What it is
Digital power meters for three-phase AC power measurement, with 2 input modules (GPM-8320) or 3 (GPM-8330), measuring from DC and 0.1 Hz to 100 kHz across 25 power parameters.
16-bit A/D converters sample at approximately 300 kHz, and results appear on a 5-inch TFT LCD with 5-digit readings. Basic voltage and current accuracy is ±(0.1% of reading + 0.05% of range) at 45 … 66 Hz.
- Two models: GPM-8320 (2 modules), GPM-8330 (3 modules)
- Measurement bandwidth: DC, 0.1 Hz … 100 kHz
- 16-bit A/D converters, approx. 300 kHz maximum conversion rate
- Voltage ranges: 15 V, 30 V, 60 V, 150 V, 300 V, 600 V, 1,000 V
- Current ranges (direct input): 0.5 A, 1 A, 2 A, 5 A, 10 A, 20 A
- External sensor inputs: EXT1 2.5 … 10 V; EXT2 50 mV … 2 V
- Basic accuracy: ±(0.1% of reading + 0.05% of range) at 45 … 66 Hz for voltage and current
- 25 measurement parameters, waveform display, integration, and harmonics analysis (50/60 Hz complies with IEC 61000-4-7)
- Wiring modes: 1P3W, 3P3W, 3P4W, 3V3A
- Interfaces: RS-232C, USB device and host, LAN; optional GPIB+DA12
What it is used for
Some of the use cases for the GPM-8320/8330 include:
- Three-phase AC power measurement
- Electrical and electronic product testing
- Efficiency calculation — across modules
- Unbalanced three-phase comparison — between modules
- Power consumption measurement — of electrical and electronic products, etc.
What does the GPM-8320/8330 do?
The GPM-8320 and GPM-8330 are digital power meters designed specifically for measuring power in three-phase AC power sources: the GPM-8320 provides 2 modules and the GPM-8330 provides 3. They have a testing bandwidth of DC and 0.1 Hz … 100 kHz, 16-bit A/D converters, and a sampling rate of 300 kHz.
The GPM-8320/8330 also feature waveform display capabilities (voltage/current/power), the integration measurement function, harmonics measurement and analysis of multiple orders (50/60 Hz measurement complies with IEC 61000-4-7 requirements), external sensor input terminals, and a variety of communications interfaces. These features help users achieve clear, convenient, and accurate power measurements, making them the most fully featured and cost-effective power meters in the same category.
The GPM-8320/8330 provide multiple input voltage configuration wiring modes (1P3W/3P3W/3P4W/3V3A). Users can choose the wiring mode according to their specific requirements to measure parameters for specific wiring methods, and even calculate efficiency. In addition, for a rated input voltage of 1,000 V and an input current of 20 A, they support a minimum current range of 0.5 A (resolution 0.1 mA), power measurement resolution of 0.1 mW, a crest factor of 3 (for half range, the CF can reach up to 6 or 6A), and voltage/current/power measurement accuracy of ±0.1% of reading ±0.05% of range. Users can select different measurement modes (AC+DC/AC/DC/V-MEAN) to provide up to 25 related parameters for power measurement.
These parameters include 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), crest factor (CFV/CFI), apparent power (VA), reactive power (VAR), power factor (PF), phase angle (DEG), total harmonic distortion (THDV/THDI), maximum current ratio (MCR), and the MATH calculation function. Therefore, they provide the best range and accuracy support for measuring the power consumption of electrical and electronic products.
Numerical display offers a general mode, with 4 tabs of 10 parameters each (2 main plus 8 monitoring measurements), and a multiple mode that displays the results of three modules simultaneously, for comparing differences between modules such as unbalanced three-phase.
Why engineers pick it
- Wide bandwidth from one instrument. Measurement covers DC and 0.1 Hz to 100 kHz, with 16-bit simultaneous conversion of voltage and current at approximately 300 kHz.
- Standards-compliant harmonics. Voltage, current, and power harmonics run from a 10 Hz to 1.2 kHz fundamental, and 50/60 Hz measurement complies with IEC 61000-4-7 at update rates above 0.5 s.
- Compare modules side by side. Multiple display mode shows three modules at once, which makes unbalanced three-phase differences and module-to-module efficiency visible on one screen.
- Beyond the direct input range. External current sensor inputs accept 2.5 … 10 V (EXT1) or 50 mV … 2 V (EXT2), so currents above the 20 A direct range can be measured through a shunt or clamp.
Which GPM model do I need?
| Model | Input modules | Interfaces |
| GPM-8320 | 2 | RS-232C / USB device & host / LAN |
| GPM-8320 (with GPM-DA12) | 2 | RS-232C / USB device & host / LAN and optional GPIB+DA12 |
| GPM-8330 | 3 | RS-232C / USB device & host / LAN |
| GPM-8330 (with GPM-DA12) | 3 | RS-232C / USB device & host / LAN and optional GPIB+DA12 |
The GPM-DA12 option is a 2-in-1 GPIB + DA12 interface (including cable GTL-214) and must be installed at the factory, so choose it with the instrument rather than adding it later.
What else does the GPM-8320/8330 do?
- Integration: manual, standard, or repetitive integration mode, with a timer settable from 0 to 9,999 hours 59 minutes 59 seconds and ±0.02% timer accuracy.
- Peak measurement: captures the maximum and minimum of voltage, current, and power from the sampled instantaneous values.
- Line and frequency filters: each selectable on or off, with a 500 Hz cutoff.
- Zero-level compensation: removes the internal offset of the measuring unit after a range change.
- D/A output and remote control (option): 12 channels of ±5 V full-scale analog output at 16-bit resolution, plus EXT HOLD, TRIG, START, STOP, and RESET inputs with an INTEG BUSY output.
When is the GPM-8320/8330 the wrong choice?
- Input above 1,000 V or 20 A direct. Continuous maximum input is 1.5 kV peak or 1 kVrms, whichever is less, and 100 A peak or 30 Arms on the direct current input. Higher currents need an external sensor.
- Harmonics above 1.2 kHz fundamental. Harmonic measurement covers a 10 Hz to 1.2 kHz fundamental, with the upper analysis order dropping as the fundamental rises.
- Very low signal levels. Apparent and reactive power read zero, and power factor and phase angle show “--”, when voltage or current falls below 0.5% of the rated range (1% at crest factor 6).
- Hot or humid environments. Operating range is 32 … 104 °F (0 … 40 °C), with humidity below 70% RH above 86 °F (30 °C).
Standard Accessories
- Safety instruction sheet × 1, power cord × 1
- Test lead GTL-209 × 2, test lead GTL-212A × 2 — GPM-8320
- Test lead GTL-209 × 3, test lead GTL-212A × 3 — GPM-8330
- CD × 1 (complete user manual and USB driver), GPM-002 terminal cover
- DA12 cable GTL-214 (available for GPM-8320/8330 with GPM-DA12 only)
