RMX-4004 2-Channel DC Electronic Load Module
The RMX-4004 is a two-channel programmable DC electronic load module designed for power supply validation, power converter characterization and automated production testing. It provides one 30 W, 5 A channel and one high-power channel capable of sinking up to 250 W and 40 A.
Both channels support input voltages from 0 V to 80 V. The asymmetric channel configuration allows engineers to test a primary power rail and a lower-power auxiliary rail with one electronic load module.
The RMX-4004 installs in an RMX-4000 two-slot or RMX-4002 four-slot electronic load mainframe. The mainframe supplies power, front-panel control and remote communication for the installed load modules.
RMX-4004 Product Overview
An electronic load absorbs power from a connected source and simulates the electrical behavior of the source’s intended load. Unlike a programmable power supply, the RMX-4004 does not generate power; it draws controlled current from power supplies, batteries, converters and other DC sources under test.
The two RMX-4004 channels can operate using constant-current, constant-resistance, constant-voltage or constant-power control. Static and dynamic functions allow engineers to evaluate both steady-state regulation and transient response.
Multiple load modules can be installed in one mainframe to increase channel count or support different voltage, current and power requirements. Compatible channels can also be operated in supported parallel configurations when additional power dissipation is required.
Key Features of the RMX-4004
Two Independent Electronic Load Channels
The RMX-4004 combines two channels with different current and power capabilities:
- Lower-power channel: up to 30 W and 5 A
- Higher-power channel: up to 250 W and 40 A
- Voltage range: 0 V to 80 V on both channels
This configuration is useful for testing devices with a high-power main output and a lower-power standby, bias or auxiliary output.
Up to 250 W Power Dissipation
The higher-power channel can dissipate up to 250 W within its documented voltage-current operating area. The maximum voltage, current and power limits cannot necessarily be reached at the same operating point.
Up to 40 A Current Capability
The high-current channel supports measurements and load operation up to 40 A. The lower-power channel supports currents up to 5 A, providing better suitability for auxiliary power rails and lower-current outputs.
0 V to 80 V Input Range
Both channels support DC sources with voltages up to 80 V. Applications include low-voltage power supplies, DC-DC converters, battery systems, industrial power rails and telecommunications equipment.
Constant-Current Mode
In constant-current mode, the RMX-4004 draws the programmed current while the source voltage changes. This mode is commonly used for power supply load regulation, battery discharge and current-limit testing.
Constant-Resistance Mode
Constant-resistance mode changes the load current according to the measured input voltage, simulating the behavior of a resistive load.
Constant-Voltage Mode
In constant-voltage mode, the electronic load adjusts the current it draws to maintain the programmed voltage at its input. This mode is useful for testing current sources and selected battery or charging applications.
Constant-Power Mode
Constant-power mode automatically adjusts current as the source voltage changes to maintain the selected power level, subject to the channel’s voltage, current and power limits.
Static and Dynamic Loading
Static operation applies a stable load level for regulation, efficiency and endurance testing. Dynamic operation switches between programmed load conditions to evaluate the transient response of a power supply or converter.
Go/NoGo Testing
Configurable Go/NoGo limits allow the system to evaluate whether measured values remain within defined acceptance ranges. This function is useful for repetitive production inspection and quality-control tests.
RMX-4004 Technical Specifications
| Product Model | RMX-4004 |
|---|---|
| NI Part Number | 786530-01 |
| Product Type | Programmable DC Electronic Load Module |
| Number of Channels | 2 |
| Channel 1 Maximum Power | 30 W |
| Channel 1 Maximum Current | 5 A |
| Channel 2 Maximum Power | 250 W |
| Channel 2 Maximum Current | 40 A |
| Input Voltage Range | 0 V to 80 V |
| Operating Modes | CC, CR, CV/CV+CC and CP |
| Load Operation | Static and dynamic |
| Current Ranges | Low and high ranges, channel dependent |
| Measurement Functions | Voltage, current and calculated power |
| Test Functions | Go/NoGo limits, protection and saved configurations |
| Compatible Mainframes | RMX-4000 and RMX-4002 |
| Mainframe Control Interfaces | USB, Ethernet LAN and RS232 |
| Programming Support | SCPI, LabVIEW and NI-VISA |
| Parallel Operation | Supported with compatible channels and configurations |
| Lifecycle Status | Active |
RMX-4004 Channel Configuration
| Channel | Maximum Voltage | Maximum Current | Maximum Power | Typical Use |
|---|---|---|---|---|
| Lower-Power Channel | 80 V | 5 A | 30 W | Standby, bias and auxiliary power rails |
| Higher-Power Channel | 80 V | 40 A | 250 W | Main power rails and high-current outputs |
The maximum voltage, current and power values define the boundaries of each channel’s operating area. Users should verify that the intended test point falls within all three limits.
