Change a VIPER Voltage Setpoint

Start with a connected power supply and updating telemetry. Export the configuration before changing settings.

Check the connected load's voltage limits before applying a setpoint.

The interface’s allowed range does not guarantee safe operation of the load.

Allowed range

Standard VIPER limits setpoints to +/-10% of nominal. Use the range displayed for the selected device.

Rail	Example nominal voltage	Allowed range for that nominal
VS1	12.00 V	10.80 to 13.20 V
VS2	3.35 V	3.02 to 3.69 V
VS3	5.00 V	4.50 to 5.50 V
3.3 V Aux	3.30 V	2.97 to 3.63 V
+12 V Aux	12.00 V	10.80 to 13.20 V
-12 V Aux	-12.00 V	-13.20 to -10.80 V

The SRC build uses a different VS1 lower limit.

Change the value

1. Open Configure and select the target slot.
2. Select Read from Device.
3. Record the rail’s current setpoint.
4. Enter the new voltage in that rail’s setpoint field.
5. Review all displayed rail values and current limits.
6. Select Apply on the rail’s card.
7. Check for write errors.

Some devices apply all rail setpoints together. Review every field before applying a change.

Verify and restore

1. Open Telemetry and check the selected rail’s voltage.
2. Confirm the output with a meter.
3. After testing, enter the original setpoint and select Apply.
4. Verify the restored voltage.

Written setpoints persist through input-power cycles.

Problems

Symptom	Action
Field turns red	Enter a value within the displayed range.
Apply is unavailable	Select Read from Device, then enter a changed value.
Voltage does not change	Check output enable, inhibit, fault status, and write errors.
Write fails	Check communication and the hardware write-protection switch.
Meter and telemetry disagree	Check the measurement connections before changing calibration.

See Hardware setup for write-protection switch positions. Contact NAI Support if the applied setting or measured output remains incorrect.