Allen-Bradley 1771-IFF PLC5 Analog Input Module

1771-IFF 16-Channel Fast Analog Input by Allen-Bradley

Product Introduction

The Allen-Bradley 1771-IFF is a high-performance analog input module from the PLC5 series. This module excels in applications requiring fast and accurate data acquisition. It uses block transfer programming to communicate with the PLC processor. This method ensures efficient data exchange between the module and the controller. The 1771-IFF stands out with its exceptional speed. It delivers a channel update time of just 5 ms for 8 channels. This speed makes it suitable for fast-moving processes. Additionally, its conformal coating protects against harsh environmental conditions.

Key Technical Specifications

This module offers versatile channel configuration options. You can choose either Sixteen (16) single-ended inputs or Eight (8) differential inputs. Differential inputs are ideal for reducing noise in electrically noisy environments. Single-ended inputs work well for simpler installations with shorter cable runs.

The 1771-IFF supports a broad range of input signals. For voltage, it accepts 0-5V, 1-5V, -5 to +5V, and -10 to +10V DC. For current, it handles 4-20mA, 0-20mA, -20 to +20mA, and -40 to +40mA. This extended current range is a distinctive feature. It accommodates sensors with unusually wide output ranges. The module provides a 12-bit binary resolution, with 12 bits plus a sign bit for ranges that include both positive and negative values.

Speed is the defining advantage of the 1771-IFF. The channel update time is only 5 ms for 8 channels and 10 ms for 16 channels. This rapid update rate allows the PLC to respond quickly to process changes. The module uses a natural binary or BCD data format, scaling to +/-9999. It draws 750 mA from the backplane and requires no external power supply. The maximum power dissipation is 2.5 Watts, with a thermal dissipation of 8.52 BTU/hour.

Conformal Coating Protection

The 1771-IFF includes a conformal coating as a standard feature. This polymeric film protects the circuit board from moisture and humidity. It also resists corrosion caused by airborne contaminants. Additionally, it offers some protection against dust and dirt. This coating significantly enhances the module's reliability in harsh environments. Therefore, the 1771-IFF performs exceptionally well in chemical plants, offshore platforms, and food processing facilities.

Mechanical and Environmental Parameters

This module is designed for rack mounting in a 1771 chassis. It occupies a single slot in the rack. The front panel includes a green RUN LED and a red FAULT LED. These indicators provide immediate visual feedback on the module's operational status. The module includes optoelectrical isolation. This feature protects the control system from electrical transients and ground loops. It also includes digital filtering to reduce electrical noise on input signals. This filtering results in more stable readings in electrically noisy environments.

Installation Guidelines

Installing the Allen-Bradley 1771-IFF follows a simple procedure. First, ensure that the chassis is powered down completely. Next, align the module with the chosen slot in the 1771 I/O chassis. Slide it in carefully until it seats firmly against the backplane. Then, secure the module using the retaining screws provided.

Proper keying is critical for correct installation. Place the keying bands between pins 10 and 12 for the lower connector. For the upper connector, place them between pins 24 and 26. This keying configuration ensures that only a 1771-IFF module can be inserted into that slot. The module includes a 1771-WG wiring arm. This accessory simplifies wiring and maintenance. You can replace the module without disconnecting any field wiring. This feature significantly reduces system downtime.

Configuration and Digital Features

The 1771-IFF uses block transfer programming for communication. This method efficiently transfers input data to the processor's data table. It also transfers configuration words back to the module. Configuration parameters offer excellent flexibility. You can enable real-time sampling to regulate the sampling time. This feature helps minimize signal fluctuations.

You can also scale the input values to engineering units. Scaling displays data in meaningful measurements, such as PSI, °C, or liters per minute. This eliminates the need for manual calculations in your logic program. The data format parameter lets you choose between natural binary and BCD scaling. Therefore, you can tailor the module's behavior to suit your specific application requirements.

Fault Response and Safety

The 1771-IFF includes a valuable fault response feature. If input communication becomes disrupted, the module responds automatically. It uses the default user configuration to handle the fault condition. This automatic response provides a predictable and safe reaction. It limits the extent of the fault and prevents unsafe process behavior. Consequently, this feature enhances overall system reliability and safety.

Process Variable Applications

This analog input module excels at measuring various process variables. It works with sensors for Temperature, Pressure, Level, and Flow. Additionally, it can measure Speed, Viscosity, and pH. Other common applications include Vibration and Displacement monitoring. The fast update rate of the 1771-IFF makes it particularly suitable for dynamic processes. These include flow control, pressure regulation, and high-speed mixing operations. The module converts the sensor's analog signal into a proportional digital value. The PLC then uses this data for control decisions, alarms, or data logging.

Packaging and Shipping

All modules undergo careful packaging before shipment. We use anti-static bags to prevent electrostatic damage. The packaging also provides sufficient cushioning against physical impacts. Please note that the packaging list does not include certificates or warranties. Each shipment includes the module and the 1771-WG wiring arm. We ship globally using trusted couriers such as FedEx, UPS, and DHL.

Packaging List

• Allen-Bradley 1771-IFF Analog Input Module (1 unit)

• 1771-WG Wiring Arm (1 unit)

• Installation Instructions (Printed Quick Guide)

Frequently Asked Questions (FAQ)

1. What is the main advantage of the 1771-IFF over other PLC5 analog input modules?
The 1771-IFF offers a significantly faster update time of 5 ms for 8 channels. This speed makes it ideal for fast-moving processes and dynamic control applications.

2. What is the -40 to +40 mA current range used for on the 1771-IFF?
This extended current range accommodates sensors with unusually wide output signals. It provides greater flexibility when connecting non-standard transducers to the module.

3. Does the 1771-IFF require external power to operate?
No, the 1771-IFF draws all its operational power from the chassis backplane. It does not require any external power supply connection.

4. What is the function of the conformal coating on the 1771-IFF?
The conformal coating is a protective polymeric film. It shields the circuit board from moisture, humidity, and corrosive contaminants. This coating enhances reliability in harsh environments.

5. How does the 1771-IFF respond to a communication fault?
The module automatically uses the default user configuration to respond to faults. This provides a predictable and safe system behavior, limiting the extent of any potential fault.