How the RMX-4004 Works
The device under test supplies DC power to the electronic load. The RMX-4004 controls internal power devices to draw the amount of current necessary to maintain the selected operating condition.
For example, in constant-current mode the load draws a programmed current. In constant-power mode, it continuously adjusts current according to the measured voltage so the absorbed power remains near the programmed value.
The mainframe displays the measured voltage and current and provides communication between the load module and the automation computer. Absorbed electrical energy is converted into heat and removed by the mainframe’s cooling system.
RMX-4000 and RMX-4002 Mainframe Requirements
The RMX-4004 is a load module and cannot operate independently. It must be installed in a compatible RMX electronic load mainframe.
- RMX-4000 – Accommodates up to two electronic load modules
- RMX-4002 – Accommodates up to four electronic load modules
The mainframe provides AC power, cooling, front-panel controls and remote communication. When configuring a system, verify the number and type of load modules, mainframe capacity and required rack space.
Remote Control and Automation
The RMX-400x mainframes support programmatic control through USB, RS232 and Ethernet LAN. These interfaces allow the installed RMX-4004 channels to be configured and monitored by an automated test application.
The NI RMX-400x Electronic Load Driver provides LabVIEW support and abstracts commonly used SCPI commands. NI-VISA or compatible command-based environments can also be used.
Typical automated operations include:
- Setting the electronic load mode
- Programming current, resistance, voltage or power
- Switching the load input on and off
- Reading measured voltage and current
- Generating dynamic load steps
- Monitoring alarms and protection events
- Performing automated pass/fail evaluation
Dynamic Load Testing
Dynamic loading allows engineers to switch between load levels and observe how quickly the connected power source recovers. This is important for evaluating voltage undershoot, overshoot, control-loop stability and transient response.
Typical dynamic tests include:
- Processor load-step simulation
- DC-DC converter transient response
- Power supply recovery-time measurement
- Battery response to changing loads
- Current-limit and protection validation
Parallel Operation for Higher Power
Compatible RMX electronic load channels and modules can be connected in supported parallel configurations to increase total current and power capability. This provides a scalable approach for projects whose power requirements may increase over time.
Parallel operation requires correct current sharing, matched settings and suitable load wiring. Confirm the configuration in the RMX-400x user manual before connecting channels or mainframes in parallel.
Typical Applications
- AC-DC power supply validation
- DC-DC converter testing
- Battery discharge testing
- Battery charger characterization
- Power adapter functional testing
- Voltage regulator testing
- Telecommunications power testing
- Automotive electronic power-rail validation
- Industrial power system testing
- Production quality inspection
- Reliability and burn-in testing
- Multirail power supply testing
Protection and Operating Limits
The RMX-400x platform includes configurable protection functions to protect the load module and connected system. Depending on the selected operating mode and configuration, these can include overvoltage, overcurrent, overpower and overtemperature protection.
Before enabling the load:
- Confirm the polarity of the connected source
- Use cables rated for the maximum current
- Verify that the test point is within the operating area
- Configure current and power limits before connecting the source
- Keep the mainframe ventilation openings unobstructed
- Use remote sensing when cable voltage drop affects accuracy
RMX-4004 Troubleshooting
The RMX-4004 Is Not Detected
Confirm that the load module is fully installed in a compatible RMX-4000 or RMX-4002 mainframe. Power-cycle the mainframe and check the installed module configuration.
The Load Does Not Draw the Programmed Current
Verify that the load input is enabled and that the source voltage exceeds the minimum voltage required for the programmed operating point. Also check the channel’s current and power limits.
The Channel Enters Overpower Protection
Calculate the absorbed power using input voltage multiplied by current. Reduce the programmed current or voltage so the operating point remains within the 30 W or 250 W channel limit.
Measured Voltage Is Lower Than Expected
High current can produce significant voltage drop in the load cables. Use short, adequately sized cables and correctly connected remote-sense leads where applicable.
Remote Communication Does Not Work
Check the USB, LAN or RS232 configuration on the mainframe. Verify that the driver or NI-VISA software is installed and that the application is addressing the correct instrument and channel.
The Module Shuts Down During Long Tests
Inspect the mainframe airflow and ambient temperature. Continuous high-power operation generates substantial heat and requires unobstructed cooling.
