Allen-Bradley 1734-IT2I Analog Input Module

1734-IT2I Thermocouple Module by Rockwell

Product Introduction

The Allen-Bradley 1734-IT2I belongs to the versatile POINT I/O family from Rockwell Automation. This analog temperature input module specifically handles two differential, individually-isolated thermocouple inputs. Therefore, it delivers accurate readings even in electrically noisy environments. Furthermore, its Delta Sigma conversion type ensures high-precision data with a resolution of 15 bits at 2.5 µV/cnt.

This 1734-IT2I module supports signed integer data formats across four temperature scales: Celsius, Fahrenheit, Kelvin, and Rankine. Additionally, a custom 1 mV scale is available for specialized applications. For instance, you can configure alarms for under-range, over-range, cold junction compensation (CJC) open-wire detection, and four distinct level thresholds (low-low, low, high, high-high). Meanwhile, the module produces eight bytes of scanner data and fault status without consuming extra I/O scanner Tx resources. Consequently, system efficiency remains high.

Key Technical Specifications

The 1734-IT2I operates with an input voltage range of ±75 mV and a voltage rating of 24 Volts DC. Its POINTBus current draw is 175 mA at 5 Volts DC. Moreover, the module features a high impedance of 100 kΩ and a resistance of 1 MΩ, which minimizes signal loading on the thermocouple. Specifically, its continuous isolation voltage is 50 Volts, ensuring safe separation between channels and the backplane.

Power dissipation is rated at 1 Watt maximum, translating to a thermal dissipation of 3.3 BTU/hour. This low heat output makes the 1734-IT2I suitable for dense I/O installations. Notably, no external DC power supply is necessary, as the module derives its power directly from the POINTBus. However, you must install it exclusively on the 1734-TBCJC wiring base assembly, which provides the required cold junction compensation reference.

Mechanical and Environmental Ratings

This module measures just 2.21 x 0.47 x 2.97 inches (56.1 x 11.9 x 75.4 mm) and weighs only 0.08 pounds (0.036 kilograms). Its open-style enclosure suits panel mounting in controlled environments. The operating temperature range spans -20 to 55 °C, while storage temperatures can extend from -4 to 85 °C. Furthermore, the 1734-IT2I withstands non-condensing relative humidity from 5% to 95%.

For vibration resistance, it handles 5 g at 10 to 500 Hz. Operating shock tolerance is 30 g, and non-operating shock reaches 50 g. These rugged specifications confirm that the 1734-IT2I performs reliably in demanding factory-floor conditions. Meanwhile, four real-time status indicators—network, module, input 0, and input 1—enable quick diagnostics and troubleshooting.

Installation Guidelines

Installing the 1734-IT2I is straightforward. First, mount the module onto the 1734-TBCJC wiring base assembly. Next, snap it securely into the DIN-rail mounted POINT I/O system. After that, connect your thermocouple sensors to the designated terminals on the base. Remember to verify that the key switch position is set to 6, matching the module type. Finally, apply 24V DC power through the POINTBus; no additional power wiring is required.

Proper cold junction compensation depends on the 1734-TBCJC base. Therefore, ensure the base is correctly positioned and not subjected to rapid temperature changes near the CJC sensor. Additionally, use shielded thermocouple extension wires for optimal noise immunity. For best practices, consult the module's user manual for detailed wiring diagrams and configuration steps via your Rockwell automation controller.

Packaging and Shipping

Each Allen-Bradley 1734-IT2I unit ships individually in anti-static packaging to prevent electrostatic discharge damage. The package includes the module only. Accordingly, the 1734-TBCJC wiring base and any mounting hardware must be ordered separately. We ship all orders via trusted carriers: FedEx, UPS, or DHL, ensuring fast and trackable delivery worldwide.

Frequently Asked Questions (FAQ)

1. Can the 1734-IT2I accept both J and K type thermocouples?
Yes, the 1734-IT2I supports all standard thermocouple types (J, K, T, E, R, S, B, N) because its universal input circuit accommodates the ±75 mV range.

2. Do I need an external power supply for this module?
No, the 1734-IT2I draws its operating power directly from the POINTBus at 5V DC, requiring no external 24V DC supply.

3. What causes the CJC open-wire alarm on the 1734-IT2I?
This alarm triggers when the module detects a broken or disconnected thermocouple wire. It also monitors the cold junction compensation sensor for faults.

4. How many bytes of input data does the 1734-IT2I consume?
The 1734-IT2I generates eight bytes of scanner Rx data for temperature values and status, but it does not use any scanner Tx I/O data.

5. Is the 1734-IT2I compatible with other POINT I/O bases?
No, it requires the dedicated 1734-TBCJC wiring base assembly, which provides the necessary cold junction reference for accurate thermocouple measurements.