1769-IF4 AB Compact I/O Input Module Ser B PLC Module 1769IF4 Brand New
Allen-Bradley 1769-IF4 | CompactLogix 4-Channel Analog Input Module
Part Number: 1769-IF4
Manufacturer: Allen-Bradley / Rockwell Automation (USA)
Product Type: Analog Input Module — 4 Channel, Voltage/Current
Product Family: 1769 Compact I/O (CompactLogix)
Overview
The 1769-IF4 is Allen-Bradley's four-channel analog input module for the 1769 Compact I/O platform — the CompactLogix family's primary analog input module for process signal acquisition from field transmitters and sensors.
Four independently configurable channels accept both voltage and current signals, covering all standard ranges used in industrial automation: 4-20mA from loop-powered transmitters, 0-10V from sensors with voltage outputs, and various span variants.
This module is essential for CompactLogix control systems where process variables such as temperature, flow, level, or pressure measurements need to enter a Logix controller. Its four channels handle a significant portion of typical process cell analog input requirements, with multiple modules expandable as applications grow.
Important Note: The 1769-IF4 does not supply loop power to connected 2-wire transmitters. An external 24V DC supply is required for 2-wire 4-20mA transmitters. 4-wire transmitters with their own power supply connect directly without this consideration.
Key Specifications
| Parameter |
Value |
| Part Number |
1769-IF4 |
| Manufacturer |
Allen-Bradley / Rockwell Automation |
| Product Type |
4-Channel Analog Input Module |
| Platform |
1769 Compact I/O (CompactLogix / MicroLogix 1500) |
| Input Channels |
4 (individually configurable) |
| Current Ranges |
0-21mA, 3.2-21mA |
| Voltage Ranges |
±10.5V, 0-10.5V, 0-5.25V, 1-5.25V DC |
| ADC Technology |
Delta-Sigma |
| Resolution |
14-bit unipolar / 14-bit + sign bipolar |
| Supply Voltage |
24V DC (20.4-26.4V) |
| Backplane Current |
120mA at 5V / 60mA at 24V |
| Wiring |
Plug-in screw terminal block |
| Mounting |
DIN rail or panel |
| Operating Temp |
0°C to 60°C |
| Certifications |
UL, C-UL, CE, KC, GOST, CCC, C-TICK, Marine |
Delta-Sigma ADC Technology
The 1769-IF4 utilizes Delta-Sigma (ΔΣ) analog-to-digital converter technology, which is particularly well-suited for industrial measurement applications.
Delta-Sigma converters oversample input signals at high rates and employ digital filtering to extract measurements, providing excellent noise rejection exceeding 60 dB common mode rejection. This noise immunity is crucial in industrial environments where 24V switching noise, drive PWM harmonics, and relay contact transients can interfere with signal integrity.
The 14-bit resolution provides 16,384 counts across the input span. For a 4-20mA channel, this translates to approximately 1 µA per count — more than adequate for most process control applications where sensor accuracy is typically the limiting factor.
Channel Configuration and Data Formats
Each channel on the 1769-IF4 is independently configurable, allowing a single module to simultaneously handle different signal types — for example, 4-20mA current input on one channel, ±10V voltage input on another, and 0-5V voltage on a third.
The module supports four data formats for digitized output to the controller:
- Engineering Units: Scaled to the physical quantity
- Scaled for PID: Normalized for direct entry into Logix PID instructions
- Percent Range: 0-100% representation
- Raw Data: Direct ADC count values
Most applications utilize engineering units or scaled-for-PID formats. Scaled-for-PID maps inputs directly to the ±16383 range used by PIDE instructions, eliminating additional scaling requirements in control programs.
Open-Circuit Detection and Diagnostics
The 1769-IF4 provides open-circuit detection on current input channels. If a 4-20mA loop is broken due to disconnected wiring or transmitter failure, the module detects the absence of current and sets an under-range error bit.
This diagnostic capability allows controllers to trigger alarms, set PID to manual mode, or initiate safe shutdown sequences. The module also sets non-fatal system error indicators monitorable by HMI systems via SCADA.
Auto-calibration is performed when channels are first enabled or when configuration changes occur, ensuring accuracy from the first scan without manual calibration procedures.
Frequently Asked Questions
Q1: A 4-20mA pressure transmitter is connected to the 1769-IF4, but the reading stays at exactly 0 in the controller tag. The channel LED is on. What should be checked?
A zero reading with the LED on indicates the channel is receiving no current. Verify the transmitter is powered — the 1769-IF4 does not provide loop power, so 2-wire transmitters require an external 24V supply in series with the loop. Check continuity from the power supply through the transmitter and back to the module's current input terminal. Also confirm the channel is configured for current input (not voltage) in Studio 5000 module properties.
Q2: The module is configured for 4-20mA on all four channels. What does the under-range alarm indicate, and how should it be handled in the control program?
The under-range alarm activates when measured current falls below approximately 3.2mA — below the normal 4mA zero-scale. This typically indicates a broken loop or transmitter power loss. Monitor the ModuleFaults.InputStatus bit for each channel. When under-range is detected, move associated PID instructions to manual mode and set process alarms. Do not use the reading for control when the fault bit is active.
Q3: Can the 1769-IF4 be used with MicroLogix 1500 as well as CompactLogix controllers?
Yes — the 1769-IF4 is compatible with both MicroLogix 1500 and 1769 CompactLogix platforms. The module installs in a 1769 Compact I/O expansion rail connected to either controller. Configuration is done through RSLogix 500 for MicroLogix 1500 or Studio 5000/RSLogix 5000 for CompactLogix. Physical module and wiring are identical regardless of controller.
Q4: How far from the system power supply can the 1769-IF4 be installed?
Compact I/O modules must be installed within 8 module positions of the system power supply. Beyond 8 positions, an additional 1769 expansion power supply must be inserted. This limit is based on backplane current budget — each module draws current from the POINTBus, and exceeding the limit without expansion supply causes erratic module behavior or configuration errors.
Q5: Is the 1769-IF4's plug-in terminal block removable for easier wiring?
Yes — the 1769-IF4 uses plug-in (removable) terminal blocks. This practical advantage allows field wiring to connect to the terminal block, which can be unplugged from the module without disturbing field wiring. This facilitates module testing or replacement while maintaining field connections, saving significant time in high-channel-count systems.
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