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Single-Phase Digital Meters from China Suppliers | Quality Factory Measurement Solutions for AC/DC Systems
โก Product Overview
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1. Digital AC Voltmeter
1.1 Measuring Range & Configuration
The single-phase digital AC voltmeter offers two flexible measurement modes to accommodate low-voltage and ultra-high-voltage (UHV) single-phase AC systems:
Direct Measurement Range
0 ~ 600 V AC
Supports direct connection to standard single-phase AC systems (e.g., 120 V, 220 V, 230 V, 240 V, 400 V, 600 V) without external signal conditioning equipment. Ideal for on-site monitoring of lighting circuits, small appliance power supplies, and light industrial load systems.
Extended Measurement Range โ With PT Required
0 ~ 9999 kV AC
For high-voltage (HV) and UHV single-phase AC system monitoring (e.g., transmission lines, substations), the voltmeter is paired with a voltage transformer (PT) calibrated to a standard secondary output of 100 V AC. The primary voltage range (0 ~ 9999 kV) is determined by the PT ratio (e.g., 110 kV/100 V, 500 kV/100 V). The PT provides galvanic isolation between the high-voltage primary circuit and the voltmeter, ensuring operator safety and protecting the meter from overload damage.
1.2 Core Measurement Features
- True RMS measurement algorithm, ensuring accurate voltage readings even with distorted waveforms caused by non-linear loads (e.g., switching power supplies, LED lighting).
- High-visibility digital display with clear unit indication (V/kV) for quick on-site data verification.
- Overvoltage indication function to alert users of abnormal voltage conditions in the monitored system.
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2. Digital DC Voltmeter
2.1 Measuring Range
The single-phase digital DC voltmeter is engineered for direct measurement of DC voltage systems, with no need for external auxiliary devices for the specified range:
Direct Measurement Range
0 ~ 600 V DC
Covers common single-phase DC applications, including battery banks, DC motor drives, solar PV system outputs, and DC power supply units. The direct connection design simplifies installation and eliminates signal loss associated with auxiliary transformers.
2.2 Core Measurement Features
- High-precision linear measurement with minimal drift, suitable for both steady-state and fluctuating DC voltage monitoring.
- Polarity reversal protection to prevent meter damage when connected with incorrect terminal polarity.
- Compact DIN-rail or panel-mount design for seamless integration into control panels and electrical enclosures.
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3. Digital AC Ammeter
3.1 Measuring Range & Configuration
The single-phase digital AC ammeter supports two measurement configurations to meet low-current and high-current single-phase AC system monitoring needs:
Direct Measurement Range
0 ~ 10 A AC
Ideal for direct connection to low-current single-phase AC circuits (e.g., lighting systems, small fans, control circuits), eliminating the need for external current transformers (CTs) and reducing installation complexity.
Extended Measurement Range โ With CT Required
0 ~ 9999 A AC
For high-current single-phase AC system monitoring (e.g., large industrial motors, welding equipment, distribution feeder currents), the ammeter is integrated with a current transformer (CT) rated for a standard secondary output of 5 A AC. The primary current range (0 ~ 9999 A) is defined by the CT ratio (e.g., 100 A/5 A, 500 A/5 A, 1000 A/5 A). The CT isolates the ammeter from high primary currents, preventing overload damage and ensuring measurement precision.
3.2 Core Measurement Features
- Accurate RMS current measurement, with support for configurable display scaling to match CT ratios for direct primary current indication.
- Overcurrent alarm function to notify users of excessive current draw, helping to prevent equipment overheating and damage.
- Compatibility with standard CT models, enabling easy system expansion and retrofitting.
