PXI-4022 6-Wire Guard and Current Amplifier Module
Земля NI PXI-4022 is a precision guard and current amplifier module designed to extend the measurement capabilities of compatible National Instruments PXI digital multimeters. It supports guarded six-wire resistance measurements and sensitive current measurements in automated test, component characterization and cable-test systems.
The PXI-4022 combines a high-speed precision voltage amplifier with three current ranges: 1 mA, 10 µA and 100 nA. When paired with a compatible NI digital multimeter, it helps engineers measure high resistance, very low current and resistors embedded in complex circuits where conventional two-wire or four-wire techniques may produce misleading results.
Key Features of the PXI-4022
- Guard and current amplifier for compatible PXI digital multimeters
- Supports guarded six-wire resistance measurements
- 1 mA, 10 µA and 100 nA current ranges
- High-speed, high-precision voltage-amplifier mode
- Greater than 10 GΩ amplifier input impedance
- Less than 5 pA amplifier input bias current
- 1 MHz minimum amplifier bandwidth
- 40 V/µs minimum slew rate
- ±12 V maximum amplifier output range
- ±15 mA maximum output-drive current
- Low burden voltage for sensitive current measurements
- Low-leakage and low-thermal signal connections
- Overvoltage-protected guard terminals
- Measurement Category II safety rating up to 250 V
- Software control through the NI-DMM driver
- Standard 3U PXI module format
PXI-4022 Technical Specifications
| Product Model | ПХИ-4022 |
|---|---|
| Part Number | 779614-01 |
| Product Type | PXI guard and current amplifier module |
| Primary Functions | Six-wire resistance measurement, guarding and low-current amplification |
| Current Ranges | 1 mA, 10 µA and 100 nA |
| Current Measurement Architecture | Feedback ammeter |
| 100 nA Range Burden Voltage | Less than 20 µV |
| Amplifier Input Impedance | Greater than 10 GΩ |
| Amplifier Input Bias Current | Less than 5 pA |
| Amplifier Output Voltage | ±12 V maximum |
| Amplifier Output Drive | ±15 mA maximum |
| Amplifier Bandwidth | 1 MHz minimum |
| Slew Rate | 40 V/µs minimum |
| Resistance Measurement Method | Guarded six-wire measurement with compatible DMM |
| Terminal Construction | Low-EMF, low-leakage, gold-plated solid-copper terminals |
| Safety Rating | Measurement Category II, up to 250 V signal circuits |
| Maximum Transient Overvoltage | 2,500 V |
| Software Driver | NI-DMM |
| Шинный интерфейс | PXI |
| Module Format | 3U, one-slot PXI module |
| Approximate Dimensions | 21.6 × 13.0 × 2.0 cm |
| Approximate Weight | 275 g |
PXI-4022 Part Number and Connectivity Accessories
| Item | Part Number | Описание |
|---|---|---|
| ПХИ-4022 | 779614-01 | Six-wire guard and current amplifier module for compatible PXI DMMs |
| Low-Leakage, Low-Thermal Cable Set | 779410-01 | Specialized cable set for low-current and precision resistance measurements |
| Low-Leakage, Low-Thermal Connectivity Set | 779499-01 | Connectivity accessories for guarded low-level measurement systems |
The electrical performance of a PXI-4022 installation depends strongly on its external cabling and fixture design. Verify the required cable length, terminal arrangement, insulation resistance, connector condition and compatibility with the selected DMM before ordering.
Guard and Current Amplifier Architecture
The PXI-4022 is not a standalone digitizer or complete digital multimeter. It conditions the measured signal and works with a compatible NI PXI DMM that digitizes the amplifier output and calculates the measurement result.
Its two principal operating functions are a precision voltage-amplifier mode and a feedback-current-amplifier mode. Software configures the required mode and range through the NI-DMM driver.
Guarded Six-Wire Resistance Measurements
Conventional four-wire resistance measurement compensates for lead resistance but may still include unwanted current flowing through parallel resistance paths. This is particularly problematic when measuring an individual resistor installed on a populated printed circuit board.
