This is the Photo of a RTD 3-W Mains Powered Temperature 4-20mA Transmitter. The Circuits and PCB are here
|From Soldermans Basic Electronics|
Now with new Technologies like Zigbee and Modbus, We can classify Transmitters as shown below. The Measured Parameter Temperature, Flow or Events Has to reach an Intelligent Data Storage and Analysis System. It may just be an Human Operator who jots the data on a Notepad and Turns a Few Dials based on his Experience or an embedded controller. It could even be a Computer Network or a Web Application used by many, like Monitoring the Weather Attributes.
- Analog Transmitters – Like 4-20mA Loop.
- Electrically Isolated Analog Transmitters.
- Transmitters that need to be Intrinsically Safe.
- Digital Transmitters and Optical Interface.
- Wireless Transmitters and TCP-IP.
The job of the transmitter is to take the weak analog measured parameter information from sensor, be close to it, amplify, clean, linearize the signal if required and send strong – error free data over a long distance to an operator or system.