXkg

PW6D: Serie di prodotti, single-point type optimized for high-speed dynamic weighing

C3: Accuracy class of 3,000 verification divisions in accordance with OIML R60

MR = Multi-Range: Compared with standard C3 version, it supports a smaller minimum verification interval, suitable for multi-range weighing instruments

XXkg: Capacità nominale (3/5/10/15/20/30/40kg)

Complete ordering model example: 1-PW6DC3MR/10KG-1

2. Specifiche principali
3. Capacity Options

3kg, 5kg, 10kg, 15kg, 20kg, 30kg, 40kg

2. Parametri Elettrici

Potenza nominale: 2.0 mV/V

Bridge Input Resistance: ~350 Ω

Tensione di eccitazione consigliata: 5～12 V DC (Massimo. 15 A DC)

Costruzione: 6-wire design (cable can be trimmed) to eliminate measurement error caused by cable voltage drop; compatible with 4-wire instruments

Resistenza di isolamento: >2000 MΩ

3. Precisione & Certificazioni

OIML R60 C3MR, nLC=3000 divisions

Off-center load compensation compliant with OIML R76; maximum platform dimension for single load cell: 300×300 mm

Non linearità / Isteresi / Ripetibilità: ≤±0.017 %FS

4. Meccanico & Specifiche ambientali

Materiale: Lega di alluminio

Classe di protezione: IP67

Rated Deflection: 0.18～0.29 mm (High stiffness, risposta dinamica veloce)

Compensated Temperature Range: -10 ℃ ～ +40 ℃

Intervallo di temperatura operativa: -10 ℃ ～ +50 ℃

Sovraccarico sicuro: 150%FS; Ultimate Overload: 300%FS

Mounting Bolt: M6; Recommended Tightening Torque: 10 N·m

3. Vantaggi principali

✅ Optimized for dynamic weighing: High natural frequency, ideal for high-speed checkweighing and volumetric filling

✅ Built-in off-center load compensation to minimize platform eccentricity error

✅ IP67 sealing, applicable in dusty and humid production environments

✅ 6-wire shielded cable ensures stable signal for long-distance wiring

✅ MR multi-range variant supports smaller verification intervals, compliant for legally verified commercial weighing equipment

4. Applicazioni tipiche

Inline checkweighers, weight sorting machines

Small-scale automatic packaging, polvere & particle filling equipment

Industrial platform scales, multi-head combination weighers

Dynamic weight monitoring on automated production lines

5. Definizione di cablaggio (Standard 6-Wire Shielded Cable)

For 4-wire instruments: Short-circuit +Sense to +Exc, and -Sense to -Exc

6. Stessa serie & Alternative References
7. PW6DC3: Standard C3 accuracy (non-MR), costo inferiore, cannot support multi-range small verification intervals
8. PW2DC3MR: Smaller-size single-point load cell from HBM, with smaller maximum allowable platform size
9. Alternative domestiche: Single-point C3 load cells from Zemic, UN&D, Zhonghang Electronic Measuring Instruments. Verify mounting hole layout, mV/V rating and maximum platform size before replacement.
10. Precauzioni per l'installazione
11. Mounting surfaces must be flat and rigid. Do not weld or strike the load cell body.
12. Tighten M6 bolts strictly at 10 N·m to avoid thread stripping on aluminum housing.
13. Load shall be applied vertically downward; avoid lateral force and torque impact.
14. Prevent mechanical bending and tension at the cable outlet; single-end grounding is recommended for shielding.

Complete Load Cell Selection Guide (Illustrated with HBM PW6DC3MR Single-Point Load Cell)

Fare un passo 1: Confirm Mechanical Structure Type (Highest Priority)

Match load cell structure according to load condition:

Hard restriction of PW6DC3MR: Maximum platform dimension: 300×300 mm. Platform exceeding this size will cause excessive eccentricity error.

Fare un passo 2: Calcolo della capacità (Most Common Pitfall in Selection)

Formula di calcolo

Rated Capacity of Load Cell ≥ (Platform Dead Weight + Maximum Product Weight) × Safety Factor

Stable static weighing: Safety factor 1.2～1.3

Dynamic checkweighing, material drop impact, vibrating production line: 1.5～2.0 (1.5 raccomandato)

Esempio pratico (PW6DC3MR)

Platform dead weight = 1.5kg, maximum product weight = 10kg, inline dynamic checkweighing:

Total load = 1.5 + 10 = 11.5kg; 11.5 × 1.5 = 17.25kg

Priority selection: PW6DC3MR/20KG. Avoid 15kg (insufficient margin) and excessive 30kg capacity (poor resolution for light loads).

⚠️ Two critical rules:

1. Do not operate continuously near full capacity;
2. Do not oversize capacity excessively, which degrades resolution for low-weight measurement.

