Isolated Analog Signal Converter 75mV ...
The AC-75MV-420 is an industrial precision millivolt signal conditioner designed to convert the 0–75mV DC drop across external current shunts into an industry-standard, isolated 4–20mA active current loop signal. Built with a pure linear analog isolation amplifier without PWM conversion or digital reconstruction, it achieves an ultra-fast response time (< 1 ms) and exceptional signal fidelity (< ±0.1% output ripple). With a robust 4.25 kV RMS galvanic isolation barrier between high-current DC shunts and sensitive control circuitry, it eliminates hazardous ground loops and common-mode transients, enabling safe, highly accurate DC current measurement for battery energy storage, electroplating, solar PV arrays, and DC motor drives.
Key Features
- 0–75mV DC shunt input to 4–20mA isolated current loop conversion
- 4.25 kV RMS galvanic isolation between shunt input and output
- 1.5 kV RMS isolation between input and auxiliary power
- Ultra-fast response time (< 1 ms) for rapid overcurrent detection
- Low output ripple noise (< ±0.1%) with ±0.2% full-scale accuracy
- Pure analog linear amplifier topology with zero digital sampling artifacts
- Front-panel multi-turn Zero and Span calibration potentiometers
- 24V DC auxiliary power supply (18V to 30V DC operating range)
- Compact 22 mm DIN rail and wall mountable enclosure
- Dimensions: 100 mm × 76 mm × 22 mm
Ordering Information
| Product Code | Description |
|---|---|
| AC-75mV-420 | Isolated Shunt Converter 0–75mV DC to 4–20mA (24V DC, 4.25kV Isolation) |
| AC-B75mV-420 | Isolated Bipolar Shunt Converter ±75mV DC to 4–20mA |
| AC-420-420 | Signal Isolator 4–20mA to 4–20mA Current Loop Isolator |
| SPD-20MA | 4–20mA Surge Protection Device |
| USS20M24V-D | Current Source Simulator 0/4 to 20mA with Digital Display |
| SPD-24V-DC | Surge Protection Device 24V DC SPD |
Applications
- DC Current Shunt Telemetry: Directly converts millivolt signals across high-amperage shunts into 4–20mA for PLCs.
- Battery Energy Storage Systems (BESS): Measuring battery charge/discharge current profiles with total galvanic isolation.
- Electroplating & Chemical Rectifiers: Safe current feedback from high-current low-voltage electroplating DC buses.
- Solar Photovoltaic Inverters & DC Combiners: Centralized current monitoring across parallel solar panel strings.
- DC Motor Drive Current Sensing: Rapid current feedback for DC motor torque and load supervision.
Specifications
| Parameter | Value |
|---|---|
| Mounting Type | 35 mm DIN Rail & Wall Mounting |
| Dimensions | 100 mm x 76 mm x 22 mm (L x H x W) |
| Weight | 100 g |
| Enclosure Material | Industrial Grade ABS |
| Operating Temperature | 0 °C to +50 °C (Industrial: -10 °C to +60 °C) |
| Storage Temperature | -40 °C to +85 °C |
| Relative Humidity | 5% to 95% RH (non-condensing) |
Electrical Specifications
| Parameter | Specification |
|---|---|
| Power Supply Voltage | 24V DC \(\pm 25\%\) (18V to 30V DC) |
| Operating Current | 100 mA @ 24V DC |
| Input Signal Range | 0.0 mV to 75.0 mV DC (Current Shunt Drop) |
| Input Impedance | \(> 100\,\text{k}\Omega\) |
| Output Signal Range | 4.00 mA to 20.00 mA (Active Current Loop, Load \(\le 500\,\Omega\)) |
| Conversion Accuracy | \(\pm 0.2\%\) of Full Scale @ 25 °C (max \(\pm 0.5\%\)) |
| Output Ripple Noise | \(< \pm 0.1\%\) of Full Scale |
| Response Time | \(< 1\text{ ms}\) (< 1 milliSec) |
| Temperature Drift | \(< 100\text{ ppm} / \text{°C}\) |
| Status Indication | Power LED ON (PWR) |
| Field Calibration | Front-panel multi-turn Zero and Span trimpots |
Isolation & Protection Specifications
| Parameter | Value | Standard / Notes |
|---|---|---|
| Galvanic Isolation (Input to Output) | 4,250 V RMS (4.25 kV) | Optical & magnetic isolation barrier (1 min) |
| Galvanic Isolation (Input to Aux. Power) | 1,500 V RMS (1.5 kV) | Continuous dielectric isolation |
| Output to Aux. Supply | Shared Common Ground | Non-isolated reference ground |
| Reverse Polarity Protection | Integrated | Protects internal circuitry against reverse DC supply wiring |
| Transient Clamping | 600W TVS | Surge and spike suppression across all ports |
Functional Isolation Architecture & Dynamic Response
The pure linear analog architecture provides true continuous signal isolation without quantization stepping or switching ripples.