The PXI-4022 adds guard connections to the force and sense arrangement. A properly connected guard drives selected surrounding nodes to nearly the same potential as the measurement node, reducing leakage through parallel paths. This creates a six-wire guarded measurement architecture.
Six-wire measurements are useful for in-circuit resistance testing, cable insulation analysis and other applications where adjacent conductors or components would otherwise affect the result.
Low-Current Measurements
The PXI-4022 provides 1 mA, 10 µA and 100 nA current ranges. These ranges allow the module to convert a small input current into a voltage that a compatible PXI digital multimeter can measure accurately.
The most sensitive 100 nA range is suitable for leakage-current analysis, insulation testing and component characterization. Measurement resolution ultimately depends on the selected DMM, integration time, noise environment, cabling and test-fixture leakage.
Low-Burden Feedback Ammeter
Current meters introduce a voltage into the measured circuit known as burden voltage. Excessive burden voltage can change the operating point of a sensitive device and create a significant measurement error.
The PXI-4022 uses a feedback-ammeter architecture and provides less than 20 µV burden voltage on its 100 nA range. This low burden voltage helps minimize disturbance to high-impedance and low-current circuits.
High-Precision Voltage Amplifier
In amplifier mode, the PXI-4022 conditions small voltage signals before they are acquired by the associated digital multimeter. Its input impedance exceeds 10 GΩ, while the specified input bias current is less than 5 pA.
These characteristics reduce loading on high-impedance signal sources. They are especially important when measuring sensors, resistance networks and electronic components that cannot supply significant current.
1 MHz Amplifier Bandwidth
The voltage amplifier provides at least 1 MHz of bandwidth. This permits faster response than measurement arrangements intended only for slowly changing DC signals.
Actual system bandwidth depends on the selected gain, DMM configuration, source impedance, cable capacitance, fixture layout and connected device. High-impedance sources may require additional settling time because cable and fixture capacitance must charge before the reading stabilizes.
40 V/µs Slew Rate
A minimum slew rate of 40 V/µs allows the amplifier output to respond rapidly to changes in the input signal. This supports automated applications that must switch between test points or acquire a sequence of conditioned measurements.
Measurement speed should still be selected according to the required accuracy. Low-current and high-resistance readings commonly require longer settling and integration times than ordinary voltage measurements.
Guard Output Capability
The guard amplifier can produce an output within a maximum ±12 V range and drive up to ±15 mA. These limits must not be exceeded by the connected guard network or fixture.
The guard is an actively driven conductor rather than an ordinary ground or shield. It must be wired according to the intended measurement configuration. Connecting it incorrectly can create unstable readings, overload the amplifier or energize fixture conductors unexpectedly.
Low-Leakage Signal Connections
The PXI-4022 uses low-EMF, low-leakage terminals with gold-plated solid-copper conductors. These materials help reduce thermoelectric voltage and leakage effects that can become significant during nanoampere, picoampere and high-resistance measurements.
For best performance, connectors should remain clean and dry. Fingerprints, flux residue, dust and moisture can form leakage paths large enough to influence sensitive readings.
Overvoltage Protection
Overvoltage protection is provided for the Guard Out, Guard In+ and Guard In− terminals. This protection helps the module withstand accidental voltage exposure within the limits stated in the official specifications.
Protection circuitry does not make every wiring error safe. Test fixtures should include suitable fusing, current limiting and physical separation whenever they contain high-energy or hazardous-voltage circuits.
Measurement Category II Rating
The PXI-4022 is rated for Measurement Category II signal voltages up to 250 V and can withstand a 2,500 V transient overvoltage under its specified safety conditions.
Users must evaluate the rating of the complete measurement path, including the DMM, PXI-4022, probes, cables, connectors and fixture. The component with the lowest voltage or measurement-category rating determines the system limit.
