Allen-Bradley 1734-IE8C POINT I/O 8-Channel High-Density Current Input Module

Eight current channels for dense instrumentation nodes

The Allen-Bradley 1734-IE8C brings eight 4 to 20 mA or 0 to 20 mA analog inputs into a single POINT I/O slot. It is the highest-density current input in this family, meant for remote I/O panels where space on the rail and the number of terminals are limited, for example skid packages that collect many transmitter signals.

The module uses the same delta-sigma converter and 16-bit resolution as the four-channel 1734-IE4C, with the same 0.32 microamps per count and 0.1% accuracy at 25 °C, but the scan of all eight channels takes longer.

Technical specifications

Scan time and channel response

With eight channels, the per-module update time at the default 60 Hz notch is 400 ms; at the 50 Hz notch it is 480 ms, and at the 480 Hz notch it falls to 50 ms. A single channel responds to a step in 50 ms at the default notch and 6.25 ms at 480 Hz.

Select the notch according to the dominant noise. If you need a fast scan on a few loops, the four-channel module is the better fit, because both its update time and the fastest setting are shorter. The input impedance is 60 ohm.

Wiring, power and keying

The module draws 30 mA from a 10 to 28.8V DC Class 2 field supply and up to 75 mA from POINTBus, with power dissipation of 0.6 W at 28.8V DC. It mounts on the 1734-TB, 1734-TBS, 1734-TOP or 1734-TOPS bases, keyswitch position 3, and weighs 36 g.

Use shielded copper wire, 22 to 14 AWG rated at 100 °C or higher. Wiring category is 2 on signal ports and 1 on power ports. The isolation is 50V, tested at 1500V AC for 60 s between the field side and the system; there is no isolation between inputs or between inputs and field power. This matters when several transmitters share a common loop supply. Where a ground loop is suspected, fit an isolator on the affected channel rather than changing the field power arrangement of the whole node.

Documents and quotation

The sheet 1734-IN033 gives the input data, notch tables and certification information. Please send the 1734-IE8C reference, quantity, adapter or controller and the transmitter list when asking for a quotation. Related hardware appears under PLC & I/O Cards.

How the 1734-IE8C Works

Each channel of the 1734-IE8C passes the loop current through a low-value precision resistor, and the delta-sigma converter measures the resulting voltage. A delta-sigma converter samples the signal many times and averages it through a digital filter; the selectable notch frequency sets where this filter rejects noise most strongly. Choosing the notch that matches the local mains frequency gives the best rejection of hum picked up on long cable runs. The module then scales the result and sends it to the controller over POINTBus and the network adapter.

The 4–20 mA range has a live zero: a healthy transmitter never sends less than 4 mA, so a reading well below 4 mA points to a broken wire, a failed transmitter or a missing loop supply. This makes it straightforward to separate a real low process value from a wiring fault in the controller logic.

Selection & Ordering Guide for the 1734-IE8C

• 1734-IE8C – eight current inputs, 0–20 mA or 4–20 mA.
• 1734-IE8CK – conformal-coated version for harsh atmospheres.
• 1734-IE4C – four current inputs with a faster module scan.
• 1734-IE2C – two current inputs for small nodes.
• 1734-IE2V – two voltage inputs for 0–10 V or ±10 V signals.

Every POINT I/O node also needs a terminal base for each module and an adapter (for example the 1734-AENT for EtherNet/IP). With eight channels in one module, check that the 1734-TB or TOP base wiring layout suits the number of field terminals you need. Our team can help confirm the correct ordering code when you request a quote.

Installation & Maintenance of the 1734-IE8C

• Set the terminal base keyswitch to position 3 before fitting the module, so that a module of the wrong type cannot be inserted.
• In Oman and most of the GCC the mains frequency is 50 Hz, so the 50 Hz notch normally gives the best noise rejection; in Saudi Arabia the grid is 60 Hz.
• Ground cable shields at one end only and follow Rockwell’s wiring and grounding guidelines, publication 1770-4.1.
• POINT I/O supports removal and insertion under power, but only do this when the area is known to be non-hazardous.
• Verify each loop at commissioning with a loop calibrator at 4, 12 and 20 mA, and record the values for later comparison.

Typical Applications in Oman & the GCC

The eight-channel density of the 1734-IE8C suits remote instrument panels that collect many transmitters in one place: pressure, level and flow on desalination trains, tank farm level monitoring, compressor and pump skids in oil and gas facilities, and chilled-water plants in district cooling systems. Packing eight loops into a 12 mm slot keeps the remote I/O enclosure small, which helps in hot outdoor locations where panel space and cooling are limited.

Why Source from Seven Star LLC

Seven Star LLC is an independent supplier in Muscat. Seven Star LLC supplies Allen-Bradley POINT I/O and related automation components across Oman and the GCC. Send the 1734-IE8C catalog number, quantity and node details and request a quote; our team can help confirm the correct ordering code, terminal base and adapter.