RTD PT100 Mains Powered Transmitter

This is a RTD Pt-100 Transmitter, It can Convert Thermocouple mV or RTD mV to 4-20 mA Current Transmitter. The part numbers on Circuit and silk screen may not match. But the PCB may be usable. The output is a current source and not a current sink. It goes to a 4-20mA Mux with a common ground.

This low-cost transmitter was made to send RTD information in a 4-20mA over long distance. The 4-20mA was the input to a Analog-Mux which interfaced to a GE-Fanuc PLC system and a 486 Computer. The Analog Multiplexer Built around CD4051 was was controlled by PLC to get data from numerous channels. This reduced the cost of the System. This is ok when Real-Time Acquisition is not required. The Analog 4-20 to 4-20 Mux-Buffer circuit can also be seen at Industrial Process Control Circuits.

This was done as customer budget could not afford dedicated analog input modules for every channel. There were more than 50 Inputs. The thermal inertia of system did not need a real time or fast correction.

The PNGs of PCB is 600dpi 16 color. It is to be scaled appropriately.

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.

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.

RTD 3-W Mains Powered Temperature 4-20mA Transmitter.

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• Temperature Transmitters - Yokogawa