What Is a 0-5 VDC Signal and When Should You Use It?

A 0-5 VDC signal is an analog voltage output in which 0 volts represents the minimum of the measured range and 5 volts represents the maximum. You should choose it when your controller or data logger accepts a 0-5 V voltage input, the cable run is short, and the environment is electrically quiet. If any of those conditions fails, a current loop such as 4-20 mA is usually the better choice. BEC Controls Corp., for example, offers 0-5 VDC as one of several outputs (alongside 4-20 mA, 1-5 VDC, 0-10 VDC, 0-100 mV, and custom) on its custom-built pressure transmitters, so the output is selected at order time rather than added later.

How a 0-5 VDC Signal Works

The transmitter measures pressure and drives its output voltage in direct proportion to the measurement span. The relationship is linear:

• 0 V = lower range limit (often, but not always, zero pressure)
• 5 V = upper range limit (full scale)
• 2.5 V = midpoint of the range

For a transmitter ranged 0-100 PSI, 50 PSI produces 2.5 V, 75 PSI produces 3.75 V, and so on. The scaling is set by the transmitter's pressure range, not by the voltage itself, so the same 0-5 V output can represent any span the unit is built for.

Because 0 V is a valid reading, a 0-5 VDC signal cannot distinguish "zero pressure" from "no power" or "broken wire" by voltage alone. That is one of the practical differences from 4-20 mA, where the live zero at 4 mA separates a true zero reading from a dead loop.

0-5 VDC vs. Other Common Analog Outputs

The core trade-off: voltage outputs are simple and compatible with a wide range of low-cost controllers, but current loops hold their accuracy over distance and resist electrical interference far better. If your run is a few meters inside a panel, 0-5 VDC is often fine. If it crosses a plant floor near motors and drives, expect problems.

When 0-5 VDC Is the Right Choice

Pick 0-5 VDC when:

• Your controller, PLC analog card, or DAQ device has a 0-5 V input range and no current-input option.
• The transmitter sits close to the receiving device — short cable runs keep voltage drop and induced noise small.
• The environment is relatively clean electrically, or the cable is shielded and routed away from power wiring.
• You are working on an OEM product or bench setup where a simple voltage interface keeps the design and BOM straightforward.
• The application tolerates the lack of a live zero, or a separate fault check is acceptable.

Avoid it when the cable run is long, when the area has heavy electrical noise, or when losing the ability to detect a broken wire matters to the process.

Scaling 0-5 VDC to Engineering Units

The conversion is a straight linear map. For a transmitter ranged P_min to P_max:

Pressure = P_min + (V_measured / 5) × (P_max − P_min)

Example: a 0-5 VDC transmitter ranged 0-200 PSI reads 3.2 V.

Pressure = 0 + (3.2 / 5) × 200 = 128 PSI

In a controller, the same math becomes a scale-and-offset block: raw input 0-5 V maps to 0-200 PSI. Set the block's input range to match the actual voltage your device sees, not the ideal 0-5 V — a small offset at the input will otherwise shift every reading.

Common Pitfalls

• Ground loops. If the transmitter and the receiving device are grounded at different points, a circulating current can add an offset to the voltage reading. Using a single ground reference, or an isolated transmitter, avoids this.
• Voltage drop. Long or undersized cable adds resistance, so the voltage at the controller is lower than at the transmitter. Keep runs short and use adequate conductor size.
• Noise pickup. Unshielded cable run alongside AC power wiring couples interference into a voltage signal. Use shielded twisted pair and ground the shield at one end.
• Assuming 0 V means zero pressure. With no live zero, a reading of 0 V could mean zero pressure, a lost connection, or no power. Verify with a separate check if the distinction matters.
• Mismatched input range. Feeding a 0-5 V signal into a 0-10 V input (or vice versa) halves or doubles the apparent reading.

Troubleshooting a 0-5 VDC Signal

1. Check the supply. Confirm the transmitter has the correct excitation voltage and that it is within the unit's rated range. No supply means no output.
2. Measure at the transmitter first. Read the output voltage at the transmitter terminals, then at the controller. A difference points to voltage drop or a wiring fault in between.
3. Verify the pressure. Compare the voltage against a known pressure or a reference gauge to confirm the scaling is correct.
4. Inspect the wiring. Look for loose terminals, reversed polarity, damaged insulation, and shields grounded at both ends.
5. Isolate noise. If readings are erratic, temporarily route the cable away from power wiring or test with the transmitter connected to a clean bench supply to see whether the noise follows the wiring or the environment.
6. Confirm the input configuration. Make sure the controller's analog input is set for 0-5 V and not for a current loop or a different voltage range.

FAQ

Is 0-5 VDC the same as 1-5 VDC? No. Both are voltage outputs, but 1-5 VDC uses 1 V as its minimum, giving a live zero that lets the controller detect a fault. 0-5 VDC uses 0 V as the minimum.

Can I convert a 0-5 VDC signal to 4-20 mA? Yes, with a signal conditioner or converter. This is common when a voltage-output transmitter must reach a controller over a long run.

Does 0-5 VDC work over long cables? It can, but accuracy suffers from voltage drop and noise. For long runs, a current output is the more reliable choice.

Can a 0-5 VDC transmitter be custom-ranged? Yes. BEC Controls, for instance, builds pressure transmitters to order with 0-5 VDC among its output options and pressure ranges from 0.5" wc to 1500 PSI, with customization offered at no charge.