Advances in science and technology from time to time is growing fast, especially in the field of industrial automation. This development was evident in industrial pemabrikan, where previous work using human hands, then switch to using the machine, next to the electro-mechanic (semi-automatic) and now uses robotic (full automatic), such as the use of Flexible Manufacturing Systems (FMS) and Computerized Integrated Manufacture (CIM) and so on.
Any model that is used in the automation system pemabrikan highly dependent on the reliability of the control system used. The results showed any sophisticated control system that is used will depend on the sensor or transducer used. The sensor and transducer is a device or component that has an important role in a system of automatic settings. The accuracy and appropriateness in selecting a sensor will determine the performance of the system settings automatically.
Input quantities in most control systems are not electrical quantities, such as the amount of physical, chemical, mechanical, and so on. To put the amount of electricity to the measuring system, or a system of manipulation or control system, it is usually the amount of electricity that is not first converted into an electrical signal through a device called a transducer. Before going further we learn of sensors and transducers there are a few more tools always complement and accompany the presence of sensors and transducers in a measurement system, or a system of manipulation, and control system that is called the measuring instrument.
Definitions
a) Sensor is a device used to detect symptoms or signals originating from a change of energy such as electric energy, physical energy, chemical energy, biological energy, mechanical energy and so on.
Example; Camera as vision sensors, as sensors hearing ear, the skin as a touch sensor, LDR (light dependent resistance) as a light sensor, and more.
b) The transducer is a device which, when driven by an energy in a transmission system, will channel the energy in the same form or in a different form to the next transmission systems “. Transmission of this energy can be electrical, mechanical, chemical, optical (radiation) or thermal (heat).
Example; generator is a transducer that converts mechanical energy into electrical energy, the motor is a transducer that converts electrical energy into mechanical energy, and so on.
c) measuring instrument is something tool that serves to provide a certain limit value or price of the symptoms or signals originating from a change in energy.
d) Example: voltmeter, ampermeter to electrical signals; tachometer, speedometer for speed mechanical motion, lux-meter for light intensity, and so on.
Other provisions that need to be considered in choosing the right sensor is to ask the following questions:
a. Is quite meet the physical size sensor to be mounted in the necessary place?
b. Is he accurate enough?
c. Does he work on an appropriate range?
d. Whether it will affect the quantity being measured ?.
For example, if a large heat sensor dipped into the water a small amount of water, even cause the water heating effect, not the censor.
e. Does he not easily damaged in use ?.
f. Whether he can adjust to the environment?
g. If the cost is too expensive?