RMX-4122 750 W 230 V 10 A Programmable DC Power Supply
The RMX-4122 is a single-channel, 750 W programmable DC power supply designed for high-voltage device validation, power-converter testing, industrial electronics and automated production systems. Its autoranging output architecture supports flexible voltage and current combinations with rated capabilities up to 230 VDC or 10 A.
The RMX-4122 occupies one full-width 1U rack space and can be operated locally through its front-panel display, buttons and rotary controls. LAN, USB, RS232 and analog interfaces allow the supply to be integrated into computer-controlled and automated test systems.
Key Features of the RMX-4122
- 750 W maximum output power
- 230 V rated output voltage
- 10 A rated output current
- Flexible autoranging output architecture
- 0 V to 241.5 V programmable voltage range
- 0 A to 10.5 A programmable current range
- Single programmable DC output channel
- Constant-voltage and constant-current operation
- Four-wire remote sensing
- Up to 5 V remote-sense compensation per line
- Programmable overvoltage protection
- Programmable overcurrent protection
- Programmable undervoltage limit
- Three front-panel preset memories
- LAN, USB and RS232 communication
- External analog programming and monitoring
- Parallel operation with up to four identical units
- Series operation with up to two identical units
- Compact 1U full-width rack-mount design
RMX-4122 Technical Specifications
| Product Model | RMX-4122 |
|---|---|
| Part Number | 784763-01 |
| Product Type | Programmable rack-mount DC power supply |
| Number of Output Channels | 1 |
| Rated Output Power | 750 W |
| Rated Output Voltage | 230 VDC |
| Rated Output Current | 10 A |
| Voltage Setting Range | 0 V to 241.5 V |
| Current Setting Range | 0 A to 10.5 A |
| Voltage Setting Accuracy | ±(0.05% of setting + 0.05% of rated voltage) |
| Current Setting Accuracy | ±(0.5% of setting + 0.1% of rated current) |
| Voltage Line Regulation | ±25 mV |
| Voltage Load Regulation | ±25 mV |
| Current Line Regulation | ±3 mA |
| Current Load Regulation | ±7 mA |
| Voltage Transient Response | 7 ms or less under specified load-change conditions |
| Voltage Ripple and Noise | 120 mV peak-to-peak; 25 mV RMS |
| Current Ripple and Noise | 30 mA RMS under specified conditions |
| Voltage Rise Time | 100 ms |
| Voltage Fall Time | 150 ms at rated load; 1,500 ms at no load with bleeder enabled |
| Remote-Sense Compensation | Up to 5 V per output line |
| Overvoltage Protection Range | 23 V to 257.6 V |
| Fixed Secondary Overvoltage Protection | 276 V |
| Overcurrent Protection Range | 1 A to 11.2 A |
| Undervoltage Limit Range | 0 V to 241.5 V |
| AC Input Rating | 100 VAC to 240 VAC, 50 Hz to 60 Hz, single phase |
| AC Input Voltage Range | 85 VAC to 265 VAC |
| AC Input Frequency Range | 47 Hz to 63 Hz |
| Maximum AC Input Power | 1,100 VA at 100 VAC |
| Maximum Inrush Current | 70 A peak or less under specified conditions |
| LAN Interface | 10Base-T or 100Base-TX Ethernet, IPv4 |
| Additional Interfaces | USB, RS232 and analog control |
| Parallel Operation | Up to four identical RMX-4122 units including the master |
| Series Operation | Up to two identical RMX-4122 units |
| Preset Memory | Three groups of output and protection settings |
| Output-to-Ground Isolation | ±500 V maximum |
| Rack Size | 1U, full rack width |
| Weight | Approximately 7.5 kg |
| Cooling Method | Forced-air fan cooling |
| Operating Temperature | 0°C to 50°C |
| Operating Humidity | 20% to 85% RH, noncondensing |
| Maximum Altitude | 2,000 m |
RMX-4122 Part Number and Accessories
| Item | Part Number | Description |
|---|---|---|
| RMX-4122 | 784763-01 | 750 W, 230 V, 10 A single-channel programmable DC power supply |
| U.S. IEC Power Cord | 763830-01 | 125 VAC, 15 A AC power cord |
| China IEC Power Cord | 784686-01 | 250 V, 10 A AC power cord |
| Korea IEC Power Cord | 784685-01 | 240 V, 10 A right-angle power cord |
| Japan IEC Power Cord | 786377-01 | 125 VAC, 12 A AC power cord |
| Taiwan IEC Power Cord | 787642-01 | 125 VAC, 15 A AC power cord |
| European IEC Power Cord | 763067-01 | 240 V, 10 A right-angle power cord |
| India IEC Power Cord | 763072-01 | 250 V, 10 A AC power cord |
Select the AC power cord according to the installation country, facility voltage and connector standard. The output cables, crimp terminals, fixture insulation and protective components must be rated for the maximum voltage and current.