Compatible Digital Multimeters
The PXI-4022 was designed as an accessory for compatible NI PXI digital multimeters. Common system configurations pair it with high-performance instruments such as the PXI-4071 digital multimeter или PXI-4072 digital multimeter and LCR meter.
Compatibility can depend on the installed NI-DMM version, operating system and measurement mode. Confirm the complete hardware and software combination when adding a PXI-4022 to an existing system.
NI-DMM Software Support
The module is configured through the NI-DMM instrument driver. NI-DMM includes functions for selecting the PXI-4022 operating mode, configuring current ranges and coordinating measurements with the associated digital multimeter.
Applications can be developed in LabVIEW, LabWindows/CVI and supported text-based programming environments. NI Measurement & Automation Explorer can be used to identify the installed hardware and verify driver communication.
Typical PXI-4022 Applications
- Guarded six-wire resistance measurement
- In-circuit resistor testing
- Printed circuit board resistance analysis
- Cable and connector leakage testing
- Insulation-resistance characterization
- Nanoampere and picoampere measurement systems
- Semiconductor leakage-current testing
- Sensor and high-impedance source measurements
- Automated component characterization
- Research and laboratory measurements
- Production test systems
- Electrochemical and corrosion-current measurements
In-Circuit Resistance Testing
A resistor mounted on a circuit board may be connected in parallel with other resistors, semiconductor junctions or leakage paths. A normal resistance measurement can therefore report the resistance of the entire network rather than the intended component.
With the correct six-wire connection, the PXI-4022 guard can reduce current through unwanted parallel paths. This allows more selective measurement without removing the component from the board in suitable circuit configurations.
Leakage and Insulation Testing
The sensitive current ranges make the PXI-4022 useful for evaluating leakage through cables, connectors, insulating materials and electronic assemblies. It can help identify contamination, damaged insulation and manufacturing defects that produce small unintended currents.
Low-current fixtures should use high-quality insulating materials and guarded conductors. Humidity, surface contamination and cable movement can all cause measurement changes that are unrelated to the device under test.
PXI-4022 Troubleshooting
The PXI-4022 is not detected
Confirm that the module is fully inserted into a compatible PXI slot. Check chassis power, controller communication and the installed NI-DMM version. Open NI Measurement & Automation Explorer and rescan the PXI system.
The current reading is unstable
Inspect the cable and fixture for contamination, moisture and poor insulation. Increase settling or integration time, eliminate nearby interference sources and verify that the guard is connected to the intended circuit node.
The reading changes when the cable moves
Cable motion can generate triboelectric current and change parasitic capacitance. Use low-noise cables intended for low-current measurements, secure them mechanically and avoid movement while readings are acquired.
The resistance result is lower than expected
Check for parallel circuit paths that have not been guarded effectively. Verify all force, sense and guard connections and confirm that the selected guard point does not interfere with the intended measurement.
The amplifier output is saturated
Confirm that the input signal, selected range and gain keep the output within the ±12 V limit. Inspect the test fixture for unexpected current, excessive guard loading or incorrect terminal connections.
Measurements drift after power-up
Allow the PXI chassis, DMM, PXI-4022 and test fixture to reach a stable operating temperature. Reduce air movement and temperature gradients around low-thermal connections.
The lowest current range produces excessive noise
Use shielding, guarding, clean insulation and an appropriate integration time. Disconnect unnecessary equipment, avoid ground loops and keep high-voltage switching or digital lines away from sensitive input wiring.
PXI-4022 Comparison with Related Measurement Modules
| Модель | Primary Function | Best Suited For |
|---|---|---|
| ПХИ-4022 | Guard and current amplification | Six-wire resistance and very-low-current measurements with a compatible DMM |
| PXI-4065 | 6½-digit digital multimeter | General-purpose voltage, current and resistance measurements |
| PXI-4070 | 6½-digit FlexDMM | High-speed precision measurements in legacy PXI systems |
| PXI-4071 | 7½-digit FlexDMM | High-resolution precision DC measurements |
| PXI-4072 | 6½-digit DMM and LCR meter | Precision DMM measurements plus inductance and capacitance testing |
PXI-4022 vs PXI-4071
The PXI-4022 and PXI-4071 perform complementary functions. The PXI-4071 is the digital multimeter that digitizes and calculates measurements, while the PXI-4022 provides guarding and sensitive current amplification.
