B&R X20AT4222 X20 Temperature Input Module

Process Automation Overview

The B&R X20AT4222 (X20AT4222) is a high-precision 4-channel resistance temperature measurement input module designed for integration within the modular B&R X20 control environment. Deployed across demanding thermal process industries such as chemical manufacturing, plastics extrusion, and pharmaceutical climate validation, this module interfaces directly with standard RTD sensors to stabilize closed-loop thermal processes. By transmitting precise temperature metrics directly to the centralized controller, the unit eliminates processing jitter and safeguards equipment against thermal overshoots, mitigating expensive material loss and maximizing process availability.

Conversion Architecture and Sensor Interfaces

Equipped with four analog inputs optimized for Pt100 and Pt1000 resistance temperature detectors, the module utilizes a high-efficiency Sigma-delta converter layout with a 16-bit digital resolution. It natively accommodates both 2-wire and 3-wire installation paths, utilizing an integrated constant current supply to compensate for intrinsic line resistance over long cable distances. The system features a configurable hardware filter with adjustable time parameters ranging from 1 ms to 66.7 ms, enabling engineers to tune out high-frequency electrical noise from surrounding plant equipment.

Technical Performance Matrix

Engineering Diagnostics and FAQs

How should the channel settings be adjusted to maintain the fastest conversion time?

When only a single temperature sensor is required, disable the remaining three channels within the Automation Studio hardware tree. This action drops the overall conversion time down to 20 ms using the standard 50 Hz noise filter, optimizing the module's responsiveness for high-speed thermal tracking applications.

What is the practical benefit of using the 3-wire connection over the 2-wire configuration?

The 3-wire connection topology uses a third copper lead to monitor the electrical resistance of the field cabling dynamically. The X20AT4222 subtracts this line resistance calculation from the active measurement circuit, preventing long field cable runs from introducing artificial positive offsets into the final 0.1 deg C temperature calculations.

Can this module process standard linear resistance inputs without converting them to temperature?

Yes. The output format can be configured to supply raw INT or UINT values representing absolute resistance values. This allows the module to interface with linear potentiometers or custom resistance sensors that do not conform to standard Pt100 or Pt1000 curves.

Field Commissioning and Wiring Guidelines

• Terminal Strip Wiring Precision: For 3-wire installations, verify that the two compensation leads are landed on the exact matching terminals specified in the electrical schematic. Keep all terminal connections tightened to specification to eliminate localized contact resistance variances, which can distort the 16-bit Sigma-delta converter calculations.

• Low-Voltage Signal Shielding: Route all RTD signal wiring using twisted-pair, shielded cables. Ground the cable shield exclusively at the control cabinet grounding busbar to prevent ground loops. Keep these sensitive analog sensor runs isolated from high-voltage AC motor wires and switching inductors by a minimum distance of 200 mm.

• Backplane Budget Allocation: Ensure the combined power profile of the module—specifically the 0.01 W bus load and the 1.1 W internal I/O consumption—is fully accounted for in the rack energy calculations. If the total local I/O draw exceeds the limits of the primary bus supply, place an additional X20 potential feed module directly adjacent to this unit.