750 W Autoranging Output Architecture
The RMX-4122 operates across a broad range of voltage and current combinations while limiting total output power to 750 W. This autoranging architecture provides more flexibility than a conventional fixed-range power supply.
The rated 230 V and 10 A limits cannot be delivered simultaneously because that operating point would require 2,300 W. At 230 V, the available current is approximately 3.26 A. At 10 A, the available voltage is approximately 75 V.
Before selecting the RMX-4122, confirm that every required DUT operating point falls within the 750 W power envelope.
230 V Rated Output Voltage
The RMX-4122 has a rated output voltage of 230 V and a programmable setting range extending to 241.5 V. It is intended for high-voltage DC circuits, power converters, industrial electronics and device characterization.
The wide voltage range supports tests that cannot be performed with lower-voltage supplies such as the RMX-4120 or RMX-4121. High-voltage fixtures must provide appropriate insulation, protective covers, grounding and operator protection.
10 A Rated Output Current
The supply provides a rated output current of 10 A and a programmable setting range extending to 10.5 A. This combination supports high-voltage devices requiring several hundred watts of input power.
Output current remains limited by the 750 W maximum power rating. At voltages above 75 V, the maximum available current progressively decreases.
Constant-Voltage Operation
In constant-voltage mode, the RMX-4122 regulates the programmed voltage while allowing the DUT to draw current up to the configured current setting. The CV indicator shows when voltage regulation is active.
If the DUT requests more current than the configured value, the supply transitions to constant-current operation. This limits the current delivered during startup, overload or fault conditions.
Constant-Current Operation
In constant-current mode, the RMX-4122 regulates the output current while the voltage changes according to load resistance. The programmed voltage setting establishes the maximum permitted output voltage.
This operating mode can be used for controlled component testing, power-device conditioning and applications that require a regulated DC current.
Four-Wire Remote Sensing
The RMX-4122 supports remote sensing to compensate for voltage drop in the output cables and fixture wiring. Separate sense conductors measure voltage directly at the DUT.
The supply can compensate for as much as 5 V of voltage drop on each output line. However, its output terminals remain limited to 105% of the rated voltage and the total output remains limited to 750 W.
Remote-Sense Wiring
Use twisted-pair or shielded conductors for the positive and negative sense connections. Keep sense wiring away from switching nodes and electrically noisy power cables.
Always connect the sense leads with the correct polarity. Incorrect or disconnected sense wiring may cause unstable output or an unexpected increase in terminal voltage.
Voltage Regulation and Dynamic Response
Voltage line regulation and load regulation are specified at ±25 mV. The voltage transient-response time is 7 ms or less under the official load-change conditions.
Actual system performance depends on cable length, remote-sense wiring, load dynamics and external capacitance. Dynamic performance should be verified with the final production fixture and DUT.
Voltage Ripple and Noise
The RMX-4122 specifies voltage ripple and noise of 120 mV peak-to-peak and 25 mV RMS under the applicable bandwidth and load conditions.
For noise-sensitive measurements, use correct grounding, shielded measurement wiring and separation between the power output and low-level instrument signals.
Programmable Overvoltage Protection
The primary overvoltage protection threshold can be programmed from 23 V to 257.6 V. When the threshold is exceeded, the RMX-4122 disables its output, displays an OVP message and activates the alarm indicator.
