Sensor transmitters generate energy outputs from sensors and transducers. These outputs produced by sensor transmitters include current loops, variable voltage levels, timers, relays, and frequency or pulse signals. A sensor transmitter operates upon receiving signal or other data communication from three types of inputs, such as inputs from special devices, signal inputs and sensor inputs. Examples of special inputs for sensor transmitters include timers, clocks, encoders and counters. AC current, AC voltage, DC current and DC voltage make up the group of signal inputs. Sensor transmitters also connect with strain gauges, resistance temperature detectors, accelerometers, thermocouples and thermistors.

User interface, form factor and mounting style are some of the factors to consider when buying sensor transmitters. As for model or form, sensor transmitters are either integrated circuit chips or printed circuit boards that plug into larger computer circuit boards. A sensor transmitter can be mounted on rack, panels or chassis. Stand-alone sensor transmitters are also available and come as bench top or as a floor unit with a cabinet.

1. Buy sensor transmitters from certified manufacturers or brand distributors.

2. Get sensor transmitters with special features or specifications.

3. Make sure sensor transmitters have warranties that can reduce repair costs.

Action Steps
The best contacts and resources to help you get it done

Buy from certified sensor transmitter distributors or manufacturers

Sensor transmitters that are ISO-, CSA- or UL-certified can guarantee you a quality product.

I recommend: Pics distributes sensor transmitters and other types of transmitters that are CSA or UL certified. Devar also carries UL- and CSA-approved sensor transmitters and other signal equipment.

Look for sensor transmitters with certain specifications or features

Some manufacturers produce sensor transmitters that operate or store in specific temperatures.

I recommend: Minco features relative humidity sensor transmitters that work through digital signal processing. Their stainless steel construction resists damage from chemicals, condensation or other pollutants. Laurel Electronics manufactures sensor transmitters and other instruments with operating temperatures ranging from 32 to 158 degrees F. The devices can be stored at temperatures ranging from -40 degrees to 185 degrees F.

Ensure that sensor transmitters that are warranted

Sensor transmitters are available with service warranties in case defects or repairs are needed.

I recommend: Dwyer Instruments offers a one-year warranty for service or parts replacement. Automation Products Group products, including sensor transmitters, have 18-month warranties.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  To send electronic or computer signals over long distances, try sensor transmitters with current loops. They also rely on feedback to transmit current even through interference or noise. A sensor transmitter that provides frequency outputs uses amplitude modulation, or AM, or frequency modulation, or FM. Pulse trains and sine waves are also sometimes used as sensor transmitter outputs.
• •  Choose from sensor transmitters that feature a variety of user interface options. Most sensor transmitters have a computer programmable function, a touch screen, and a front panel and display. Sensor transmitters can also be manufactured as handheld devices that require programming from a remote host computer or other facility.