The GW Instek GPM-8320 and GPM-8330 are digital power meters specifically designed for measuring power in three-phase AC power systems. They are ideal for a wide range of electrical and electronic product testing applications.

The GPM-8320 is equipped with two measurement modules, while the GPM-8330 features three modules. Both models provide a measurement bandwidth from DC to 100 kHz (0.1 Hz – 100 kHz), using 16-bit A/D converters and a 300 kHz sampling rate to ensure highly accurate measurements.

These instruments include a 5-inch TFT LCD display, 5-digit measurement resolution, and support up to 25 different power measurement parameters. Their high precision and advanced capabilities make them among the most fully featured and cost-effective power meters in their class.

Key Features

• Waveform display for voltage, current, and power
• Integration measurement function
• Multi-order harmonic measurement and analysis
• Compliance with IEC61000-4-7 for 50/60 Hz harmonic measurements
• External sensor input terminals
• Multiple communication interfaces

These capabilities allow users to perform clear, convenient, and highly accurate power measurements.

Wiring Configurations and Measurement Accuracy

The GPM-8320/8330 support multiple input voltage wiring configurations, enabling flexible testing of different electrical systems:

• 1P3W
• 3P3W
• 3P4W
• 3V3A

Users can select the appropriate configuration based on their measurement requirements, including the ability to calculate system efficiency.

The instruments support a rated input voltage up to 1000 V and an input current up to 20 A. The minimum current range is 0.5 A with a resolution of 0.1 mA.

• Power measurement resolution: 0.1 mW
• Crest factor: 3 (up to 6 at half range)
• Voltage/current/power accuracy: ±0.1% of reading ±0.05% of range

Available Measurement Parameters

Multiple measurement modes are available: AC+DC, AC, DC, and V-MEAN.

Up to 25 power-related parameters can be measured, including:

• Voltage: Vrms, Vac, Vdc, Vmn, V+pk, V-pk
• Current: Irms, Iac, Idc, I+pk, I-pk
• Frequency: VHz, IHz
• Power: P, P+pk, P-pk
• Apparent Power: VA
• Reactive Power: VAR
• Power Factor: PF
• Phase Angle: DEG
• Total Harmonic Distortion: THDV, THDI
• Crest Factor: CFV, CFI
• Maximum Current Ratio (MCR)
• Mathematical calculation functions

Display and Visualization

Thanks to the TFT LCD display, measurement results can be presented in both numerical and graphical formats.

In numerical display mode, two viewing options are available:

• General Mode: Four tabs (Page 1–4), each capable of displaying up to 10 parameters simultaneously (2 main measurements and 8 monitoring parameters).
• Multiple Mode: Simultaneous display of results from three modules, ideal for analyzing unbalanced three-phase systems.

In graphical mode, a simplified oscilloscope view displays voltage, current, and power waveforms. Harmonic measurements can also be shown using numerical values or bar chart representations.

Advanced Measurement Capabilities

The GPM-8320/8330 include several features for advanced measurement applications:

• VT ratio configuration for external potential transformers
• Compatibility with current transformers (CT)
• External sensor input terminals (EXT1 / EXT2)
• Customizable automatic range switching
• Internal memory capable of storing up to 10,000 data logs

Data Acquisition and Communication

For data acquisition and integration into automated test systems, the instruments provide several communication interfaces:

• RS-232C
• USB Device (Virtual COM)
• LAN
• Optional GPIB

The USB Host interface supports screen capture, internal data logging, and firmware updates.

An optional Digital I/O interface (DA12) can also be factory installed. This interface allows connection to external controllers such as PLC systems or data recorders, enabling automated measurement setups and long-term data recording applications.

GPM-8320/8330: Features and Capabilities

Wiring Selection

The GPM-8320/8330 models offer multiple input configurations and wiring modes (1P3W, 3P3W, 3P4W, 3V3A). Users can select the mode that best suits their specific requirements to measure parameters according to the wiring method, and even calculate system efficiency.

Versatile Display Modes

The GPM-8320/8330 provide two display modes—numerical and graphical—to maximize the value of your measurements.

• Numerical Mode: Two options are available: single and multiple. In single mode, four customizable tabs display up to 10 measurement parameters (2 primary and 8 secondary). In multiple mode, four tabs allow simultaneous observation of the same 8 parameters from three different modules. Parameters can be arranged and customized, and a simplified mode displays only the first four parameters.
• Graphical Mode: Features a basic oscilloscope function that shows waveforms for voltage, current, and power. The horizontal scale is adjustable (50 μs/div to 10 ms/div depending on data update rate), with three zoom levels. For harmonic measurements, results can be displayed in a bar chart by order, with full recording of voltage, current, power, distortion percentages, and phase angles.

Extensive Measurement Parameters

The GPM-8320/8330 measure a wide range of parameters, including voltage, current, frequency, active, apparent, and reactive power, power factor, crest factor, total harmonic distortion, and maximum current ratio. They also support time-integration measurements of power or current for the DUT. Automatic range switching ensures accurate integration results even when the DUT's power varies over time.

Advanced Measurement Assistance

• High-voltage and high-power measurements with voltage/power ratio correction for accurate results.
• High-current measurement with EXT1/EXT2 terminals for external sensors and voltage-output current transformers.
• Four panel configuration sets for storage/recall, with memory for up to 10,000 measurements.
• Front-panel USB support for screen capture, data storage, and firmware updates.

Flexible Range Switching

Automatic range switching for integration measurements allows users to calculate total power variations over the integration period. Customizable manual range selection is also available to optimize speed and efficiency during testing.

F. Convenient and Comprehensive Interface

The instruments provide multiple communication interfaces, including RS-232, USB, LAN, and optional GPIB, for remote control and data collection via software. The optional Digital I/O (DA12) interface offers three modes: external control, DA12 output, and custom output. These modes allow users to start, stop, trigger, or reset integration measurements, output up to 12 selected parameters to a data recorder, or define custom pin actions through commands.

Ordering Information

Standard Accessories

• Safety instruction sheet ×1
• Power cord ×1
• Test leads:
  • GPM-8320: GTL-209 ×2, GTL-212A ×2
  • GPM-8330: GTL-209 ×3, GTL-212A ×3
• GTL-214 DA12 cable (included only with GPM-DA12 option)

Optional Accessories

• GPM-DA12 – GPIB + DA12 interface (includes GTL-214 cable)
• GCP-300 – Current probe suitable for EXT2 external input connection
• GTL-209 – Test lead, banana to bare wire (~1000 mm)
• GTL-212A – Test lead, O-type to bare wire (~1000 mm)
• GTL-214 – DA12 cable (~1000 mm)
• GTL-232 – RS-232C cable, 9-pin female to 9-pin null modem (~2000 mm)
• GTL-246 – USB cable, type A-B (~1200 mm)
• GTL-258 – GPIB cable, 25-pin Micro-D connection (~1900 mm)
• GRA-452 – 19” rack mount kit (3U size)