A secondary fixed overvoltage protection threshold is set at 276 V, equivalent to 120% of the rated output voltage. Configure the primary threshold below the DUT’s maximum safe voltage.
Programmable Overcurrent Protection
The overcurrent protection threshold can be configured between 1 A and 11.2 A. When OCP activates, the supply shuts down its output and reports an alarm condition.
OCP is a shutdown feature and should not be confused with normal constant-current regulation. Configure the normal current setting for expected operation and use OCP as an additional fault limit.
Undervoltage Limit
The undervoltage limit prevents the supply from being programmed below a defined voltage. The available setting range extends from 0 V to 241.5 V.
This function is useful when a device could operate incorrectly, draw excessive current or enter an unsafe state below its minimum supply voltage.
Three Preset Memories
The RMX-4122 can store three groups of frequently used settings. Each preset can contain voltage, current, OVP, OCP and undervoltage-limit values.
Preset memory simplifies repetitive laboratory and production work while reducing the risk of configuration errors between different DUT types.
Front-Panel Control
The front panel provides separate displays and controls for configuring and monitoring output voltage, current and power. Status indicators show constant-voltage, constant-current, alarm, output and remote-control conditions.
A key-lock function can prevent accidental changes during automated operation. Local controls remain useful for maintenance, fixture verification and initial DUT setup.
LAN Remote Control
The Ethernet interface supports 10Base-T and 100Base-TX communication over IPv4. LAN connectivity allows the RMX-4122 to operate in production racks, shared laboratories and remotely controlled test systems.
Configure the IP address, subnet settings and required communication parameters before connecting the software. Network security must permit communication between the controller and instrument.
USB Connectivity
The USB interface provides a direct computer connection for benchtop development and automated systems with a nearby controller.
Install the appropriate driver and VISA communication software before connecting the instrument. Use a direct USB connection during initial troubleshooting.
RS232 Serial Communication
The RS232 interface supports integration with industrial controllers and established test systems that use serial communication.
Confirm that the computer and RMX-4122 use matching baud rate, data format and termination settings. An incorrect serial configuration can prevent command responses.
External Analog Control
The analog interface allows external voltage or resistance signals to control the RMX-4122 output. Analog monitor signals can be used by an external controller to observe voltage, current and operating status.
Verify interface scaling, grounding and maximum input ratings before applying an external control signal.
Parallel Operation
Up to four identical RMX-4122 units, including the master, can be configured for supported parallel operation. Parallel operation increases total current and power while retaining the model’s voltage range.
Only identical models should be combined. All power cables, sharing connections, AC circuits and protective devices must support the combined system capacity.
Series Operation
Up to two identical RMX-4122 units can be used in a supported series configuration to increase total output voltage. The complete arrangement must remain within the output-to-ground isolation limits.
Series operation can create hazardous voltage substantially above the rating of one unit. Use appropriate insulation, enclosures, interlocks and operator-protection procedures.
Output Isolation and Grounding
The RMX-4122 supports output-to-ground isolation up to ±500 V maximum. Either the positive or negative output may be grounded when the complete configuration remains within the applicable isolation limits.
Review the grounding arrangement before connecting other instruments. Oscilloscope, electronic-load and measurement-device grounds can unintentionally change the output’s relationship to earth ground.
High-Voltage Safety
The RMX-4122 can generate hazardous DC voltage. The output should be enclosed, covered and inaccessible during operation. Turn off the AC input and confirm that the output has discharged before touching terminals or modifying wiring.
The output terminal cover must be installed before the supply is energized. Use cables, connectors, relays and fixtures with voltage ratings appropriate for the maximum possible system output.
Typical RMX-4122 Applications
- High-voltage DC-DC converter testing
- Power-electronics development
- Industrial power-supply validation
- Motor-drive electronics testing
- Inverter subsystem testing
- High-voltage component characterization
- Battery-stack simulation
- Automotive and electric-vehicle electronics
- Aerospace power-system testing
- Electronic device validation
- Automated production testing
- Burn-in and reliability testing
- Laboratory automation
- Rack-mounted automated test equipment
High-Voltage Converter Testing
The RMX-4122 can supply programmable input power to high-voltage DC-DC converters and power-electronic assemblies. Software can sweep voltage and observe converter efficiency, regulation and protection behavior.
