Guance Instruments GEST-121A.22 Automatic Insulation Resistance & Resistivity Tester
| Brand | Guance Instruments |
|---|---|
| Origin | Beijing, China |
| Manufacturer Type | Authorized Distributor |
| Country of Origin | China |
| Model | GEST-121A.22 |
| Price | USD 2,100 (FOB Beijing) |
Overview
The Guance Instruments GEST-121A.22 Automatic Insulation Resistance & Resistivity Tester is a precision digital instrument engineered for the quantitative determination of electrical insulation properties in solid, liquid, and semi-solid dielectric materials. Based on the constant-voltage DC measurement principle compliant with ASTM D257, IEC 60093, and GB/T 1410–2006, the system measures volume resistivity (ρ), surface resistivity (σ), and insulation resistance (Rins) across a dynamic range of 1 × 10⁴ Ω to 2 × 10¹⁶ Ω — enabling characterization of low-conductivity polymers, elastomers, coatings, powders, gels, and insulating fluids. Its core architecture integrates a high-stability DC voltage source (10 V to 1000 V, adjustable in 10-V increments), guarded triaxial input circuitry, and a low-noise electrometer amplifier stage, minimizing leakage current errors and ensuring traceable metrological performance under controlled environmental conditions (23 ± 2 °C, 50 ± 5 % RH).
Key Features
- Wide measurement range: 10⁴ Ω to 2 × 10¹⁶ Ω with automatic range selection and real-time auto-zero compensation
- Programmable test voltage: 10 V – 1000 V DC, digitally regulated with ≤0.5 % output stability over 60 s
- Dual-mode operation: Simultaneous display of resistance (Ω), resistivity (Ω·cm), and leakage current (A) with 4½-digit resolution
- Guarded electrode interface supporting standardized electrode configurations per ASTM D257: concentric ring (surface resistivity), two-terminal (bulk), and three-terminal (volume + surface decoupling)
- Embedded Intel-based microcontroller platform enabling stable thermal drift compensation (<0.05 %/°C) and low-power standby mode
- Compact benchtop design (280 × 220 × 120 mm), weight <2.5 kg, suitable for ISO 17025-accredited labs and QC environments
Sample Compatibility & Compliance
The GEST-121A.22 accommodates diverse sample geometries via interchangeable electrode fixtures — including parallel-plate electrodes for rigid solids (e.g., PVC sheets, silicone rubber), liquid cells with Pt-black electrodes for insulating oils, and powder compression cells with stainless-steel pistons. Surface resistivity testing adheres to the guarded-electrode method specified in IEC 62631-3-1, while volume resistivity measurements follow the unguarded two-probe configuration defined in ASTM D257 Annex A3. All calibration procedures are traceable to NIM (National Institute of Metrology, China) standards, and the instrument supports GLP-compliant data recording when used with external timestamped logging systems. It meets CE marking requirements for electromagnetic compatibility (EN 61326-1) and safety (EN 61010-1).
Software & Data Management
While the GEST-121A.22 operates as a standalone unit with front-panel keypad and LCD display, it features an RS-232 serial interface (optional USB-to-serial adapter) for bidirectional communication with Windows-based PC software. The included Guance TestSuite v2.1 enables automated sequence programming (voltage ramping, dwell time, multi-point sampling), real-time graphing of R(t) decay curves, statistical analysis (mean, SD, CV%), and export to CSV or PDF formats. Audit trail functionality records operator ID, test date/time, voltage setting, electrode type, and environmental metadata — supporting FDA 21 CFR Part 11 readiness when deployed with validated user access controls and electronic signature modules.
Applications
- Quality control of polymer insulators in wire & cable manufacturing (e.g., cross-linked polyethylene, ETFE)
- Resistivity mapping of antistatic packaging films and ESD-safe work surfaces
- Stability assessment of transformer oils and capacitor-grade dielectric fluids per IEC 60296
- R&D screening of nanocomposite dielectrics (e.g., SiO₂/epoxy, BN/polyimide) for aerospace applications
- Regulatory compliance testing for medical device housings (IEC 60601-1 clause 8.8.3)
- Surface contamination evaluation on semiconductor wafer handling components
FAQ
What standards does the GEST-121A.22 comply with for resistivity measurement?
ASTM D257, IEC 60093, GB/T 1410–2006, and IEC 62631-3-1 for surface and volume resistivity testing.
Can the instrument measure both surface and volume resistivity simultaneously?
No — simultaneous measurement requires separate electrode configurations; however, the system supports rapid reconfiguration between surface-guarded and volume two-terminal setups.
Is calibration certificate included with shipment?
Yes — each unit ships with a factory calibration report traceable to NIM, valid for 12 months under normal operating conditions.
Does the tester support temperature-controlled measurements?
Not natively — ambient temperature control must be maintained externally per ASTM D257 Section 7.2; optional environmental chamber integration is supported via analog trigger I/O.
What maintenance is required for long-term accuracy?
Annual verification against certified reference resistors (10⁶ Ω to 10¹⁴ Ω) and periodic cleaning of electrode contacts with isopropyl alcohol is recommended.
