KL3314-0012 by Beckhoff

The KL3314-0012 analog input terminal is manufactured by Beckhoff and belongs to the KL Analog Input Modules series. It is designed to collect low-level electrical measurements from field sensors and present them to a higher-level controller on the same I/O node. By adding this module to a bus terminal stack, machine builders can integrate precision voltage or millivolt readings into PLC-based automation routines while maintaining compact DIN-rail installation.

The module offers 4 input channels, each wired through a 2-wire connection that carries both the signal and its common reference. The four channels provide a combined word length of 4 x 16 bits, so the controller receives 16-bit data from each sensor. Measurement accuracy is specified at < ±0.5% FS, indicating that the worst-case deviation over the full scale stays within half a percent. Temperature measurements have a resolution of 0.1 °C per digit, allowing small changes to be detected when thermocouples or similar sources are attached. Open-circuit detection is built in, so the application can identify a broken sensor lead without extra wiring. The terminal supports a variable installation position, providing flexibility in confined control cabinets. Its circuitry also supports millivolt measurements from low-level instrumentation signals.

During cyclic operation, the bus coupler transmits 8 bytes of process data representing the four channels, while an optional status stream of four 8-bit words can be enabled for detailed diagnostics. A first-order notch filter at 25 Hz is implemented in the conversion path to suppress line noise. The programmable digital filter has a default coefficient of 0x0000, allowing its settling behavior to be adjusted through the fieldbus. The terminal has an IP20 protection rating, so it must be mounted in an enclosure. Its slim housing and variable orientation leave space for neighboring terminals within the I/O assembly.