1756-OF8H Allen Bradley Rockwell Analog Output Module

Product Parameters

Basic Information:

Manufacturer: Allen-Bradley (Rockwell Automation)

Model: 1756-OF8H (Series A)

Type: Analog Output Module with HART Protocol

Compatible Systems: ControlLogix series (compatible with PLC-5 via adapters)

Installation: Occupies one slot in a 1756 ControlLogix chassis, suitable for local or distributed I/O configurations

Module Location: Can be installed in any slot of the ControlLogix chassis

Electrical Parameters:

Output Channels: 8 single-ended analog outputs

Output Signal Ranges:

Voltage: ±10V DC

Current: 0–20 mA (commonly 4–20 mA)

Resolution:

Voltage: 15 bits across 20.78V (650 µV/bit)

Current: 15 bits across 21 mA (650 nA/bit)

Backplane Current:

230 mA @ 5.1V DC

230 mA @ 24V DC

Backplane Power: 6.54 W (maximum)

Power Dissipation: 4.92 W (maximum)

Thermal Dissipation: 16.78 BTU/hour (maximum)

Output Impedance:

Voltage: <1 Ω

Current: >1 MΩ

Drive Capability:

Voltage: 1000 Ω (minimum load)

Current: 0–700 Ω

Calibration Interval: Recommended every 12 months

Module Error:

Voltage: 0.15%

Current: 0.3%

Offset Drift:

Voltage: 100 µV/°C

Current: 200 nA/°C

Gain Drift:

Voltage: 25 ppm/°C

Current: 50 ppm/°C

Overvoltage Protection: ±24V DC (current mode)

Short-Circuit Protection: Electronically limited to 21 mA or less (current mode)

Isolation Voltage: 50V continuous (output channels to backplane), tested at 1500V AC for 60 seconds (basic insulation)

HART Scan Time: 1 second (typical) for all 8 channels

Connection and Wiring:

Removable Terminal Blocks (RTBs):

1756-TBNH: 20-position NEMA screw clamp block

1756-TBSH: 20-pin spring clamp block

Wire Size:

1756-TBNH: 0.33–2.1 mm² (22–14 AWG) solid or stranded copper wire, rated at 105°C (221°F) or greater, 1.2 mm insulation max (single or double wire connection)

1756-TBSH: 0.33–2.1 mm² (22–14 AWG) solid or stranded shielded copper wire, rated at 105°C (221°F) or greater, 1.2 mm insulation max (single wire only)

Torque: 1.36 Nm (12 lb-in) for 1756-TBNH

Environmental Specifications:

Operating Temperature: 0°C to 60°C (32°F to 140°F)

Storage Temperature: -40°C to 85°C (-40°F to 185°F)

Relative Humidity: 5% to 95% (non-condensing)

Vibration: 2G @ 10–500 Hz

Shock: 30G (operating)

Enclosure Type: Open-type

Temperature Codes: T4 (North America, IEC, ATEX)

Other:

Conversion Method: R-Ladder DAC, monotonicity with no missing codes

Data Formats: IEEE 32-bit floating point, Integer (left-justified, 2’s complement)

HART Protocol: Supports HART 5, 6, and 7 for communication with field devices

Certifications: UL, CSA, CE, C-TICK, ATEX, FM, KC, IECEx, ABS

Functions

Analog Output Control:

Provides 8 single-ended analog output channels configurable for ±10V DC or 0–20 mA (commonly 4–20 mA), enabling precise control of analog devices like valves, actuators, or variable frequency drives (VFDs).

HART Protocol Support:

Integrates HART communication for each channel, allowing configuration, diagnostics, and monitoring of HART-capable field devices (e.g., transmitters, valves).

Enables remote access to device data, such as process variables, status, and diagnostics, without additional wiring.

High-Resolution Output:

Offers 15-bit resolution for voltage (650 µV/bit) and current (650 nA/bit), ensuring precise control for demanding applications.

Protection Features:

Overvoltage Protection: Protects against ±24V DC in current mode.

Short-Circuit Protection: Electronically limits current to 21 mA or less to prevent damage.

Open-Circuit Detection: Detects open circuits in current mode (below 0.1 mA), enhancing system reliability.

Diagnostics and Alarming:

Provides real-time channel sampling and onboard data alarming for immediate fault detection (e.g., over/under range, open circuit).

HART protocol enables advanced diagnostics, such as device health monitoring and predictive maintenance.

Flexible Data Handling:

Supports IEEE 32-bit floating point and Integer data formats for compatibility with various control algorithms.

Uses R-Ladder DAC for accurate and monotonic signal conversion.

System Integration:

Integrates with ControlLogix controllers via ControlNet, EtherNet/IP, or DeviceNet networks.

Supports local or distributed I/O configurations, compatible with Studio 5000 Logix Designer for configuration and diagnostics.

Modular Design:

Supports Removal and Insertion Under Power (RIUP) with removable terminal blocks (1756-TBNH, 1756-TBSH), simplifying maintenance and reducing downtime.

Application Scenarios

Industrial Process Control:

Controls analog devices like valves, pumps, or actuators in industries such as chemical processing, oil and gas, or water treatment, where precise modulation is critical.

HART protocol enables integration with smart field devices for real-time diagnostics and configuration, ideal for flow, pressure, or temperature control.

Manufacturing Automation:

Drives VFDs or servo motors in production lines for automotive manufacturing, packaging, or material handling.

Ensures precise speed or position control in conveyor systems or robotic arms.

Smart Instrumentation:

Interfaces with HART-capable devices (e.g., transmitters, positioners) to monitor process variables and device health, reducing downtime in complex systems like refineries or power plants.

Distributed Control Systems:

Used in distributed I/O setups via ControlNet or EtherNet/IP, enabling centralized control of remote analog devices in large-scale facilities.

Legacy System Upgrades:

Integrates with PLC-5 systems (via adapters) or serves as a key component in modernizing to ControlLogix platforms, maintaining compatibility with legacy infrastructure.

Harsh Environment Applications:

Robust design with vibration (2G) and shock (30G) resistance makes it suitable for demanding environments like mining, marine, or heavy machinery control.

Advantage Products:

All items are Distributor Ready-stock Genuine Brand-new Supplying, please inform us if the other conditions are needed, Used, Open-box, Refurbished, etc.

Many Available just wait for you, feel free to ask to get better deal!!!

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