Product Description:

The X20AI2438 is a two-channel analog input module manufactured by B&R Automation as part of the X20 Fieldbus Input Output Modules series. It plugs onto an X20 backplane and digitizes differential signals from process transmitters, forwarding the numerical values to the controller over the system bus. By isolating the sensor side from the logic domain, the module enables reliable acquisition of pressure, level, and temperature variables in distributed industrial automation architectures.

The conversion path is based on a sigma-delta architecture that delivers a 16-bit code width, giving an LSB size suited to fine process control. Common-mode disturbances between the pair of inputs are rejected by 80 dB, so long cable runs do not corrupt the reading. A hardware filter rolls off at 100 Hz, ensuring that line noise outside the usable band is attenuated before sampling. Across the specified range, the integral nonlinearity remains below 0.003 %, supporting accurate calibration. For safety, the analog domain is galvanically separated from the backplane by a 1000 VAC test voltage. The module presents only 0.05 W of bus power load, while its internal signal conditioning requires 1.15 W, keeping cabinet thermal rise low. Two differential channels are available, allowing independent measurements without shared return currents.

Integrated HART support allows digital diagnostics to ride on the analog lines at 1200 bit/s, with frequency-shift tones of 1200 Hz/2200 Hz recognized by the converter. Each channel supplies up to 0.75 W of regulated excitation at 25 V ±2%, and the circuit can source as much as 30 mA before current limiting engages. The module’s protection category is IP20, indicating finger-safe, ventilated housing that must be installed inside an enclosure. Differential inputs accept sensor signals referenced only to their own pairs, which improves noise immunity when field devices are several meters from the cabinet.