OHAUS GUARDIAN™5000 Advanced Heating Magnetic Stirrer

Overview

The OHAUS GUARDIAN™5000 Advanced Heating Magnetic Stirrer is an engineered solution for precise, reproducible thermal mixing in regulated laboratory environments. It operates on the principle of magnetic coupling—using a high-performance samarium-cobalt (SmCo) magnet rotor driven by a precisely controlled rotating magnetic field beneath a thermally stable ceramic heating surface. This architecture eliminates mechanical drive shafts, minimizing contamination risk and maintenance while enabling uniform heat distribution and consistent torque delivery across the full 22 L working volume. Designed for compliance-critical workflows—including GLP, GMP, and ISO/IEC 17025-accredited laboratories—the instrument integrates dual-sensor temperature monitoring (heating plate + Pt1000 probe), independent 3-point calibration capability, and audit-ready parameter logging via RS232 interface. Its operational envelope spans from ambient +5°C to 500°C, supporting applications ranging from gentle buffer equilibration to high-temperature solvent reflux preparation.

Key Features

• Robust all-metal housing with IP32 ingress protection and smooth, non-porous surface for rapid decontamination and routine cleaning.
• Ceramic square heating plate (26 cm × 26 cm) offering superior thermal homogeneity, chemical resistance, and long-term stability under repeated thermal cycling.
• High-torque SmCo magnetic drive system delivering consistent agitation up to 1,800 rpm with ±2% speed stability—even at low-viscosity or high-volume conditions.
• Dual-mode temperature control: programmable ramp-soak profiles and precision hold modes, with real-time deviation alerts and audible over-temperature alarm.
• Ergonomic front-panel design with 25° tilt angle, high-contrast backlit LCD, and intuitive rotary knob + keypad interface for glove-compatible operation.
• RS232 serial port enabling integration with LIMS, ELN, or custom SCADA systems for remote command execution, parameter logging, and time-stamped data export.
• Configurable timer (1 min – 99 h 59 min) with auto-shutdown and safety lockout functions to prevent unattended operation beyond defined limits.

Sample Compatibility & Compliance

The GUARDIAN™5000 accommodates standard laboratory glassware—including beakers, Erlenmeyer flasks, and jacketed reactors—up to 22 L capacity, provided appropriate stirring bars (e.g., PTFE-coated, elliptical, or cross-shaped) are selected for viscosity and geometry matching. Its ceramic surface resists corrosion from common solvents (e.g., acetone, ethanol, dilute acids/bases) and withstands incidental contact with sodium hydroxide or nitric acid solutions. The instrument meets CE and TÜV safety standards per EN 61010-1:2010 and EN 61326-1:2013. Temperature and speed parameters support traceable calibration against NIST-traceable references; calibration records—including date, operator ID, reference standard used, and deviation values—are retainable via RS232 export. For FDA-regulated environments, the device supports 21 CFR Part 11-compliant data integrity when paired with validated third-party software for electronic signature and audit trail management.

Software & Data Management

While the GUARDIAN™5000 operates as a standalone instrument with embedded firmware, its RS232 interface enables bidirectional communication using ASCII-based command protocols. Users may configure automated sequences—including multi-step temperature ramps, speed transitions, and timed shutdowns—via external terminal emulators or custom Python/Matlab scripts. All setpoints, actual readings, timestamps, and alarm events can be streamed in real time or logged at user-defined intervals (e.g., every 5 seconds). Exported CSV files contain ISO 8601-formatted timestamps, enabling alignment with chromatographic or spectroscopic datasets in centralized analytical data systems. Firmware updates are delivered via secure OHAUS-provided binaries and require physical USB-to-serial adapter connection—not network exposure—preserving air-gapped lab security policies.

Applications

• Preparation of culture media and buffered saline solutions requiring strict pH and temperature consistency during dissolution.
• Thermal activation of catalysts and polymerization initiators under controlled shear and thermal input.
• Accelerated stability testing of pharmaceutical formulations where simultaneous heating and mixing simulate accelerated aging conditions.
• Extraction protocols involving heat-assisted solid-liquid partitioning (e.g., Soxhlet alternatives) with volatile organic solvents.
• Calibration of reference thermometers and viscometers using standardized glycerol/water mixtures across defined temperature gradients.
• Pre-analytical sample homogenization for ICP-MS or HPLC sample introduction systems where particulate suspension uniformity directly impacts detection sensitivity.

FAQ

Does the GUARDIAN™5000 support external temperature probe feedback for closed-loop control?
Yes. When a Pt1000 probe is inserted into the sample vessel and connected to the rear-panel sensor port, the unit defaults to probe-controlled mode—using real-time sample temperature rather than heating plate surface temperature for regulation.
Can the instrument maintain ±0.5°C accuracy across its entire 5–500°C range?
Accuracy specifications apply under defined conditions: ±0.5°C is guaranteed below 100°C using the Pt1000 probe; above 100°C, probe accuracy degrades to ±0.5% of reading, and heating plate stability remains ±1% of setpoint.
Is the RS232 interface compatible with modern Windows/Linux systems without legacy drivers?
Yes. Standard FTDI or CP2102-based USB-to-serial adapters are fully supported; no proprietary drivers are required. Communication uses 9600 baud, 8-N-1 configuration with CR/LF line termination.
What maintenance is required to sustain long-term performance?
Annual verification of temperature and speed calibration is recommended. No routine lubrication or internal servicing is needed—the sealed SmCo motor and ceramic plate are designed for >10,000 hours of continuous operation.
How does the IP32 rating affect placement in fume hoods or humidified incubator rooms?
IP32 provides protection against vertically falling droplets and solid objects >2.5 mm. It permits use inside ventilated fume hoods but prohibits installation in condensing or high-humidity enclosures (e.g., CO₂ incubators) without supplemental environmental shielding.