Digital guide
You are here:
B&R X20AT4222
Product Overview:
The X20AT4222 is a 4-channel analog input module designed for thermocouple signal acquisition. It is part of the B&R X20 I/O system and is engineered for high-precision temperature measurement in industrial automation environments. The module features galvanic channel-to-channel isolation and supports 8 thermocouple types directly.
Detailed content
Supported Thermocouple Types:
J, K, T, E, N, R, S, B
Key Technical Specifications:
| Parameter | Value |
|---|---|
| Number of Channels | 4 |
| Input Type | Thermocouple (TC) |
| Resolution | 16-bit |
| Measurement Range | -200°C to +1800°C (type-dependent) |
| Cold Junction Compensation | Integrated, automatic |
| Sampling Rate | Up to 10 kHz per channel |
| Isolation Voltage | 500 V DC (channel-to-channel) |
| Supply Voltage | 24 V DC (±20%) |
| Power Consumption | ≤ 2.5 W |
| Operating Temperature | -25°C to +70°C |
| Protection Class | IP20 (front), IP65 (with housing) |
| Dimensions (W x H x D) | 90 mm x 120 mm x 74.5 mm |
| Weight | Approximately 220 g |
| Connection | Screw terminal, 2.5 mm² |
| Diagnostics | Overrange, underrange, open circuit detection |
Functional Features:
- Linearization of thermocouple characteristic curves is performed internally in hardware
- Automatic cold junction compensation using an integrated reference junction sensor
- Channel-to-channel galvanic isolation eliminates ground loop interference
- High common-mode rejection ratio (CMRR) ensures noise immunity in electrically noisy environments
- Supports 2-wire, 3-wire, and 4-wire connection modes depending on thermocouple type
Working Principle:
The thermocouple voltage generated at the measuring junction is amplified by a precision instrumentation amplifier. The signal is then converted by a 16-bit A/D converter. The internal microcontroller performs cold junction compensation and linearization using stored polynomial coefficients for each thermocouple type. The processed digital value is transmitted to the PLC via the X20 bus interface.
Material Composition:
- Housing: Glass-fiber reinforced polyamide (PA66-GF30), halogen-free
- Terminals: Tin-plated copper alloy
- PCB: FR-4, conformally coated
Structural Characteristics:
- DIN rail mounting (TS 35, EN 60715)
- Spring-loaded terminal connections for reliable wire clamping
- Status LEDs per channel for diagnostic indication
- Module width: 15 mm (X20 standard)
Advantages & Highlights:
- Direct thermocouple connection without external signal conditioners
- 8 thermocouple types selectable via software — no hardware changes required
- 10 kHz sampling rate enables fast transient temperature capture
- Full diagnostic coverage including open-circuit and short-circuit detection
- Compact X20 form factor saves cabinet space
Applicable Industries:
- Plastics and rubber processing
- Metallurgy and heat treatment
- Food and beverage production
- Pharmaceutical manufacturing
- Power generation and boiler control
- Glass and ceramics industry
Installation Requirements:
- Mount on DIN rail TS 35 (EN 60715)
- Ensure adequate ventilation — maintain minimum 10 mm spacing between modules
- Use shielded thermocouple cables for noise-critical applications
- Connect thermocouple wires with correct polarity
- Ground the shield at the control cabinet side only (single-point grounding)
Usage Precautions:
- Do not exceed the maximum input voltage of ±80 mV (thermocouple range)
- Never disconnect thermocouples under live operating conditions — this triggers open-circuit diagnostic
- Verify thermocouple type selection in the B&R Automation Studio configuration before commissioning
- Do not apply voltage to the input terminals from external sources
- Store and transport at -40°C to +85°C
