A guide to measurement signal types for sensors & instrumentation, including explanations, applications and choice of products with analog & digital signals.
Products by Signal Type
Select a sensor or instrument by input or output signal type. Measure or transmit current, voltage, RS232, RS485, USB, solenoid relay switch and logic switch.
HART® Pressure Transmitters
0-10 Volts Output Pressure Transducers
0-5 Volts Output Pressure Transducers
RS232 Serial Interface Pressure Sensors
RS485 Serial Interface Pressure Sensors
4-20mA Output Hydrostatic Level Transmitters & Sensors
USB Pressure Sensors
I²C Serial Interface Sensors and Instruments
SDI-12 Serial Interface Sensors and Instruments
0-20mA Output Pressure Transmitters
4-20mA Output Pressure Sensors
Ratiometric 0.5-4.5 Volts Output Pressure Transducers
0-10 Volts Output Hydrostatic Sensors, Probes & Transducers
1-5 Volts Output Pressure Transducers
Modbus Communications Protocol Pressure Sensors
HART® Liquid Level Transmitters
Question & Answers
Find answers to questions about analogue and digital measurement signals used to transmit readings from measurement instrumentation.
Analogue vs digital signal usage
Do most sensors have an analogue output?
Yes and no, but typically all sensors start with an analogue signal of some kind , the transducer but normally its too weak a signal to transmit far and is uncompensated for environmental changes. A signal conditioning unit (SCU) compensates and converts the signal to something more universal like RS485, 4-20mA, 0-10Vdc , Modbus, IO-Link, or i2c.
Analogue is still dominant on long cables of say 20-100m, but digital is becoming much more common inside instrumentation and packages, and digital interfaces such as RS485 can be used over much greater distances without data corruption. Sensors on production road vehicles for instance, are becoming all digital, typically use the CANbus digital protocol.
Is 0.5-4.5Vdc output proportional to input supply voltage
Many other companies use “Ratiometric” to describe a pressure transducer with a “0.5 to 4.5 Vdc” output signal. Does it really mean that the output signal is proportional to the input supply and why is it not specified as a sensitivity in mV/V?
mV/V senstivity is used to describe the output of a strain gauge output type device, e.g. 2mV/V, the output is typically much smaller than the input voltage hence the Millivolt to Volts ratio. 0.5 to 4.5 V output is an amplified output where the output is comparable to the input voltage which is typically 5Vdc.
Also on some circuits there is a limitation on the supply voltage e.g. 5V +/-0.5V, and a mV/V description of the output is more suited to describing outputs that can be used with a wide range of supply voltages. However a change in input voltage within those limits of constraint will directly affect the output hence the term “ratiometric”, whereas an input supply that is regulated will maintain a constant output.
Related Guides
- Rangeable
- High Frequency Response
- Supply voltage and load resistance considerations for pressure transmitters
- Pressure Transmitters
- Voltage Output Pressure Transducers
- Millivolt Output Pressure Transducers
- How to get a 10 volt signal from a 4-20mA output pressure sensor
- Intrinsic Safety
- Digital Interface
- Transforming a 2 wire Current Loop into a Voltage Output Signal
- Why use 4-20mA and 3-15 psi rather than 0-20mA & 0-15psi
- What is the difference between zero offset and zero drift?
- Output signal orientation for a negative gauge pressure range
- What is the difference between a pressure transducer and a transmitter
- What can cause random variation in pressure transducer output
- What are the advantages of using Wired Sensors instead of Wireless Sensors
Related Definitions
- 2 Wire
- 3 Wire
- 4 to 20 mA Current Loop Output Signal
- 4 Wire
- Amplified Voltage Output
- BFSG – Bonded Foil Strain Gauge
- Deadband
- FSO – Full Scale Output
- HART®
- mV/V – Millivolts per Volt Output Signal
- NC – Normally Closed
- NO – Normally Open
- Piezoresistive Strain Gauges
- Ratiometric
- Span
- Span Offset
- Span Sensitivity
- Square Root Extraction
- Threshold
- Totalizer
- Transducer
- Transmitter
- TSL – Terminal Straight Line
- TSS – Thermal Span or Sensitivity Shift
- Turndown Ratio
- USB
- Vented Cable
- Wheatstone Bridge Strain Gauge
- Zero Offset
- Zero Tare
Related Tools
- Bit to Measurement Resolution Converter
- Pressure Transducer Millivolt (mV) Output Calculator
- Pressure Transducer 0.5-4.5V Voltage Output Calculator
- Pressure Transducer 1-5V Voltage Output Calculator
- Pressure Transducer 0-5V Voltage Output Calculator
- Pressure Transducer 0-10V Voltage Output Calculator
- Pressure Transmitter 4-20mA Current Output Calculator
- Pressure Transmitter 0-20mA Current Output Calculator
- DP Flow Transmitter Output Calculator
- Load Cell Millivolt (mV) Output Calculator
- Torque Transducer Millivolt (mV) Output Calculator
- Strain Gauge Transducer Millivolt (mV) Output Calculator
- Temperature Transmitter 4-20mA Current Output Calculator
- Flow Transmitter 4-20mA Current Output Calculator
- Liquid Level Transmitter 4-20mA Current Output Calculator
- Measurement Reading to 4-20mA Signal Converter
- Calibration Error Calculator