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WHAT IS A TRANSMITTER?

Any transmitter is the first step to detect changes in a process and to direct that process. If we want to use these changes in an electronic environment, it is necessary to put them in a certain form. This is exactly where the transmitter comes into play, it gives the electrical equivalent of the detected value. For example, we have a temperature ranging between 0 -1000C, we have a sensor (pt100, thermo couple etc.) that detects this change. As the temperature changes, the data (resistance) from the sensor will also change, the task of the transmitter is to convert this change to certain standards. If we calculate the transmitter adjusted according to the temperature ranging between 0-1000C according to the 4-20mA output, which is one of the industrial standards;

  • à for 500C
  • 20mA – 4mA = 16mA
  • 16mA * [500C * (1/(1000C-00C))] = 8mA

BUT WE’RE NOT DONE HERE,

  • Since the base of 4-20mA is 4mA;
  • We get a linear signal response as 4mA + 8mA = 12mA.

If we were to calculate this example according to another industrial standard, 0-10V, we would see that the signal corresponding to 500C would be 5V.

The choice of transmitter varies according to many conditions such as sensitivity, accuracy, measurement scale, sensor, signal output and external environment. Again, to give an example, in a natural gas pipeline where pressure measurement is made, the pressure transmitter is expected to be ex-proof, that is, a structure that will not cause an explosion.