A compatible electronic load can be installed on the converter output to form a complete source-and-load test system.
Industrial Electronics Testing
The 230 V range supports industrial controllers, drive electronics, power supplies and equipment using high-voltage DC buses. Programmable voltage and current limits help protect prototypes during initial energization.
Inductive devices may return energy or create voltage transients when their current is interrupted. External suppression or energy-absorption hardware may be necessary.
Battery-Stack Simulation
The RMX-4122 can reproduce the unidirectional DC output of a battery stack within its 230 V and 750 W operating limits. This allows engineers to test battery-powered converters and control electronics without using a physical battery for every procedure.
Applications requiring bidirectional energy flow, regenerative charging or battery-impedance simulation require additional specialized equipment.
Burn-In and Reliability Testing
The supply can power electronic devices during extended burn-in, thermal and reliability tests. LAN or other remote interfaces allow the output state and alarms to be monitored by automated software.
Maintain adequate airflow and verify that all wiring, terminals and protective equipment are suitable for continuous high-voltage operation.
Calibration and Warm-Up
The RMX-4122 ships with a calibration utility. The official specifications assume a 30-minute warm-up with current flowing and correct calibration in a 23°C ±5°C environment.
Select a calibration interval based on NI recommendations, usage level, required uncertainty and the organization’s quality procedures.
RMX-4122 Troubleshooting
The RMX-4122 cannot output 230 V at 10 A
The voltage and current ratings cannot be delivered simultaneously because the output is limited to 750 W. At 230 V, the maximum current is approximately 3.26 A. At 10 A, the maximum voltage is approximately 75 V.
The output voltage is lower than programmed
Check whether the supply has entered constant-current mode or reached its power limit. Inspect output cables and remote-sense wiring for excessive voltage drop or incorrect connections.
The power-limit indicator is active
The requested voltage and current combination exceeds 750 W. Reduce the output voltage, reduce the DUT current or use an appropriately configured higher-power supply.
The output voltage remains after output shutdown
Check the bleeder-circuit configuration and allow sufficient discharge time. Always measure the output and confirm a safe voltage before touching the terminals.
The remote-sense output is unstable
Check sense polarity, shielding and routing. Use twisted-pair or shielded wiring and consider a suitable capacitor at the DUT when permitted by NI guidance and the application.
The power supply reports an OVP alarm
Verify that the OVP threshold is above the intended operating voltage. Inspect sense wiring and check whether another source is applying voltage to the RMX-4122 output.
The power supply reports an OCP alarm
Check for a short circuit, excessive startup current or an incorrectly programmed OCP threshold. OCP shuts down the output and is separate from constant-current regulation.
The LAN connection does not work
Confirm the IP address, subnet mask, Ethernet cable and network link. Verify that firewall or network-security settings are not blocking communication.
The USB connection is not detected
Check the USB cable, computer port, instrument driver and VISA configuration. Connect the supply directly to the computer during troubleshooting.
The supply shuts down during continuous operation
Review the alarm message, AC input, rack airflow, cooling fan and ambient temperature. Ensure that ventilation openings are not obstructed.
RMX-4122 Comparison with Similar Programmable Power Supplies
| Model | Rated Output | Power | Best Suited For |
|---|---|---|---|
| RMX-4120 | 30 V, 75 A | 750 W | Low-voltage, very-high-current testing |
| RMX-4121 | 80 V, 28 A | 750 W | Medium-voltage power electronics and 48 V systems |
| RMX-4122 | 230 V, 10 A | 750 W | High-voltage converters and industrial electronics |
| RMX-4123 | 650 V, 3.5 A | 750 W | Very-high-voltage semiconductor and power-system testing |
| RMX-4126 | High-voltage, higher-power output | 1,500 W | Applications requiring more power than the RMX-4122 |
| RMX-4104 | Up to 100 V or 40 A, depending on configuration | Up to 864 W | Lower-voltage fixed-range rack systems |
RMX-4122 vs RMX-4121
The RMX-4121 provides up to 80 V and 28 A, while the RMX-4122 provides up to 230 V and 10 A. Both instruments offer 750 W autoranging output.
