- AC Drives
- Industrial Communications
- PLC & I/O Cards
- Vibration Monitoring
- Automation Accessories
- Controllers & Data Acquisition
- Safety Switches & Guard Locking
- CCTV & Security
- Encoders
- Industrial Computers
- HMI Displays
- Motor Soft Starters
- Isolator & Barrier
- Pneumatic Cylinders
- Servo Drives
- Automation Software
- Robotics
- Machine Vision
Brand: Allen-Bradley
Allen-Bradley 1756-IF8I ControlLogix Isolated Analog Input
Description
Eight channel-isolated analog inputs, 24-bit resolution
The Allen-Bradley 1756-IF8I is an eight-channel analog input module in which every channel is isolated from the others and from the backplane. Each channel can be set to voltage mode (plus or minus 10 V, 0 to 10 V or 0 to 5 V) or current mode (0 to 20 mA), including a sourcing current mode where the channel itself supplies loop power.
Channel isolation removes ground-loop errors that appear when transmitters in different plant areas share a common return, which is a frequent cause of drifting readings on large water and gas sites. Resolution is 24 bits with 0.05 percent calibrated accuracy.
Technical specifications
| Parameter | Specification |
|---|---|
| Catalog number | 1756-IF8I (1756-IF8IK conformal coated listed separately) |
| Inputs | 8 isolated channels, any combination of voltage or current |
| Voltage ranges | +/-10 V, 0-10 V, 0-5 V (resolution 1.49 uV per count) |
| Current range | 0-20 mA (2.99 nA per count); 4-20 mA via scaling |
| Resolution | 24-bit |
| Input impedance | Voltage: 1 GOhm powered, 7500 Ohm unpowered; current: 125 Ohm |
| Sourcing current mode | 20 V DC min to 36 V DC open circuit, current limited under 45 mA |
| Overvoltage protection, max | +/-30 V DC |
| Noise rejection | Normal mode 80 dB at 60 Hz; common mode 120 dB at 50/60 Hz |
| Accuracy | 0.05 percent at 25 C; module error 0.1 percent over temperature |
| Module input scan time, min | 1 ms |
| Open-circuit detection time | 5 s |
| Backplane current | 200 mA at 5.1 V DC; 150 mA at 24 V DC (non-sourcing) or 400 mA (sourcing) |
| Power dissipation | 4.6 W voltage mode; 5.1 W current non-sourcing; 7.3 W sourcing |
| Isolation | 250 V continuous reinforced, input to backplane (3000 V AC type test); 250 V basic, input to input (1500 V AC type test) |
| Data format / conversion | IEEE 32-bit floating point; sigma-delta |
| Features | Onboard data alarming, scaling to engineering units, real-time channel sampling |
| Operating temperature | 0 to +60 C |
| Non-operating temperature | -40 to +85 C |
| Vibration / shock | 2 g at 10-500 Hz / 30 g operating, 50 g non-operating |
| Slot width / keying | 1 slot; electronic keying, software configurable |
| Enclosure / wire category | Open-style; wire category 1 |
Sourcing mode and heat
In sourcing current mode the module powers a two-wire transmitter loop directly from the channel, which saves an external supply but raises backplane draw to 400 mA on the 24 V rail and dissipation to 7.3 W. A chassis with several IF8I cards in sourcing mode needs a power budget check and good ventilation. In non-sourcing mode the draw falls to 150 mA.
Selection notes
Take the IF8I where isolation per channel and high resolution matter, and the 1756-IF8H where HART is required. Settling time and bandwidth depend on the notch filter set in the module configuration, and the values are listed in user manual 1756-UM540. Confirm series, K suffix and terminal block with the manufacturer data before ordering.
Documents and quotation
The linked Rockwell Automation technical data covers the full 1756 I/O range (file size about 15 MB, hosted by Rockwell Automation). Related PLC hardware sits in the PLC & I/O Cards category. For a quotation send the catalog number and quantity to Seven Star LLC, an independent supplier in Muscat.
Datasheets & Documents
- Technical data Rockwell Automation 1756 ControlLogix I/O Specifications, publication 1756-TD002U (September 2026) Download
Reviews (0)
About brand
Allen-Bradley is the brand of Rockwell Automation for industrial control: ControlLogix and CompactLogix controllers, I/O systems, PanelView operator terminals, PowerFlex drives, motor control and industrial network equipment. The company began in Milwaukee in 1903, when Lynde Bradley and Dr. Stanton Allen formed the Compression Rheostat Company to make the motor speed controller Bradley had invented in 1901. It took the name Allen-Bradley in 1909 and was bought by Rockwell International in 1985. Since 2001 its owner has been Rockwell Automation, which is still headquartered in Milwaukee, Wisconsin.
