Allen-Bradley 1756-IRT8I ControlLogix 8-Point RTD/Thermocouple Input | Replacement, Equivalent & Selection Guide
The Allen-Bradley 1756-IRT8I is a ControlLogix platform analog input module designed for precision temperature measurement via RTD and thermocouple sensors. This page provides full technical specifications, compatible replacement models, system compatibility data, and a structured selection guide to help engineers and procurement teams make confident sourcing decisions.
Technical Specifications
- Part Number: 1756-IRT8I
- Brand: Allen-Bradley (Rockwell Automation)
- Series: ControlLogix 1756
- Input Channels: 8 (individually isolated)
- Input Types: RTD (Pt, Ni, Cu) and Thermocouple (J, K, T, E, R, S, B, N)
- Isolation: Channel-to-channel and channel-to-backplane isolated
- Resolution: 16-bit
- Accuracy: ±0.1°C typical (RTD); ±0.5°C typical (thermocouple)
- Operating Temperature: 0°C to 60°C
- Backplane Current: 250 mA @ 5 VDC; 3 mA @ 24 VDC
- Module Keying: Electronic and mechanical
- Dimensions: Standard 1756 single-slot form factor
- Weight: Approx. 350 g
- Certifications: UL, CE, CSA, ATEX (Zone 2)
Compatible Replacement & Equivalent Models
When the 1756-IRT8I is unavailable or end-of-life, the following models are commonly evaluated as replacements. Always verify firmware, wiring, and software compatibility before substitution.
- 1756-IRT8I Series B — Direct series upgrade; backward-compatible wiring and configuration
- 1756-IR6I — 6-channel RTD-only variant; suitable when thermocouple inputs are not required
- 1756-IT6I / 1756-IT6I2 — 6-channel thermocouple-only input; use when RTD inputs are not needed
- FLEX 5000 FXRT8I — Next-generation Rockwell platform; requires Studio 5000 v32+ and updated I/O tree
- Siemens 6ES7331-7PF11-0AB0 — Cross-brand equivalent for S7-300 systems; not pin-compatible, requires rewiring
- Beckhoff EL3204 — EtherCAT RTD module; suitable for distributed I/O architectures migrating away from ControlLogix
Note: Cross-brand replacements require full engineering review. Konmask recommends original Rockwell parts for warranty-critical and safety-rated applications.
Why Choose the Original Model
- Guaranteed Compatibility: Native integration with ControlLogix backplane, RSLogix 5000, and Studio 5000 without add-on profiles or workarounds
- Channel Isolation: Individual channel isolation eliminates ground loop interference — critical in multi-sensor industrial environments
- Dual Sensor Support: Single module handles both RTD and thermocouple types, reducing slot count and BOM complexity
- Proven Field Reliability: Widely deployed in oil & gas, food processing, and pharmaceutical temperature control loops
- Rockwell Support Ecosystem: Full access to firmware updates, TechConnect support, and certified spare parts programs
Typical Applications
- Furnace and kiln temperature monitoring (steel, ceramics, glass)
- Pharmaceutical batch reactor temperature control (FDA 21 CFR Part 11 environments)
- Food and beverage pasteurization and CIP process loops
- Oil & gas pipeline and separator temperature measurement
- HVAC and building automation systems with precision zone control
- Chemical plant heat exchanger monitoring
- Plastics extrusion barrel temperature profiling
System Compatibility
- Compatible Chassis: All 1756 ControlLogix chassis (4, 7, 10, 13, 17-slot)
- Compatible Controllers: 1756-L6x, 1756-L7x, 1756-L8x series (all firmware revisions)
- Software: RSLogix 5000 v16+, Studio 5000 Logix Designer v21+
- Communication: Operates over ControlLogix backplane; compatible with EtherNet/IP, ControlNet, and DeviceNet bridge configurations
- Power Supply: Requires 1756-Pxx series power supply; no external field power required for RTD/TC inputs
- Redundancy: Supported in redundant controller configurations with 1756-RM2/A
Selection Guide
Use the following criteria to determine whether the 1756-IRT8I is the correct module for your application:
- Sensor Type: Required if your loop uses both RTD and thermocouple sensors on the same controller rack
- Channel Count: 8 isolated channels — specify 1756-IR6I or 1756-IT6I if fewer channels suffice
- Isolation Requirement: Mandatory for applications with ground potential differences between sensor locations
- Accuracy Class: Select 1756-IRT8I for ±0.1°C RTD accuracy; for lower-cost, non-isolated alternatives consider 1756-IR6I
- Slot Budget: Single-slot module — verify chassis slot availability before ordering
- Hazardous Area: ATEX Zone 2 rated; for Zone 1/0 applications, add certified Zener barriers or galvanic isolators in the field wiring
- Platform Migration: If migrating to Logix 5000 v32+, evaluate FLEX 5000 FXRT8I as a forward-compatible alternative
Quality Assurance & Sourcing
- Authenticity: All 1756-IRT8I units sourced by Konmask are verified against Rockwell Automation serialization records
- Inspection: Each unit undergoes visual inspection, firmware version verification, and functional power-on test prior to shipment
- Condition Options: New-in-box (NIB), factory-reconditioned, and tested-used grades available — clearly labeled on each listing
- Packaging: Anti-static ESD packaging with original or equivalent protective foam insert
- Warranty: 12-month replacement warranty on all grades; NIB units carry full Rockwell factory warranty where applicable
- Traceability: Batch and serial number records maintained for all shipments
How to Order
- Step 1: Confirm part number: 1756-IRT8I (specify Series A or B if required)
- Step 2: Select condition grade: New / Reconditioned / Tested-Used
- Step 3: Add to cart or contact Konmask for volume pricing and lead time confirmation
- Step 4: Provide shipping address — DHL, FedEx, and sea freight options available for international orders
- Step 5: Receive order confirmation with serial number and inspection report within 24 hours of payment
For urgent requirements or bulk orders (>5 units), contact us directly at support@konmask.com or +0086 19859288691.
Replacement & Compatibility FAQ
Q: Can the 1756-IRT8I replace the 1756-IR6I directly?
A: Not slot-for-slot. The IRT8I has 8 channels vs. 6 on the IR6I, and supports both RTD and thermocouple inputs. You will need to update the I/O configuration in Studio 5000 and remap tags accordingly.
Q: Is the 1756-IRT8I compatible with GuardLogix controllers?
A: Yes, it can be used in a GuardLogix system for standard (non-safety) temperature monitoring loops. It is not a SIL-rated safety module.
Q: What is the difference between Series A and Series B?
A: Series B introduced improved cold junction compensation accuracy and enhanced EMC performance. Both are electrically and mechanically interchangeable in the same chassis slot.
Q: Can I mix RTD and thermocouple sensors on the same 1756-IRT8I module?
A: Yes. Each of the 8 channels is independently configurable for RTD or thermocouple type via Studio 5000 — no hardware changes required.
Q: Does Konmask provide a test report with the module?
A: Yes. All units ship with a functional test report confirming power-on status, firmware revision, and channel continuity check results.
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Original Source: https://Konmask.com
Contact: support@konmask.com | +0086 19859288691
