National Instruments RMX-4125 User Manual

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Troubleshooting
This appendix lists a few troubleshooting situations and their corresponding solutions.
If none of the items apply to your case, we recommend that you initialize the RMX
programmable power supply to its factory default settings by holding down the SHIFT +
LOCAL keys while turning the power switch on. If this does not correct the problem, contact
National Instruments.
The Power Does Not Turn On
The RMX programmable power supply does not operate when the POWER switch is
turned on.
Is the power cord broken? Exchange the power cord with a new one.
Is the power cord connected correctly? Connect the power cord correctly.
No Output is Generated
No output is generated even when the OUTPUT switch is turned on.
Is the output voltage set to 0 V and the output current set to 0 A? Turn the knobs to set the output
voltage and output current to the required values.
Are you using an external contact to turn output on and off? Use the external contact to turn
output on. If not, set the external control parameter for turning output on and off to “off”
(CF09: oFF).
Even when the RMX programmable power supply is configured so that output is turned
on at power on, the output is turned off immediately after the power is turned on.
Has the overvoltage protection (OVP) function been activated? Limit the set output voltage
(CF15: on). If you do not limit the set output voltage (CF15: oFF), set the OVP to a value that is
higher than the set voltage.
Has the overvoltage protection2 (OVP2) function been activated? A voltage that is greater than
or equal to the rated output may be being applied to the RMX programmable power supply.
Check the voltage that is being applied.
Has the overheat protection (OHP/ OHP2) function been activated? The internal temperature is
abnormally high. Check the operating conditions. After you have removed the cause of the

National Instruments RMX-4125 Specifications

General

Power Rating	1250 W
Input Voltage	100 to 240 VAC
Input Frequency	50/60 Hz
Operating Temperature Range	0 to 50 °C
Storage Temperature Range	-20 to 70 °C
Form Factor	1U Rackmount
Control Interface	Ethernet

Summary

Basic Functions

Panel Operations

Output Operations

Protection Functions and Alarms

Details various protection mechanisms like OVP, OCP, and alarm indications to safeguard the unit and load.

CONFIG Settings

External Control

Output Terminal Insulation

Controlling the Output Voltage

Explains how to control the output voltage externally using voltage or resistance sources.

Controlling the Output Current

Details external control of output current using voltage or resistance sources.

Controlling the Output On and Off States

Describes how to remotely control the output state (on/off) using external contacts.

Parallel/Series Operation

Master-Slave Parallel Operation

Guides on connecting and operating multiple units in parallel for increased current capacity.

Series Operation

Provides instructions for connecting and operating units in series to increase output voltage.

Maintenance

Calibration Procedure

Outlines the steps for calibrating the RMX programmable power supply to ensure measurement accuracy.

Troubleshooting

The Power Does Not Turn On

Helps diagnose and resolve issues where the power supply fails to turn on when the power switch is activated.

No Output is Generated

Guides users on troubleshooting scenarios where the output terminals show no voltage or current.

Unable to Set the Output Voltage or Output Current Correctly

Addresses issues preventing correct setting of output voltage or current values due to protection limits.

Output is Unstable

ALARM LED Lights When the OUTPUT Switch is On

Unable to Perform Panel Operations

Unable to Perform Remote Control