Oscilloscope Dynamic Waveform Verification
Oscilloscope measurement verifying that the isolated output signal reproduces the input waveform with sub-millisecond response latency (< 1 ms) and clean signal fidelity:
Mechanical Dimensions
Terminal Details & Wiring
Connection Pinouts
| Terminal Block | Pin | Label | Signal | Description |
|---|---|---|---|---|
| Input Terminals | 18 | 18 + | Shunt (+) | 0–75mV DC Shunt Positive Lead (+) |
| (Bottom Block) | A2 | A2 - | Shunt (-) | 0–75mV DC Shunt Negative Lead (-) |
| – | NC | Unused | Reserved / Not Connected | |
| – | NC | Unused | Reserved / Not Connected | |
| Output Terminals | 15 | 15 OP+ | Output (+) | Active 4–20mA Analog Output (+) |
| (Top Block) | 26 | 26 OP- | Output (-) | Analog Output Ground Return (-) |
| Power Terminals | A1 | A1 V+ | +24V DC | Auxiliary Power Supply Input (+24V DC) |
| (Top Block) | 25 | 25 GND | Power 0V | Auxiliary Power Supply Ground Return |
Available Variants & Configurations
The Veawe Precision Analog Isolator family is available in standardized and custom input/output configurations:
| Signal Converter Input | Output | High Voltage Input | Output | Transducer Input | Output |
|---|---|---|---|---|---|
| 0–20 mA | 0–20mA, 4–20mA, 0–10V, ±10V | 30V DC | 0–20mA, 4–20mA, 0–10V | Pt100 | 0–20mA, 4–20mA, 0–10V |
| 4–20 mA | 0–20mA, 4–20mA, 0–10V, ±10V | 70V DC | 0–20mA, 4–20mA, 0–10V | Pt1000 | 0–20mA, 4–20mA, 0–10V |
| 0–10 V DC | 0–20mA, 4–20mA, 0–10V, ±10V | 100V DC | 0–20mA, 4–20mA, 0–10V | K type | 0–20mA, 4–20mA, 0–10V |
| 0–5 V DC | 0–20mA, 4–20mA, 0–10V, ±10V | 150V DC | 0–20mA, 4–20mA, 0–10V | J type | 0–20mA, 4–20mA, 0–10V |
| 75 mV DC | 0–20mA, 4–20mA, 0–10V, ±10V | 300V / ±300V DC | 0–20mA, 4–20mA, 0–10V | Resistance | 0–20mA, 4–20mA, 0–10V |
| ±75 mV DC | 0–20mA, 4–20mA, 0–10V, ±10V | 350V DC | 0–20mA, 4–20mA, 0–10V | — | — |
| — | — | 100V AC | 0–20mA, 4–20mA, 0–10V | — | — |
| — | — | 5A AC (CT) | 0–20mA, 4–20mA, 0–10V | — | — |
LED Indications and Diagnostics
| LED | Color | Status | Description |
|---|---|---|---|
| PWR | Green | ON | Auxiliary 24V DC operating power connected and regulated |
Revision History
| Revision | Date | Description of Change |
|---|---|---|
| Rev 1.0 | 2026-09-09 | Initial datasheet release |
Get the latest version of this datasheet : click here..
Support
Website: www.veawe.io
Email: info@veawe.io