OHAUS Navigator® NV621ZH Portable Precision Balance
| Brand | OHAUS |
|---|---|
| Origin | Jiangsu, China |
| Manufacturer Type | Manufacturer |
| Product Category | Domestic |
| Model | NV621ZH |
| Instrument Type | General-Purpose Portable Balance |
| Maximum Capacity | 620 g |
| Readability | 0.1 g |
| Repeatability | ±0.1 g |
| Calibration Method | External |
| Overload Protection | Up to 400% of max capacity (2480 g) |
| Transport Lock | Integrated mechanical sensor lock |
| Operating Environment | 10–40 °C, ≤80% RH non-condensing |
Overview
The OHAUS Navigator® NV621ZH is a robust, entry-level portable precision balance engineered for reliability and operational consistency across diverse non-regulated weighing environments. It operates on electromagnetic force restoration (EMFR) principle—where load-induced displacement of the weighing pan is counteracted by a precisely controlled electromagnetic current—and converts this signal into a stable digital mass reading with 0.1 g resolution. Designed for routine mass determination tasks rather than analytical or micro-weighing applications, the NV621ZH delivers high reproducibility under standard ambient conditions (10–40 °C, ≤80% RH non-condensing). Its compact footprint, integrated carrying handle, and battery-powered operation (optional AC adapter support) make it suitable for field use, production line checks, educational labs, and quality control stations where portability and rapid stabilization are prioritized over sub-milligram sensitivity.
Key Features
- Electromagnetic force restoration (EMFR) sensor architecture ensures consistent linearity and long-term stability without mechanical wear.
- Four-fold overload protection (up to 2480 g) safeguards the load cell from accidental overloading during handling or material dumping—critical in industrial and teaching lab settings.
- Integrated transport lock mechanically immobilizes the sensor during transit, preventing damage to the delicate suspension system and preserving calibration integrity.
- Stabilization time ≤1 second under typical loading conditions enables efficient throughput in repetitive weighing workflows.
- Large, backlit LCD display with intuitive icon-driven interface supports operation without extensive training; unit toggling (g, oz, ct, etc.) and simple tare functionality are accessible via front-panel keys.
- IP42-rated enclosure provides basic protection against dust ingress and vertical dripping water—suitable for clean but non-sterile environments such as prep rooms or warehouse staging areas.
Sample Compatibility & Compliance
The NV621ZH accommodates samples up to 620 g with dimensions compatible with standard 120 mm diameter weighing pans (pan not included). It supports containers of moderate height and weight (e.g., beakers, weigh boats, plastic trays) without interference from side draft or vibration when placed on a level, rigid surface. While not certified for GLP/GMP-regulated environments requiring audit trails or 21 CFR Part 11 compliance, the balance meets general-purpose metrological requirements outlined in OIML R76-1 (non-automatic weighing instruments, Class III) for commercial and educational use. No internal calibration mechanism is present; external calibration using traceable weights (e.g., ASTM E617 Class M2 or better) is required prior to first use and at user-defined intervals per local SOPs.
Software & Data Management
The NV621ZH does not feature built-in data logging, USB/RS232 connectivity, or PC interface capabilities. All measurements are displayed and retained only on the unit’s screen until overwritten by the next weighing event. For documentation purposes, users must manually record values or integrate the balance into third-party systems via optional serial-to-USB adapters (not supplied) and terminal emulation software. No firmware updates or configuration utilities are provided by OHAUS for this model, reflecting its positioning as a standalone, low-maintenance instrument intended for environments where regulatory traceability is not mandated.
Applications
- Raw material receipt verification in light manufacturing and food processing facilities.
- Batch ingredient dispensing in formulation labs and pilot-scale production units.
- Student laboratory exercises involving gravimetric analysis, solution preparation, and density estimation.
- Inventory counting and parcel weighing in logistics and distribution centers.
- Field-based environmental sampling where battery operation and shock resistance are essential.
- Workshop and maintenance operations requiring quick verification of component mass before assembly or replacement.
FAQ
What is the maximum sample weight the NV621ZH can measure?
The NV621ZH has a maximum capacity of 620 g with 0.1 g readability. Exceeding this limit—even momentarily—may trigger the overload protection circuit and requires recalibration after removal of excess load.
Does this balance support internal calibration?
No. The NV621ZH requires external calibration using certified reference weights. Internal calibration is not supported.
Can the NV621ZH be used in a fume hood or near ventilation sources?
Not recommended. Air currents exceeding 0.2 m/s may impair stabilization and repeatability. Use only on stable, vibration-isolated surfaces away from HVAC outlets or open windows.
Is the battery rechargeable, and what is its typical runtime?
It uses four AA alkaline batteries (included), providing approximately 100 hours of continuous operation. Rechargeable NiMH batteries are compatible but may reduce total runtime due to lower nominal voltage.
What environmental conditions affect measurement accuracy?
Ambient temperature fluctuations >2 °C/hour, relative humidity >80% RH, or static charge buildup on samples or containers can introduce drift or erratic readings. Allow the unit to acclimate for ≥30 minutes after power-on or environmental change.
