Allen-Bradley 1734-IR2 POINT I/O 2-Channel RTD Input Module

RTD temperature measurement on the POINT I/O rail

The Allen-Bradley 1734-IR2 reads two resistance temperature detectors or raw resistance values directly on a POINT I/O node, so a remote skid can measure bearing, process or ambient temperature without a separate transmitter. It supports 100 and 200 ohm platinum RTDs in both the European 0.00385 and the American 0.003916 curves, 10 ohm copper and several nickel types, and its 16-bit converter resolves 0.03 °C per count on a Pt 385 sensor at 25 °C.

The module draws all of its power from the POINTBus, up to 220 mA at 5 V DC, and needs no external field supply. Notch filters from 50 Hz to 480 Hz let you set the update time from 40 ms down to 4 ms per module.

Technical specifications

RTD wiring and configuration

Fit the module on a 1734-TB, 1734-TBS, 1734-TOP or 1734-TOPS base with the keyswitch at position 6. Rockwell recommends shielded copper wire of 0.25 to 2.5 square millimetres. Because the inputs have no overvoltage protection, keep sensor wiring away from power cables and do not connect powered signals to the input terminals.

Choose the sensor type and the notch filter in the controller configuration. The 50 Hz and 60 Hz notches give the best mains-noise rejection; the higher notches speed up the response where noise is not an issue. Status indicators on the module show module, network and per-channel state, with a flashing red channel indicator meaning the reading is at the end of its range.

1734-IR2, 1734-IR2E and 1734-IT2I

The 1734-IR2E in the same document uses a narrower 78.12 to 234.38 ohm range for finer resolution, 0.006 °C per count, on 100 ohm platinum RTDs from -50 to +325 °C. For thermocouples Rockwell offers the isolated 1734-IT2I, which needs the 1734-TBCJC base for cold-junction compensation. Order the version that matches the sensor in your plant; the modules are not interchangeable.

Documents and quotation

The Rockwell Automation installation instructions for the 1734-IR2, 1734-IR2E and 1734-IT2I modules are attached and carry the sensor tables and specifications used here. Related items in our PLC and I/O cards catalogue include the 1734-AENTR POINT I/O adapter. Confirm the exact catalog number, series letter and firmware or hardware revision on the product label, and the compatibility with your existing system, before ordering. Seven Star LLC supplies against the full catalog number, and stock and lead time are confirmed at quotation.

How the 1734-IR2 Works

An RTD is a resistor whose value rises with temperature in a known way. The 1734-IR2 passes a small excitation current through the sensor, measures the resulting voltage with a delta-sigma converter and calculates the resistance. Using the curve for the configured sensor type, it then converts the resistance into a temperature value, or reports the raw resistance when the ohms range is selected. Three-wire connection allows the module to compensate for the resistance of the lead wires, which matters on long cable runs because every ohm of lead resistance would otherwise appear as a temperature error.

The notch filter decides how long each measurement is integrated. The 50 Hz and 60 Hz notches reject mains-frequency pickup, which is usually the most important consideration for temperature signals that change slowly; faster notches are available where response time matters more than noise rejection.

1734-IR2 Selection & Ordering Guide

• Sensor type: confirm the RTD element (platinum, copper or nickel), its nominal resistance and its alpha coefficient, and check that it appears in the sensor table above.
• Resolution: choose the 1734-IR2E for finer resolution on 100 ohm platinum sensors over a narrower range; use the 1734-IR2 for wider ranges and other sensor types.
• Thermocouples: thermocouple sensors need the 1734-IT2I and its cold-junction base instead.
• Base and keying: order a 1734-TB, 1734-TBS, 1734-TOP or 1734-TOPS base if needed, with the keyswitch set to position 6.
• Power budget: the module draws 220 mA from POINTBus, so check the adapter or expansion supply current when several analog modules share a node.

Quote the series letter and adapter type when you request a quote for the 1734-IR2. Our team can help confirm the correct ordering code.

Installation & Maintenance

Use shielded cable for RTD wiring, ground the shield at one end, and keep the lead wires of each sensor the same length and gauge so lead compensation is accurate. Do not route sensor cables alongside power or drive cables. During maintenance, check the channel status indicators and bits, compare readings against a reference thermometer or a decade resistance box, and inspect terminations for corrosion, particularly in humid or coastal sites.

Typical Applications in Oman & the GCC

• Bearing and winding temperatures on pumps, compressors and motors in oil and gas and water facilities.
• Process temperatures on chemical dosing, heat exchanger and utility skids.
• Chilled-water supply and return temperatures in district cooling plants.
• Food and beverage process temperatures on distributed POINT I/O nodes.

Why Source the 1734-IR2 from Seven Star LLC

Seven Star LLC supplies Allen-Bradley POINT I/O modules, including the 1734-IR2, across Oman and the GCC. Request a quote with the catalog number and quantity.