The electronics of the infrared camera or the thermometer converts the object temperature calculated on the basis of the output signal of the detector into a linear 0/4 - 20mA current signal or a 0 - 10V voltage signal. These standardized analog signals allow easy connection to regulation systems for process control. Most of the measuring instruments used today also have digital interfaces (e.g. USB, RS485, Ethernet, Profibus) for data output and for accessing device parameters due to the digital measured value processing. An advantage of the infrared measuring devices with digital interface is the possibility of field calibration with the aid of available calibration software from the device manufacturer, so that, for example, only the relevant sensor parameters (emissivity, etc.) need to be adapted when changing the product on a production line.
Some common interfaces are:
The linear 0/4 - 20 mA current signal is directly proportional to the object temperature determined by the infrared temperature measurement device.
The linear 0 - 10 V voltage signal is directly proportional to the object temperature determined by the infrared temperature measurement device.
Thermocouple interfaces (type K, type J):
The signal output is analogous to type K and J thermocouples as a voltage signal. The output voltage is proportional to the measured temperature. Through the same interface, contact and non-contact temperature measurement can be combined or existing thermocouples can be replaced with modern infrared thermometers.
Bus interfaces (CAN, Profibus DP):
Bus interfaces are interfaces for bilateral signal transmission between transmitter and receiver via a signal line and are considered digital interfaces. They allow bidirectional communication between the sensor and the control system. The interfaces CAN and Profibus DP formally belong to the group of fieldbus systems.
Other digital interfaces such as the RS232 and RS485 serial interfaces, as well as Ethernet and USB, permit high-speed two-way signal transmission.