Technical Overview of the 1756-IB32 Input Module

The Allen-Bradley 1756-IB32 reads digital DC signals from field devices. These devices include push buttons, limit switches, and proximity sensors. The module mounts into any slot of a ControlLogix chassis. It uses electronic keying for safe and flexible replacement. The 1756-IB32 covers many 12V and 24V DC applications.

Input Specifications and Electrical Ratings

The 1756-IB32 operates with a voltage range of <span style=”color:#e03e2d;”>10 to 31.2 Volts DC</span> . Nominal input voltage is 24 Volts DC. The voltage category is 12/24 Volts DC sink. Minimum operating current is 2 mA at 10 Volts DC. Maximum operating current is 5.5 mA per channel. Off-state maximum current is 1.5 mA.

The Allen-Bradley 1756-IB32 has 32 inputs divided into two groups. Each group contains 16 isolated input channels. The backplane draws 120 mA at 5.1 Volts. It draws only 2 mA at 24 Volts. Maximum power dissipation is 6.2 Watts at 60°C. Thermal dissipation is 21.1 BTU per hour at the same temperature.

Input Delay and Filter Configuration

The 1756-IB32 offers precise control over signal timing. Hardware delay for OFF to ON is 380 µs maximum plus filter time. Hardware delay for ON to OFF is 420 µs maximum plus filter time. You can configure the filter time to match your application.

Filter settings for OFF to ON are 0, 1, or 2 milliseconds. Filter settings for ON to OFF are 0, 1, 2, 9, or 18 milliseconds. Longer filters reject electrical noise on the 1756-IB32 inputs. Shorter filters give faster response to real-world signals. This flexibility makes the 1756-IB32 suitable for noisy industrial environments.

Environmental and Physical Data

The Allen-Bradley 1756-IB32 operates from 0°C to 60°C (32°F to 140°F). Storage temperature range is -40°C to 85°C (-40°F to 185°F). The module has an open-style enclosure. Humidity tolerance is 5% to 95% non-condensing. Shock rating is 30G per IEC 60068-2-27. Vibration rating is 2G at 10 to 500 Hz.

Installation and Wiring Guidelines

The 1756-IB32 requires a removable terminal block (RTB) for field wiring. Compatible RTBs are the 1756-TBCH or 1756-TBS6H. Both are 36-pin terminal blocks. The 1756-TBCH accepts 22-14 AWG copper wire. The 1756-TBS6H works with shielded cable for noisy environments.

Insert the 1756-IB32 into any slot of your ControlLogix chassis. The module uses electronic keying for safe configuration. Connect your 24V DC sink devices between the input terminal and the common terminal. Each of the two groups on the 1756-IB32 has its own common return.

Configure the module properties in your Studio 5000 project. Set the Request Packet Interval (RPI) for your scan time needs. Adjust channel filters to balance speed and noise rejection. Monitor module status through the diagnostic page of the 1756-IB32.

Package Contents

When you order the Allen-Bradley 1756-IB32, you will receive the following items:

• One Allen-Bradley 1756-IB32 ControlLogix digital DC input module.

• One product information sheet with basic handling instructions.

• No removable terminal block is included (order 1756-TBCH or 1756-TBS6H separately).

• No chassis or power supply is included.

• No wiring labels or markers are included.

Frequently Asked Questions (FAQ)

1. What is the difference between sinking and sourcing on the 1756-IB32?

The Allen-Bradley 1756-IB32 is a sinking input module. This means the input channel provides a path to DC common. Your field device must source positive voltage to the 1756-IB32 input terminal.

2. Can I mix 12V and 24V devices on the same 1756-IB32 module?

Yes, the 1756-IB32 accepts any voltage from 10 to 31.2V DC per channel. However, each of the two groups shares a common return. All channels within one group must use the same nominal voltage for reliable operation.

3. Why does the 1756-IB32 have configurable input filters?

Input filters on the Allen-Bradley 1756-IB32 remove electrical noise from switch contacts. Longer filters prevent false triggering from vibration or EMI. Shorter filters give faster response for high-speed signals. Choose the filter time based on your specific sensor and environment.

4. What terminal block does the 1756-IB32 require?

The 1756-IB32 uses a 36-pin removable terminal block. Two compatible models are 1756-TBCH (standard screw) and 1756-TBS6H (shielded). Both must be purchased separately from the 1756-IB32 module itself.

5. How do I know if the 1756-IB32 is working properly?

The Allen-Bradley 1756-IB32 provides diagnostic data through Studio 5000. Open the module properties and check the Module Info tab. This screen shows minor and major faults. It also displays the backplane status and overall health of the 1756-IB32.