Fare un passo 3: Accuracy Class Selection (C3 / C3MR / C6 Comparison)

Take HBM PW6D series as example:

1. C3: Standard 3000 divisions, for general industrial weighing, unable to achieve ultra-small verification intervals
2. C3MR (Il tuo modello): Multi-Range variant, OIML R60 certified, supports smaller minimum verification interval (Vmin)

✅ Suitable for equipment requiring legal metrology certification, high-speed checkweighing, volumetric filling and high display resolution (gram-level measurement)

3. C6: 6000 divisions, maggiore precisione, costo più elevato, stricter requirements for mounting rigidity and operating environment

Quick Selection Rule for C3 vs C3MR

Equipment requires commercial metrological certification, high-precision checkweighing, small scale interval (gram level) → PW6DC3MR

Only internal process monitoring, no weighing certification required, loose accuracy requirements → PW6DC3 (versione standard)

Key accuracy indicators to review: Non linearità, isteresi, ripetibilità, creep, temperature drift error.

Fare un passo 4: Ambiente operativo, Materiale & Classe di protezione

1. Materiale

PW6DC3MR: Lega di alluminio; suitable for dry standard food and automated workshops.

For washdown, humid or corrosive / salt spray environments: Prefer stainless steel single-point load cells.

2. Classe di protezione

PW6D: IP67, dust-proof and splash-proof; NOT for permanent submersion.

For fully washed equipment or underwater installation: IP68 hermetically sealed load cells are required.

3. Intervallo di temperatura

Compensated range: -10～+40℃; prolonged operation outside this range leads to severe zero drift. Custom wide-temperature models needed for extreme temperature conditions.

4. Explosion Protection: For hazardous explosive areas, use intrinsically safe certified load cells. Standard PW6DC3MR is non-explosion-proof.

Fare un passo 5: Electrical Parameter Matching with Instrument

1. Sensibilità: PW6DC3MR = 2.0 mV/V, the most common specification for industrial weighing; confirm instrument compatibility.
2. Tipo di cablaggio: PW6D adopts 6-wire (with Sense feedback lines)

Instrument supporting 6-wire: Full wiring to eliminate cable voltage drop

Instrument only supporting 4-wire: Short-circuit +Sense to +Exc, -Sense to -Exc

3. Excitation Voltage: Recommended 5～12 V DC, massimo 15 A DC
4. Bridge Resistance: ~350 Ω input resistance, compatible with standard weighing transmitters

Fare un passo 6: Mechanical Dimension Verification (Easily Overlooked)

1. Lunghezza totale, altezza, mounting hole pitch, thread specification (PW6D uses M6 mounting bolts)
2. Check mechanical installation space
3. Ensure vertical load transmission; structure design shall eliminate lateral force and torque

PW6D mounting torque standard: M6 bolt tightening torque 10 N·m. Aluminum housing risks thread damage under excessive torque.

Fare un passo 7: Distinguish Dynamic / Static Application Scenarios

Static Weighing (Warehouse Platform Scale): Standard C3 is sufficient; prioritize long-term zero stability

Dynamic Weighing (Inline Checkweigher, Online Sorting): PW6DC3MR preferred; optimized high natural frequency, fast response and vibration resistance

Common Selection Mistakes Checklist

❌ Only consider maximum product weight without including platform dead weight

❌ Use PW6D single-point load cell for platform larger than 300×300 mm, resulting in excessive eccentricity error

❌ Adopt safety factor of only 1.2 under dynamic impact, leading to elastic element fatigue and permanent damage

❌ Purchase standard C3 instead of C3MR when weighing certification is required, failing to meet minimum scale interval requirement

❌ Select aluminum IP67 load cell for washdown humid environment, leading to long-term water ingress and premature failure

❌ Oversized capacity causes unstable readings and poor resolution for light products

Quick Selection Template (Ready for Direct Use)

1. Struttura: Single-Point ✅ (Platform ≤300×300 mm)
2. Total Load: Platform ____kg + Max Product ____kg = ____kg × Safety Factor ____ = ____kg → Selected Model PW6DC3MR/____kg
3. Precisione: Metrological certification required? Yes → C3MR; No → C3
4. Ambiente: Dry workshop, IP67 acceptable; Lavaggio / corrosive environment → switch to stainless steel load cell
5. Elettrico: Instrument supports 2.0 mV/V; confirm 6-wire or 4-wire wiring
6. Installazione: Verify dimension, M6 mounting space, vertical force transmission structure

How to Determine the Mounting Position of Load Cells

Explanation based on HBM PW6DC3MR single-point load cell (single-cell platform); general rules for multi-cell weighing platforms are also included.