๐ Technical Parameters
๐ Scroll horizontally to view full table
| Function & Shape / Model | Measure & Display | Shape Code (Figure Inside โก) | Selected Additional Functions | ||||||||
| Current | Voltage | Frequency | โจ | โง | 7 | 5 | โฃ | Communication Interface: RS485 | 2-Channels Switch Output | 1-Channel Analog Output | |
| 96ร96 | 80ร80 | 72ร72 | 96ร48 | 48ร48 | |||||||
| SFS-โกK1-I | โ | โ | โ | ||||||||
| SFS-โกK1-U | โ | โ | โ | โ | |||||||
| SFS-โกK1-F | โ | โ | โ | โ | |||||||
| SFN-โกK1-I | โ | โ | โ | โ | โ | โ | |||||
| SFN-โกK1-U | โ | โ | โ | โ | โ | โ | |||||
| SFN-โกK1-F | โ | โ | โ | โ | โ | โ | |||||
| SFN-โกK1-I+RS | โ | โ | โ | โ | โ | + | |||||
| SFN-โกK1-U+RS | โ | โ | โ | โ | โ | + | |||||
| SFN-โกK1-F+RS | โ | โ | โ | โ | โ | + | |||||
| SFN-โกK1-I+2DO | โ | โ | โ | โ | โ | + | |||||
| SFN-โกK1-U+2DO | โ | โ | โ | โ | โ | + | |||||
| SFN-โกK1-F+2DO | โ | โ | โ | โ | โ | + | |||||
| SFN-โกK1-I+1AO | โ | โ | โ | โ | โ | + | |||||
| SFN-โกK1-U+1AO | โ | โ | โ | โ | โ | + | |||||
| SFN-โกK1-F+1AO | โ | โ | โ | โ | โ | + | |||||
โ Frequently Asked Questions
Q
What is the difference between the SFS and SFN series digital panel meters?
The SFS series supports basic measurement functions with limited size options (96ร96 and 72ร72), making it suitable for standard applications. The SFN series offers a wider range of panel sizes (96ร96, 80ร80, 72ร72, 96ร48, 48ร48) and supports optional add-on functions such as RS485 communication, 2-channel switch output (2DO), and 1-channel analog output (1AO), providing greater flexibility for advanced monitoring and automation systems.
Q
Do I need a voltage transformer (PT) to measure high-voltage AC systems above 600 V?
Yes. For AC voltages exceeding 600 V โ such as transmission lines or substation feeders โ a voltage transformer (PT) with a standard secondary output of 100 V AC is required. The PT steps down the primary high voltage to a safe level for the meter input while providing galvanic isolation to protect both the operator and the instrument. The displayed reading is automatically scaled according to the configured PT ratio.
Q
Can the digital AC ammeter measure currents higher than 10 A without a current transformer (CT)?
No. The direct measurement range of the digital AC ammeter is limited to 0โ10 A AC. For currents exceeding 10 A โ up to 9999 A โ a current transformer (CT) with a standard secondary output of 5 A AC must be used. The CT ratio (e.g., 100 A/5 A, 1000 A/5 A) determines the measurable primary current range, and the meter display can be configured to show the actual primary current value directly.
Q
Is the digital DC voltmeter suitable for solar PV and battery storage applications?
Yes. The digital DC voltmeter with a direct measurement range of 0โ600 V DC is well-suited for solar PV system output monitoring, battery bank voltage measurement, and DC motor drive supervision. Its polarity reversal protection feature prevents damage from incorrect wiring, and its high-precision linear measurement ensures reliable readings under both steady-state and fluctuating DC conditions.
Q
What communication interface is available for remote monitoring and data logging?
The SFN series meters support an optional RS485 communication interface (Modbus RTU protocol is standard for this product type). Models with the "+RS" suffix in the model code include this function. RS485 enables integration with SCADA systems, PLCs, and building management systems (BMS) for real-time remote monitoring, data logging, and alarm management over long communication distances.
Q
What are the switch output (2DO) and analog output (1AO) options used for?
The 2-channel switch output (2DO) option provides relay or transistor outputs that can be configured as alarm contacts โ for example, triggering an alert when voltage or current exceeds a set threshold. This is useful for automatic protection or annunciator systems. The 1-channel analog output (1AO) converts the measured value into a proportional analog signal (typically 4โ20 mA or 0โ10 V), enabling integration with analog input controllers, data acquisition systems, or remote display panels.