# Power Supply Voltage

This chapter explains the Bus Voltage: display and the Min Bus Voltage: and Max Bus Voltage: settings in the Power Supply Voltage window. Verify the power-supply specifications and current bus-voltage state before changing either threshold.

## Before You Begin

Item | What to Check
--- | ---
Device state | Stop motion and disable the drive before changing protection parameters. Make sure the load is supported and the mechanism cannot move unexpectedly when a threshold changes.
Parameter source | Use protection thresholds from project delivery documents, device specifications, or verified field records. Do not copy parameters from an unknown device.
Original-value backup | Click Refresh to read and record the current values before clicking Apply, so you can restore the last verified configuration if a problem occurs.
Applicability | This window alone cannot confirm model, firmware, or hardware applicability. If an item is missing, read-only, or cannot be written, first check the documentation for the current model and the supported firmware range.

High-risk operation: Apply on a safety page writes protection parameters to the controller, and some are persistent. Stop motion, disable the drive, and secure the load before making changes. Do not change protection thresholds while the device is moving or enabled.

## Power Supply Voltage

Item | Description | Recommendations
--- | --- | ---
Bus Voltage: | Read-only display of the current bus voltage. | Check that the actual voltage is stable before adjusting thresholds. Do not change the protection range while the power supply is abnormal.
Min Bus Voltage: | Sets the lower bus-voltage protection limit. A typical range is 20,000 mV to 44,000 mV. | As a reference, use 90% of the rated bus voltage. The final value must follow the drive specifications and power-supply conditions.
Max Bus Voltage: | Sets the upper bus-voltage protection limit. A typical range is 28,000 mV to 55,000 mV. | As a reference, use 110% of the rated bus voltage. This value must not be lower than the minimum permitted bus voltage.

Use the Power Supply Voltage window to view Bus Voltage: and configure its permitted range.

Power settings may differ by model. If a bus-voltage setting is missing, read-only, or cannot be written, check the supported range for the current model in the delivery documentation.

## High-Risk Operations

Operation | Risk | Recommendation
--- | --- | ---
Adjust the bus-voltage limits | May make overvoltage or undervoltage protection too permissive or too restrictive. | Set according to the drive and power-supply specifications, then monitor the warning state.
Adjust current limits | May affect output capability and overload protection. | Make small adjustments within the device specifications and monitor current and faults.
Adjust torque limits | May affect output capability, holding force, and mechanical safety limits. | Set according to the device specifications and mechanical-safety requirements.
Adjust temperature limits | May change the temperature-protection trip point. | Set according to the device specifications. Do not raise the threshold merely to suppress a warning.
Adjust position limits | May affect travel limits and mechanical safety. | Verify both directions and the limits at low speed over a short travel.
Adjust speed limits or emergency-stop deceleration | May affect stopping distance, impact, and protection triggering. | Verify against the available safety distance and load inertia.
Adjust stall thresholds or force-control limits | May delay stall protection, cause false warnings, or produce abnormal output. | Start with verified parameters and validate under light load before normal operation.

## Troubleshooting

Symptom | Recommended Action
--- | ---
Frequent warnings or stops after applying settings | Restore the last verified parameters. Check whether thresholds are too narrow, the load has changed, or the power supply is abnormal.
Protection does not trigger as expected | Check whether thresholds are too wide and whether the current control mode matches the actual feedback. Confirm that the firmware supports the parameter.
Some items are missing or read-only | Confirm that the current model, hardware version, firmware version, and project delivery documents support this setting.
Read or write fails | Do not apply repeatedly. First verify the connection, device ID, firmware version, project documentation, and current error state.
Position or speed limits do not match motion behavior | Cross-check Motion, Motor Settings, Feedback Settings, Control Mode, and the protection parameters on this page to avoid conflicting settings.