1. Distinguish Two Structural Types: Single-Point vs Multi-Cell

(1) Single-Point Load Cell (PW6DC3MR, single cell supporting one platform)

Single-point load cells feature built-in off-center load compensation.

Standard mounting position: Geometric center of the platform bottom

✅ Optimal arrangement:

Align the load-bearing hole center of the load cell with the length and width center of the platform.

Maximum allowable platform dimension: 300 × 300 mm (PW6D specification limit)

⚠️ Critical Restrictions:

If the load cell deviates from the center:

Eccentricity error increases

Inconsistent readings when weight is placed at four corners

Even centered installation cannot compensate error if platform exceeds manufacturer’s maximum dimension limit

Practical method: Draw two diagonals of the rectangular platform; the intersection is the center mounting position.

(2) Multi-Cell Structure (3/4 Cantilever/Shear Beam Load Cells, Platform Scales, Storage Hoppers)

Mounting position follows the principle of even load distribution according to center of gravity

1. Rectangular platform with four load cells: Symmetrically arranged near four corners
2. Circular storage bin with three load cells: Evenly distributed in an equilateral triangle layout
3. Target: Load carried by each load cell shall be as uniform as possible under empty and full load conditions
4. Five Universal Principles for All Weighing Systems

Principio 1: The combined center of gravity must fall within the support envelope of load cells

1. Unloaded condition: Platform self-weight center of gravity lies within the support area
2. Fully loaded condition: When material is placed at maximum eccentricity, the overall combined center of gravity remains within the support envelope

If the center of gravity moves outside the support region: Risk of platform tipping, and the load cell bears huge lateral force and torque, leading to permanent damage.

Principio 2: Eliminate Lateral Force and Torque on Load Cells

Load cells shall only bear vertical compressive force

❌ Prohibited conditions:

Lateral component force generated by skewed mounting position

Torque induced by insufficient rigidity of support frame

✅ Soluzione:

Design mechanical stops for horizontal restriction. Maintain tiny vertical clearance; stops shall not carry vertical load.

Principio 3: Ensure Vertical Force Transmission

The load-bearing surface of the load cell must be parallel to the bottom surface of the weighing platform.

Mounting base must be flat and rigid; avoid thin plate suspension and local concentrated contact.

PW6DC3MR aluminum housing forbids point contact loading.

Principio 4: Avoid Strong Vibration Sources and Thermal Expansion Tension

Mounting position selection:

Keep distance from strong vibration sources such as motors and conveyor rollers

Thermal expansion/contraction of long frames may pull the load cell; sliding support structure is required when necessary

Principio 5: Prevent Tensile Stress on Cable Outlet

The cable outlet of PW6DC3MR is at the end of the sensor.

Arrangement requirement: Reserve slack cable loops; avoid tension and repeated bending at the cable root to prevent internal wire breakage.

3. Step-by-Step Positioning for Single-Point Platform (PW6DC3MR)
4. Measure external platform dimension: Length L × Width W
5. Calculate center coordinates: L/2, W/2
6. Align the load-bearing hole center of the load cell with the calculated center point
7. Platform dimension verification:

≤300×300 mm: Normal centered installation

>300×300 mm: PW6D cannot be used. Switch to larger single-point load cell or multi-cell solution

5. Weight test verification:

Place calibration weights sequentially at four corners of the platform and observe reading deviation.

Excessive four-corner error indicates either offset load cell position or oversize platform.

4. Four-Corner Positioning Operation for Multi-Cell Platform (4 Load Cell Example)
5. Symmetric layout; four support points form a rectangle
6. Leave proper margin between support points and platform edge; avoid placing too close to edges
7. Rough leveling under empty load with preloading
8. Perform four-corner error calibration after loading weights at each corner
9. Install mechanical stops to prevent platform sliding under impact
10. Common Mounting Position Errors
11. Single-point load cell installed away from platform center → inconsistent readings at four corners
12. Oversize platform still using PW6D single-point load cell → excessive eccentricity error
13. Insufficient rigidity of support frame; frame deformation under load induces torque on load cell
14. Locked mechanical stops; thermal expansion creates additional force leading to continuous zero drift
15. Load cells arranged too close to edges; center of gravity moves outside support envelope when material is placed eccentrically
16. Belt tension creates horizontal pulling force transferred to load cell on inline checkweighers (Independent frame required to isolate belt tension)
17. Additional Advice for Your Equipment (Checkweigher with PW6DC3MR)

For inline checkweighers: The belt conveyor frame shall not be rigidly fixed to the weighing platform.

Conveyor motor and belt tension produce continuous horizontal pulling force.

Recommended solution: Only the weighing platform carries products; the conveyor frame stands independently on the ground to isolate horizontal force.