RMX-4004 vs RMX-4003
The RMX-4003 provides two matched channels rated for up to 100 W and 20 A each. The RMX-4004 instead combines a 30 W, 5 A channel with a 250 W, 40 A channel.
Choose the RMX-4003 for two similar power rails. Choose the RMX-4004 when the device under test has one high-power output and one lower-power auxiliary output.
RMX-4004 vs RMX-4005
The RMX-4005 is a single-channel electronic load supporting up to 350 W, 80 V and 70 A. It provides more current and power than the higher-power RMX-4004 channel but does not provide a second independent load channel.
Choose the RMX-4005 for a single high-current power rail. Choose the RMX-4004 when two independently controlled channels are required.
RMX Electronic Load Comparison
| Model | Channels | Maximum Power | Maximum Voltage | Maximum Current |
|---|---|---|---|---|
| RMX-4003 | 2 | 100 W per channel | 80 V | 20 A per channel |
| RMX-4004 | 2 | 30 W and 250 W | 80 V | 5 A and 40 A |
| RMX-4005 | 1 | 350 W | 80 V | 70 A |
| RMX-4006 | 1 | 350 W | 500 V | 10 A |
How to Select the Right Electronic Load
Choose the RMX-4004 when the application requires:
- Two independently controlled DC load channels
- One high-power and one auxiliary channel
- Input voltages no higher than 80 V
- Current capability up to 40 A
- CC, CR, CV and CP operating modes
- Dynamic transient testing
- Integration with an RMX-4000 or RMX-4002 mainframe
Select another model if the application needs matched channel power, more than 40 A, more than 250 W on one channel or input voltages above 80 V.
Recommended Related Products
- RMX-4000 Electronic Load Mainframe – Required two-slot mainframe for operating RMX-400x load modules.
- RMX-4002 Electronic Load Mainframe – Four-slot mainframe for higher channel count and mixed load configurations.
- RMX-4003 Electronic Load Module – Two matched 100 W, 20 A load channels.
- RMX-4005 Electronic Load Module – Single-channel 350 W, 70 A option for high-current testing.
- RMX-4006 Electronic Load Module – Single-channel 500 V electronic load for higher-voltage applications.
- RMX-4123 Programmable Power Supply – 750 W programmable DC source for high-voltage automated power testing.
Why Choose the RMX-4004?
- Two independent electronic load channels
- 30 W and 250 W channel configuration
- Current capability up to 40 A
- Input voltages up to 80 V
- CC, CR, CV and CP modes
- Static and dynamic load testing
- Go/NoGo production test capability
- USB, LAN and RS232 control through the mainframe
- Expandable modular RMX architecture
- Active NI lifecycle status
Frequently Asked Questions
What is the RMX-4004 used for?
The RMX-4004 is used to test power supplies, DC-DC converters, batteries, chargers and multirail power systems by applying programmable DC load conditions.
Does the RMX-4004 generate power?
No. It is an electronic load that absorbs power from a connected DC source. A programmable power supply is required when the test system needs to generate DC power.
How many load channels does it provide?
It provides two independently controlled channels: one rated for up to 30 W and 5 A and another rated for up to 250 W and 40 A.
What is the maximum input voltage?
Both channels support input voltages up to 80 V.
Can the RMX-4004 operate independently?
No. It must be installed in an RMX-4000 two-slot or RMX-4002 four-slot electronic load mainframe.
Which operating modes are supported?
The RMX-4004 supports constant-current, constant-resistance, constant-voltage and constant-power modes.
Does it support transient load testing?
Yes. Dynamic operation can switch between load levels to evaluate the transient response of a power source.
Can multiple RMX-4004 modules be connected in parallel?
Compatible load channels and modules can be used in supported parallel configurations to increase total current and power capacity. Follow the RMX-400x user manual when designing the connection.
Which communication interfaces are supported?
The compatible RMX mainframes support USB, Ethernet LAN and RS232 control.
What is the NI part number for the RMX-4004?
The standard orderable NI part number is 786530-01.
Is the mainframe included?
The RMX-4004 product is a load module. Confirm whether an RMX-4000 or RMX-4002 mainframe, cables and software are included or must be ordered separately.
Request a Quote for the RMX-4004
Contact us for current availability, lead time and project pricing for the RMX-4004 2-Channel DC Electronic Load Module. We can also help select a compatible RMX-4000 or RMX-4002 mainframe and compare alternative load modules for your power test system.
