Product Description:

The KL3222 is an analog input terminal manufactured by Beckhoff and belongs to the KL Analog Input Modules series. It accepts resistance temperature detector signals and converts them to digital words that the programmable controller reads through the K-Bus backplane. By supplying precise temperature feedback, the module lets a control system adjust heaters, coolers, or safety interlocks in production machinery without adding standalone signal conditioners.

Each channel uses 4-wire sensing, so the module compensates for lead resistance and delivers a full-scale reading at the terminals. The internal converter works at a 16-bit digital resolution, giving 65,536 discrete steps across the measuring range and reducing quantization error. At 40 °C ambient and with a Pt100 sensor connected in four-wire mode at 50 Hz, the module’s systematic deviation is limited to 0.1 °C. The temperature value delivered to the controller advances in increments of 0.01 °C per digit, which supports tight proportional-integral loops. The terminal has 2 analog inputs, and their samples appear in the input process image as two data words followed by two status bytes that report sensor faults such as an open circuit. An output process image consisting of two control bytes lets the PLC reset error flags or start diagnostics.

For field distribution enclosures, the terminal draws logic power from the K-Bus while its power contacts can carry up to 10 A to downstream modules, simplifying current distribution. It snaps onto a 35 mm DIN rail and rises only 100 mm in height, making it suitable for shallow panels. The front housing measures just 12 mm wide and uses spring-loaded terminals for quick sensor exchange without tools. With a protection rating of IP20, the unit is intended for cabinets where contact with live parts is prevented, yet no additional sealing against dust or water is required.