KL3208 by Beckhoff

The KL3208 is an analog input terminal manufactured by Beckhoff for the KL Analog Input Modules series. It captures resistance signals from platinum or nickel RTD sensors and forwards temperature values to a PLC, allowing closed-loop control in industrial automation. Because the terminal aligns on the same DIN rail as other Beckhoff I/O cards, no separate signal converters are needed. Temperature measurement can therefore be placed directly beside digital, motion, or power terminals in a compact node.

Eight differential channels are provided, so up to 8 RTDs can connect through 2-wire links. The default configuration recognizes a PT1000 element, while selectable ranges of 6 k?, 65 k?, or 655 k? accommodate other sensors. Lead and probe resistance may reach 650 k? without clipping, which supports applications with long cable runs. Each conversion step equals 0.01 °C per digit, and this resolution is paired with a full-scale measurement error of ±0.25 °C between -20 °C and +60 °C to support tight process tolerances. The input process image delivers eight data words plus optional status bytes, while an output image can accept eight control bytes for parameter downloads. All conductors use simple 2-wire connections, and spring-cage contacts simplify shield connections in noise-sensitive installations.

Tool-free mounting on a 35 mm DIN rail simplifies installation, and sixteen push-in terminals provide 16 points for sensor attachment and looping. The housing has an IP20 ingress protection rating, so it must be installed inside an enclosure and is protected against accidental finger contact with internal parts. It does not provide protection against water ingress. Temperature acquisition spans -50 °C to +150 °C, covering typical HVAC, machine-tool, and food-processing temperature ranges. Nonoperating storage is permitted from -40 °C to +85 °C. Backplane contacts route K-bus power and data through adjacent terminals, reducing panel wiring and maintaining a uniform I/O architecture.