Formula
For a two-wire DC loop, voltage drop is approximately Vdrop = 2 x L x I x Rm, where L is one-way cable length, I is load current, and Rm is conductor resistance per meter.
VoltCheck24 Engineering Calculator
24V Voltage Drop Calculator
Estimate loop resistance, voltage drop, terminal voltage, and brownout margin for PLC sensors, solenoids, relays, and DC control circuits.
Use Cases
Use this page when checking long M12 sensor runs, remote I/O stations, valve manifolds, relay coils, safety circuits, or 24V distribution inside a control panel.
Engineering Note
Keep final terminal voltage above the device minimum voltage with margin for inrush, ambient temperature, connector resistance, and future expansion.
FAQ
What is an acceptable voltage drop for a 24V control circuit?
Many industrial control designs target 3% to 5% in normal operation, but the final limit should follow the project specification and device datasheets.
Why does a 24V sensor reset even when the power supply is healthy?
Long cable resistance, shared commons, solenoid inrush, and connector losses can pull the terminal voltage below the sensor minimum for a short time.