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The NI PXIe-4138/4139 is a PXI Express (PXIe) Precision System Source Measure Unit (SMU) designed for high-accuracy sourcing and measurement applications. This device is capable of handling a wide range of voltage and current, specifically ±60 V and ±3 A (DC), with pulsed current capabilities up to ±10 A. It is intended for use within a PXI Express chassis, integrating seamlessly into automated test and measurement systems.
The PXIe-4138/4139 functions as a versatile SMU, combining the capabilities of a precision voltage source, a precision current source, a voltage meter, and a current meter into a single PXI Express module. This integration allows for precise control over sourcing and measuring electrical parameters, making it suitable for characterizing a wide array of electronic components and devices. The module is driven by NI-DCPower driver software, which provides the necessary interface for programming and controlling the device. Users can generate signals interactively using InstrumentStudio, a software-based soft front panel application, or program the device using the NI-DCPower instrument driver within supported application development environments (ADEs) such as LabVIEW, LabWindows/CVI, LabVIEW NXG, or C/C++.
The device offers multiple output channels, including Output LO, Sense LO, Guard, Output HI, Sense HI, and Chassis Ground, which are accessible via an output connector assembly. These connections facilitate various measurement configurations, including 4-wire (Kelvin) sensing, which helps to minimize the effects of lead resistance on measurements, ensuring higher accuracy. The Guard connection is particularly useful for reducing leakage currents and improving measurement integrity in sensitive applications.
The PXIe-4138/4139 includes LED indicators on its front panel to provide immediate status feedback. The Access Status LED indicates the power state and whether the device is being accessed. A green light signifies that the device is powered, while an amber light indicates that it is being accessed. If the LED is off, the device is not powered. The Active Status LED provides information about the output channel's operational state. A green light means the channel is operating in a programmed state, while a red light indicates a disabled channel due to an error, such as an overcurrent condition. If this LED is off, the channel is not operating in a programmed state.
To begin using the PXIe-4138/4139, users must first install the necessary software, including an ADE (e.g., LabVIEW) and the NI-DCPower driver software. The NI Package Manager facilitates the installation process. Once the software is installed, the module can be physically installed into a compatible PXI Express chassis. The PXIe-4138/4139 can be placed in PXI Express peripheral slots, PXI Express hybrid peripheral slots, or PXI Express system timing slots. Proper installation involves ensuring the chassis is grounded, powering off the chassis, inspecting slot pins for damage, and carefully sliding the module into the slot until fully inserted. The ejector handle is then used to latch the module, and front-panel mounting screws secure it to the chassis, which also improves signal quality and electromagnetic performance. After installation, the output connector assembly is connected to the device.
Configuration of the PXIe-4138/4139 is performed using Measurement & Automation Explorer (MAX). MAX automatically detects and lists installed NI hardware, allowing users to verify the module's presence, record its identifier for programming, and perform a self-test. If the module does not appear in MAX, troubleshooting steps include refreshing the list, restarting the system, and checking the Device Manager for any error conditions.
A critical usage feature is self-calibration. While the PXIe-4138/4139 is externally calibrated at the factory, self-calibration is recommended in several scenarios to adjust for environmental variations and maintain measurement accuracy. This process involves allowing the module to warm up for 30 minutes after the chassis is powered on and the operating system has loaded, then initiating the self-calibration through MAX or by calling specific NI-DCPower functions. Self-calibration should be performed after initial installation, after any other module in the same chassis is installed, uninstalled, or moved, when the ambient temperature has drifted more than 5 °C from the last self-calibration temperature, and within 24 hours of the previous self-calibration.
Programming the PXIe-4138/4139 is flexible, supporting interactive control via InstrumentStudio for monitoring, controlling, and recording measurements, as well as programmatic control through the NI-DCPower instrument driver in various ADEs. InstrumentStudio offers a soft front panel interface that can be launched from the Windows start menu or directly from MAX. The NI-DCPower API provides functions for configuring and operating the module hardware and performing basic acquisition and measurement tasks, with examples available in the respective ADEs.
The manual emphasizes several maintenance-related practices to ensure the longevity and proper functioning of the PXIe-4138/4139. These include precautions against electrostatic discharge (ESD) during handling, such as grounding oneself before touching the module and storing it in its antistatic package when not in use. Users are explicitly warned not to touch exposed pins of connectors and not to install a module that appears damaged.
Environmental considerations are also highlighted as a maintenance aspect. The device is designed for indoor applications and has specific operating and storage temperature and humidity ranges. Adhering to these environmental specifications helps prevent damage and ensures reliable performance. The maximum altitude for operation is 2,000 m (800 mbar) at 25 °C ambient temperature, and the pollution degree is specified as 2.
Troubleshooting guidance is provided for common issues, such as the module not appearing in MAX or failing a self-test. For instance, if the ACCESS LED is off when the chassis is on, users are advised to disconnect external signals, power off the chassis, inspect the module for damage, try installing it in a different slot, and then power on the chassis and verify its appearance in MAX. If a self-test fails, restarting the system, performing self-calibration, and then re-running the self-test are recommended steps. If issues persist after these procedures, users are directed to contact NI technical support or visit ni.com/support.
The manual also points to NI services for ongoing support, including documentation, downloads, troubleshooting guides, tutorials, and examples. Calibration options, repair, and replacement services are available through ni.com/services. Product registration is encouraged to facilitate technical support and ensure users receive important updates.
General| Type | Source Measure Unit (SMU) |
|---|---|
| Channels | 1 |
| Maximum Current | 1 A |
| Interface | PXI Express |
| Operating Temperature Range | 0 °C to 55 °C |
| Storage Temperature Range | -20 °C to 70 °C |
| Relative Humidity | 10% to 90% |