Select the RMX-4121 for medium-voltage devices requiring more current. Select the RMX-4122 when the test requires voltage above 80 V.
RMX-4122 vs RMX-4123
The RMX-4123 extends the rated voltage to 650 V but reduces rated current to 3.5 A. The RMX-4122 offers greater current capability for devices operating at 230 V or below.
Choose the RMX-4122 for high-voltage converters and industrial devices requiring up to 10 A. Choose the RMX-4123 for very-high-voltage DUTs requiring more than 230 V.
RMX-4122 vs RMX-4126
The RMX-4126 belongs to the 1,500 W power class and is intended for operating points that exceed the RMX-4122’s 750 W envelope.
Select the RMX-4122 when 750 W is sufficient and 1U rack density is important. Select the RMX-4126 for devices requiring higher total power.
Recommended Related Products
- RMX-4120 750 W 30 V 75 A Programmable Power Supply
- RMX-4121 750 W 80 V 28 A Programmable Power Supply
- RMX-4123 750 W 650 V Programmable Power Supply
- RMX-4126 1,500 W High-Voltage Programmable Power Supply
- RMX-4104 High-Power Programmable DC Power Supply
- PXIe-4136 High-Voltage Source Measure Unit
- View More NI PXI and PXI Express Modules
Selecting the Right RMX Power Supply
Choose the RMX-4122 when the application requires voltage up to 230 V, current up to 10 A and a maximum output-power envelope of 750 W. It is particularly suitable for high-voltage converters, industrial electronics and power-device testing.
Select the RMX-4121 when higher current is required below 80 V. Choose the RMX-4123 for voltage above 230 V or a corresponding 1,500 W model when the DUT requires more than 750 W.
Why Choose the RMX-4122?
- Provides 750 W from one programmable channel
- Supports voltage up to 230 VDC
- Supports current up to 10 A
- Offers flexible autoranging operation
- Compensates cable voltage drop through remote sensing
- Includes programmable OVP, OCP and UVL protection
- Supports LAN, USB, RS232 and analog control
- Supports series and parallel configurations
- Provides ±500 V output-to-ground isolation
- Occupies only 1U of rack height
Frequently Asked Questions
What is the RMX-4122?
The RMX-4122 is a single-channel, 750 W autoranging programmable DC power supply with rated output capabilities up to 230 V or 10 A.
Can the RMX-4122 output 230 V and 10 A simultaneously?
No. That operating point would require 2,300 W. Voltage and current combinations are limited to a maximum output power of 750 W.
What is the voltage setting range?
The programmable voltage setting range is 0 V to 241.5 V. The rated output voltage is 230 V.
What is the current setting range?
The programmable current setting range is 0 A to 10.5 A. The rated output current is 10 A.
Does the RMX-4122 support remote sensing?
Yes. Its remote-sense terminals can compensate for up to 5 V of voltage drop on each output line.
Can multiple RMX-4122 units be connected in parallel?
Yes. Up to four identical RMX-4122 units, including the master, can be used in a supported parallel configuration.
Can RMX-4122 units be connected in series?
Yes. Up to two identical units can be used in a supported series configuration, subject to grounding, insulation and isolation requirements.
Which communication interfaces are available?
The RMX-4122 supports LAN, USB, RS232 and external analog control.
Does the RMX-4122 include protection functions?
Yes. It provides programmable overvoltage protection, secondary fixed overvoltage protection, overcurrent protection, undervoltage limiting and thermal protection.
What is the RMX-4122 part number?
The standard NI part number for the RMX-4122 is 784763-01.
Request a Quote for the RMX-4122
Contact us for current availability, lead time and project pricing for the RMX-4122 750 W 230 V 10 A Programmable DC Power Supply. We can also help identify compatible AC power cords, high-voltage output wiring, rack accessories and related RMX power supplies for your automated test system.
