Output Module Allen-Bradley 1756-OF8IH ControlLogix HART

Product Overview

The Allen-Bradley 1756-OF8IH is a high-performance output module. It belongs to the ControlLogix HART I/O Module series. This module offers eight isolated differential outputs. Each channel includes one HART modem. It supports current ranges of 0-20 mA and 4-20 mA. The module provides a 15-bit resolution across 24 mA. It delivers precise analog control for industrial processes.

This module features HART protocol support for versions 5, 6, and 7. It allows both read and write capabilities. The 1756-OF8IH ensures reliable communication with smart field devices. Its open-style enclosure makes it suitable for cabinet mounting. The backplane current draw is 400 mA at 24V DC.

Application Scenarios

This output module works well in process control environments. It is ideal for chemical plants and oil refineries. The module controls valves, actuators, and positioners. It also manages variable frequency drives and other analog devices. HART communication enables remote calibration and diagnostics. This reduces maintenance time and improves system uptime.

Use the module in distributed control systems. It fits into water treatment facilities and power generation plants. The isolated outputs protect sensitive equipment from ground loops. Each channel operates independently for maximum flexibility.

Technical Specifications

The module has an output range of 0-20 mA and 4-20 mA. It provides open circuit detection and short-circuit protection. The output current is electronically limited to 21 mA or less. The drive capability ranges from 50 to 750 ohms. The load reactance is 10 µH.

Settling time is less than 100 ms with HART enabled. It is less than 23 ms with HART disabled. Calibration accuracy is 0.15% at 4-20 mA. The calibration interval is 12 months. Offset drift is ±3 ppm full-scale. Gain drift is ±4 ppm. Module error is 0.3% at 4-20 mA.

Data format uses IEEE 32-bit floating point. The output conversion method is R-Ladder DAC. Isolation between outputs and backplane is 250V reinforced insulation. It is tested at 3535V DC for 60 seconds. Output-to-output and output-to-ground isolation is 250V basic insulation. It is tested at 2120V DC for 60 seconds.

The working temperature range is 0-60 °C. Humidity range is 5-95% non-condensing. The ambient temperature is 60 °C. The temperature code is T4A in North America. It is also T4ATEX and EIC compliant.

Installation & Maintenance Guide

Install the module in a ControlLogix chassis. Ensure the backplane power is off before insertion. Align the module with the guide rails. Push it firmly until it locks into place. Connect the field wiring to the terminal block. Use copper wire for all circuit connections.

Perform calibration every 12 months for best accuracy. Use a certified current source for calibration. Check for open circuits or short circuits regularly. Keep the module free from dust and moisture. Ensure proper ventilation around the module. Do not exceed the specified temperature range.

Packing List

One Allen-Bradley 1756-OF8IH output module. One installation guide. One warranty card. No additional accessories are included. The module is shipped in an anti-static bag. Shipping is done via FedEx, UPS, or DHL.