Allen-Bradley company profile
| Founded | 1903, Milwaukee, Wisconsin, USA, as the Compression Rheostat Company |
|---|---|
| Founders | Lynde Bradley (inventor of the compression rheostat, 1901) and Dr. Stanton Allen (investor); Harry Bradley joined in 1904 |
| Name | Allen-Bradley Company from 1909 |
| Ownership | Acquired by Rockwell International in 1985 for about USD 1.65 billion; a brand of Rockwell Automation (NYSE: ROK) since 2001 |
| Headquarters | Milwaukee, Wisconsin, USA |
| Product families | Logix programmable automation controllers (ControlLogix, CompactLogix), legacy SLC 500 and MicroLogix PLCs, Micro800 controllers, POINT, FLEX and Compact I/O, PanelView HMIs, PowerFlex AC drives, contactors, motor starters and soft starters, safety components, Stratix Ethernet switches |
Milestones
- 1901: Lynde Bradley invents the compression rheostat to control the speed of electric motors.
- 1903: The Compression Rheostat Company is formed in Milwaukee with an initial investment of USD 1,000.
- 1904: Harry Bradley joins; a crane controller is shown at the St. Louis World's Fair.
- 1909: The company is renamed Allen-Bradley.
- 1985: Rockwell International acquires Allen-Bradley.
- 2001: Rockwell Automation becomes the company's name; the Allen-Bradley brand marks 100 years in 2003.
Reading Allen-Bradley catalogue numbers
The first digits of an Allen-Bradley catalogue number identify the platform, which tells you what is compatible with what. 1756 is ControlLogix (chassis-based, used for large process and plant control), 1769 is CompactLogix 5370 with Compact I/O, 5069 is CompactLogix 5380 with Compact 5000 I/O, 1734 is POINT I/O, 1794 and 5094 are FLEX and FLEX 5000 distributed I/O, 1746 and 1747 belong to the older SLC 500 family, 1766 is MicroLogix 1400 and 2080 is Micro800. For drives, 25B is PowerFlex 525 and 22B is PowerFlex 40; in a code such as 25B-D010N114, "D" means 380–480 V, "010" is the output current rating, and N114 instead of N104 means the drive has an integrated EMC filter. Many plants in the region still run SLC 500 and older MicroLogix systems, which Rockwell has discontinued, so exact spares and migration to CompactLogix are both common requests.
Where Allen-Bradley products are used
In Oman and the GCC, Allen-Bradley controllers and drives run on oil and gas facilities, water treatment and pumping stations, cement, food and beverage and packaging plants, and on machines supplied by American OEMs. ControlLogix is often the platform for plant control systems, while PowerFlex drives are used on pumps, fans and conveyors.
Allen-Bradley products we list
| Family | Examples |
|---|---|
| ControlLogix | 1756-L85E, 1756-EN2T, 1756-EN2TR, 1756-IF16, 1756-IB32, 1756-PA75, 1756-A10 |
| CompactLogix and Micro controllers | 5069-L320ER, 5069-L340ERM, 1769-L33ER, 1769-L16ER, MicroLogix 1400, Micro820, SLC 500 (1746) |
| Distributed I/O | 1734-AENTR, 1734-IB8, 1734-IE2C, 1734-IB8S safety, 1794-AENTR, 5094-AENTR, 5069-IF8 |
| Operator terminals | PanelView Plus 7 10-inch, PanelView Plus 7 15-inch, PanelView 800, PanelView 5310 |
| Drives, motor control and networking | PowerFlex 525, PowerFlex 755, PowerFlex 4, 150-A180NBD SMC, Stratix 2000, 1783-NATR |
Ordering Allen-Bradley products: what we need
Send the full catalogue number and the series letter from the label (for example 1756-EN2T Series D), because firmware and compatibility can change between series. For drives, add the motor power, voltage and filter option. For a discontinued SLC 500 or MicroLogix part, tell us whether you need the exact spare or a migration proposal.
Facts checked against Rockwell Automation's published company history, October 2026.
Browse Allen-Bradley products by category: PLC & I/O Cards, AC Drives.
Related products
Frequently Asked Questions
Are the channels isolated?
Yes, each channel is isolated from the others and from the backplane.
What resolution does it have?
24 bits.
Can it power a two-wire transmitter?
Yes, in sourcing current mode the channel provides loop power.
What is the calibrated accuracy?
0.05 percent at 25 C, with 0.1 percent module error over temperature.
Does it support HART?
No. For HART use the 1756-IF8H.
Reviews
There are no reviews yet.