did you know that you get a great discount on siemens plc starter kits when you get a realpars pro membership check out the links in the description over the years the terms sensor transducer and transmitter have become confusing because they're often used interchangeably and indiscriminately by different vendors the terms sensor and transducer have been around for a very long time but in the world of process control the term transmitter is not very old in particular the term transducer is tossed around as a name for many devices and instruments if you conduct a web search of the terms sensor and transducer you'll get lots of different definitions many organizations have their own definitions just to confuse the issue sensor and transducer have often been used as synonyms okay let's start with some suitable definitions that we'll use in this video a sensor is a device or element that performs the initial measurement as it senses the changes in a physical variable a sensor is a device that makes physical contact with the variable being measured and detects changes and provides a corresponding output signal that can be measured a transducer is a device that converts one form of energy to another a transducer provides an output quantity having a specified relation to an input quantity in the field of instrumentation the output quantity is an electrical or electronic signal so we say that a transducer measures pressure load force or other states and converts the reading into an electrical or electronic signal for example a strain gage is a transducer whose resistance value changes proportionally to the strain it experiences here's an interesting statement all sensors are transducers but not all transducers are sensors what do we mean by that well consider a loudspeaker that converts an electrical signal into motion the loudspeaker is a transducer but not a sensor alright let's talk about the term transmitter because it has more than one definition the process control term was likely borrowed from the telecommunications world where transmitter is a device that produces and transmits radio waves radiating from an antenna these radio waves are eventually detected and demodulated by a radio receiver the receiver produces sound waves for the human ear in the world of process control a transmitter is a device that transmits a standard instrumentation signal representing a physical variable being measured the standard electrical signals are one to five volts or four to twenty milliamps which represents zero to one hundred percent of the physical variables being measured this transmitted signal is detected by a receiver such as an analog input on a plc or a dcs so we just said that the transmitter signal represents the physical variable how does the transmitter know what the physical variable is that's where a sensor or transducer comes into the picture a sensor performs the initial measurement if necessary a transducer converts this initial measurement into an electrical signal that is then amplified and standardized by the transmitter here's an example we're measuring a process pressure with a range of NUMBER_TOKEN to NUMBER_TOKEN psi our sensor transducer performs the initial measurement and converts it to an electrical signal of zero to three millivolts the transmitter then converts that signal to a standard signal of one to five volts which is received by a plc analog input module many vendors use the terms pressure transmitter and pressure transducer interchangeably but we now know that the two devices are not the same so it's buyer
START_SPONSOR_TOKEN know that you get a great discount on siemens plc starter kits when you get a realpars pro membership check out the links in the description END_SPONSOR_TOKEN