Yoke FB503 Precision Balance
| Brand | Yoke |
|---|---|
| Origin | Shanghai, China |
| Manufacturer | Yoke Instrument Co., Ltd. |
| Type | Precision Balance |
| Capacity | 500 g |
| Readability | 1 mg |
| Calibration | External |
| Repeatability | ±1 mg |
| Accuracy Class | Class II (per OIML R76) |
| Pan Diameter | 90 mm |
| Dimensions (W×D×H) | 360 × 220 × 350 mm |
| Net Weight (incl. packaging) | 7.5 kg |
| Power Supply | DC 9 V / 1 A |
Overview
The Yoke FB503 Precision Balance is an OIML Class II-certified analytical-grade weighing instrument engineered for laboratories requiring reliable 1 mg readability across a 500 g capacity range. It operates on electromagnetic force compensation (EMFC) principle—where the mass-induced displacement of a precision load cell is counterbalanced by a controlled electromagnetic current, enabling high-resolution, drift-resistant measurement without mechanical levers or knife-edges. Designed for routine QC testing, formulation verification, sample preparation, and educational applications, the FB503 delivers stable performance under standard ambient conditions (20 ± 5 °C, < 80 % RH non-condensing) and meets fundamental metrological requirements for traceable mass measurement in non-regulated and GLP-aligned environments.
Key Features
- High-stability electromagnetic sensor system with CNC-machined core components ensuring long-term linearity and thermal drift resistance;
- ARM32-bit microprocessor architecture enabling real-time digital filtering, adaptive response time adjustment, and noise suppression without compromising resolution;
- Integrated draft shield enclosure with ergonomic sliding doors—designed to minimize air currents while maintaining full accessibility during operation;
- Multi-function weighing modes including piece counting (PCS), checkweighing (CHK), density determination (with optional sinker kit), and animal/dynamic weighing with auto-hold stabilization;
- SMT-assembled PCBs with conformal coating for enhanced ESD and humidity resistance, supporting continuous operation in shared lab environments;
- Backlit BTN black-on-gray LCD display (character height: 8.5 mm) optimized for legibility under varied lighting conditions and at viewing angles up to ±45°;
- External calibration capability using certified weights traceable to national standards (e.g., NIST, PTB, or BIPM); supports calibration verification per ISO/IEC 17025 clause 6.5.2.
Sample Compatibility & Compliance
The FB503 accommodates samples up to 500 g on its 90 mm stainless steel weighing pan, suitable for solid powders, granules, pre-weighed vials, filter papers, and small-volume liquid containers (with tare container). Its Class II accuracy classification complies with OIML R76-1 (2017) and EN 45501:2015 for non-automatic weighing instruments. While not FDA 21 CFR Part 11–compliant out-of-the-box (lacking electronic signature and audit trail functionality), the balance supports documented calibration and operational qualification when integrated into laboratory SOPs aligned with ISO/IEC 17025, USP , and EU GMP Annex 11 frameworks. Environmental suitability conforms to IP32 rating (dust-protected, drip-resistant).
Software & Data Management
The FB503 features a standard RS232 interface (DB9 male) compatible with Windows/macOS/Linux systems for direct data logging into LIMS, ELN, or spreadsheet applications. Optional YokeCom software enables configurable output formatting (e.g., CSV, tab-delimited), timestamping, unit conversion (g, oz, ct, carat), and batch ID tagging. All data transmissions are ASCII-based with no proprietary drivers required. The device does not store historical measurements internally; however, external recording ensures full traceability when paired with validated acquisition tools. For regulated labs, integration with third-party 21 CFR Part 11–compliant middleware (e.g., LabArchives, Benchling) is supported via serial protocol documentation available upon request.
Applications
- Pharmaceutical: Excipient and API weighing for tablet formulation, capsule fill checks, and stability study sample preparation;
- Chemical & Materials Science: Catalyst dosage, polymer blend ratio verification, and catalyst loading consistency checks;
- Food & Agriculture: Nutrient premix batching, moisture content determination (via loss-on-drying workflows), and portion control QA;
- Academic & Training Labs: Fundamental metrology instruction, density experiments (Archimedes’ principle), and statistical process control exercises;
- Environmental Testing: Filter weight gain analysis for particulate matter (PM10/PM2.5) monitoring per EPA Method 201A guidelines.
FAQ
What calibration weights are required for the FB503?
A certified 500 g Class M2 or better external weight is required for full-span calibration. Verification at intermediate points (e.g., 50 g, 200 g) is recommended per ISO/IEC 17025 calibration interval policies.
Does the FB503 support internal calibration?
No—it is externally calibrated only. Internal motorized calibration is not implemented in the FB series to maintain cost-efficiency and mechanical simplicity.
Can the FB503 be used in a fume hood?
Yes, provided the hood’s face velocity is ≤0.5 m/s and turbulence is minimized; the draft shield must remain fully closed during weighing.
Is the display readable under bright laboratory lighting?
Yes—the high-contrast BTN LCD with white LED backlight maintains clarity under both fluorescent and LED ambient illumination.
What is the warm-up time before first use?
Minimum 30 minutes at stable room temperature (20 ± 2 °C) is recommended to achieve thermal equilibrium of the EMFC sensor and ensure optimal repeatability.