Choose a PXI-4071 alone for conventional precision voltage, current and resistance measurements. Add the PXI-4022 when the application requires guarded six-wire resistance or current ranges extending into very-low-current measurements.
PXI-4022 vs a Standalone Picoammeter
A standalone picoammeter combines signal conditioning, digitization and display in one instrument. The PXI-4022 instead integrates low-current measurement capability into a modular PXI system by working with a compatible DMM.
The PXI approach is useful when low-current measurements must be synchronized with switching, stimulus generation and other automated instruments. A standalone instrument may be more convenient for an isolated bench measurement.
Recommended Related Products
- PXI-4071 7½-Digit FlexDMM
- PXI-4072 6½-Digit DMM and LCR Meter
- PXI-4065 6½-Digit Digital Multimeter
- PXIe-4080 7½-Digit PXI Express Digital Multimeter
- PXI-2535 High-Speed Matrix Switch Module
- View More NI PXI and PXI Express Modules
Selecting a PXI-4022 Measurement System
Choose the PXI-4022 when an application requires guarded six-wire resistance measurements, low-burden current amplification or improved sensitivity for high-impedance devices. Select the associated digital multimeter according to the required resolution, measurement speed and supported NI-DMM environment.
Before purchasing, verify DMM compatibility, PXI chassis availability, operating-system support and cable requirements. Because the PXI-4022 is a legacy product, confirm whether the available unit is new surplus, used or refurbished and whether calibration documentation is included.
Why Choose the PXI-4022?
- Adds six-wire guarded resistance capability to compatible PXI DMM systems
- Provides three ranges for sensitive current measurements
- Offers low burden voltage on the 100 nA range
- Minimizes loading with high input impedance and low bias current
- Supports automated precision measurements in a modular PXI platform
- Uses low-leakage and low-thermal signal connections
- Integrates with NI-DMM and LabVIEW applications
- Supports in-circuit, insulation and semiconductor testing
Frequently Asked Questions
What is the PXI-4022?
The PXI-4022 is an NI guard and current amplifier module used with compatible PXI digital multimeters for six-wire resistance and sensitive low-current measurements.
Is the PXI-4022 a standalone digital multimeter?
No. It is a signal-conditioning and amplifier module. A compatible NI PXI digital multimeter is required to digitize its output and produce measurement results.
What current ranges does the PXI-4022 provide?
The module provides 1 mA, 10 µA and 100 nA current ranges.
What is a six-wire resistance measurement?
A six-wire measurement adds guard connections to the conventional four-wire force-and-sense configuration. The guard helps reduce current flowing through unwanted parallel resistance paths.
What is the PXI-4022 input impedance?
The voltage-amplifier input impedance is greater than 10 GΩ, helping minimize loading of high-impedance signal sources.
What is its input bias current?
The amplifier input bias current is specified at less than 5 pA.
What is the amplifier bandwidth?
The PXI-4022 provides at least 1 MHz amplifier bandwidth and a minimum slew rate of 40 V/µs.
Which driver controls the PXI-4022?
The PXI-4022 is configured through the NI-DMM driver. Software and operating-system compatibility should be confirmed for legacy systems.
Which accessories are available?
Compatible accessories include the 779410-01 low-leakage, low-thermal cable set and the 779499-01 low-leakage, low-thermal connectivity set.
What is the PXI-4022 part number?
The standard NI part number for the PXI-4022 is 779614-01.
Request a Quote for the PXI-4022
Contact us for current availability, condition, calibration status and pricing for the PXI-4022 6-Wire Guard and Current Amplifier Module. We can also help identify compatible PXI digital multimeters, low-leakage cable sets, connectivity accessories, chassis and related precision measurement modules.
