[USB-045A] 2 Channel USB 4-20mA Current Monitor
Under Development
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Supports measurement of standard 4-20 mA
instrumentation signals via USB.
Each channel is independently isolated from the USB interface.
Overview
USB-045A is a converter capable of measuring two channels 4-20 mA current. It connects to a computer via USB, allowing measurement results to be displayed and logged. The USB interface and each channel are independently isolated. In addition, an A/D converter is provided for every two channels, enabling simultaneous measurement of two channels. Dedicated control commands are also provided, enabling 4-20 mA measurement from user applications.

* Second and subsequent images are CG models
Features
- 2 channel 4-20 mA measurement data acquisition via USB
- Measurement Range: 0-25 mA
- Measurement Accuracy: ≤ ±0.25% FS
- USB side and each channel are electrically isolated (2500 VDC)
- Easy control via virtual COM port with USB connection to a PC
- Enables 4-20 mA current output, auto-step, and auto-sweep operation via the included application
- Enables 4-20 mA output from user applications using dedicated control commands
- Controllable from embedded Linux devices
It operates as a device of the standard CDC-ACM class.
For Linux distributions with embedded CDC-ACM device drivers, you can use them without installing the drivers.
We do not support the use of Linux itself. - No external power supply is required
USB-045A is powered through a USB port (Bus-powered) - ESD and surge protection
- Pluggable the screw terminal
- Housing material: Plastic
- DIN rail, magnet, and screw mountable (Attachment is required)
- Includes a USB cable (1.8 m)
- Free from the 10 RoHS-restricted substances.
- MADE IN JAPAN
Specification
| Item | Description | Remarks |
|---|---|---|
| Model | USB-045A | |
| Input Power | 5 VDC / 350 mA max. Supplied via USB cable |
No external power supply required |
| HOST Interface | USB 2.0 compliant (Full-Speed supported) USB-B connector |
USB 1.1 compatible ESD protection |
| 4-20 mA Connector | 3-pin terminal block x 2 | Phoenix Contact Model: 1759020 |
| Measuring Range | 0 to 25 mA | |
| Number of Channels | 2 | |
| Resolution | 24-bit A/D Converter (ADC) | |
| Measurement Accuracy | ≤ ±0.25% FS | |
| Sampling Period | Minimum setting unit: 10 ms | Selectable by command |
| Shunt Resistor | 200Ω ±0.01% | |
| Isolation Method | Independent bus isolation | |
| Isolation Protection | 2500 VDC | Designed value |
| LSI | General-purpose microcontroller 4-20 mA ADC |
|
| LED | PWR: Power LED | |
| Control Method | Communication control via virtual COM port | |
| Operating Ambient Temperature | -20℃ to 60℃ (-4°F to 140°F) | No condensation permitted |
| Operating Ambient Humidity | 30% to 85% RH | No condensation permitted |
| Storage Ambient Temperature | -20℃ to 60℃ (-4°F to 140°F) | No condensation permitted |
| Storage Ambient Humidity | 30% to 85% RH | No condensation permitted |
| Weight | Approx. 90 g | Only main body |
| Dimensions | 67 x 67 x 28 mm (2.638" x 2.638" x 1.102") |
Without projections |
* There is a case to be changed to the parts of the compatibility.
* Power saving function (suspend, standby, sleep and others) is not supported
Application
This application runs on Windows and supports Windows 11 and Windows 10. By sending control commands to the device via USB, the application can output current from the device.
The application provides the following main functions:
- Current output using 4-20 mA current set values
- Current output using scaling settings
and more

USB-045 CV-Monitor download page.
Connector (PIN ASSIGNMENT)
| Pin No | Signal |
|---|---|
| 1 | NC |
| 2 | Current Terminal (−) |
| 3 | Current Terminal (+) |
Package Contents
- USB-045A
- USB cable 1.8 m
Documentation
Price and Optional Accessories
| Description | MODEL | Image | List Price (JPY) | Stock Status |
|---|---|---|---|---|
| 2 Channel USB 4-20mA Current Monitor |
USB-045A | ![]() |
||
| Attachment with clamping screw |
PEN-003 | ![]() |
||
| Attachment for 35mm DIN rail |
PEN-003-DIN | ![]() |
||
| Attachment with neodymium magnet |
PEN-003-MG | ![]() |
||
| Detachable 3P Terminal Connector 1757022 (Phoenix) (Additional purchase) |
TB-USB-3 | ![]() |


User's manual, Outline Drawing, etc





