1756-OF8 Allen Bradley

The Allen-Bradley 1756-OF8 is an analog output module that is part of the ControlLogix platform. This analog module may be used to control and modulate electrical and field devices, transmit or re-transmits signals for interfacing with measuring and recording instruments or for any other purpose.

The 1756-OF8 comes with Eight (8) analog output channels configurable for +/-10VDC and 0-20 mA analog output signals. It has a resolution of 15 bits across 21 mA – 650 nA/bit and 15 bits across 10.4V – 320 µV/bit with open circuit, short circuit and overvoltage protection capability.

The 1756-OF8 uses R-Ladder DAC, monotonicity with no missing codes module conversion method and provides register data in the form of Integer mode (left justified, 2 s complement) IEEE 32-bit floating point. It has a scan time of 12 ms for floating point format and 8 ms for integer format.

The 1756-OF8 requires removable terminal blocks for wiring of input signals. Appropriate terminal blocks are 1756-TBNH and 1756-TBSH. For 1756-TBNH, applicable wire size is 0.33…2.1 mm2 (22…14 AWG) solid or stranded copper wire, rated at 105 °C (221 °F) or greater, 1.2 mm (3/64 in.) insulation max. for single wire connection and 0.33…1.3 mm2(22…16 AWG) solid or stranded copper wire, rated at 105 °C (221 °F) or greater, 1.2 mm (3/64 in.) insulation max. for double wire connection. When 1756-TBSH is used, appropriate wire size is 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 (3/64 in.) insulation max. Only single wire connection is applicable for the 1756-TBSH.

When operational, it has an offset drift of 50 ppm/degrees Celsius and 0.1 ppm/degrees Celsius and temperature-dependent gain drift of 25 ppm/degrees Celsius and 50 ppm/degrees Celsius (current). The module has a scan time of 12 milliseconds for floating point and 8 milliseconds for integer and has an overall module error of 0.15% (in voltage mode) and 0.3% (in current mode). The1756-OF8 module has an isolation voltage of 250 Volts using reinforced insulation tested 1350 Volts AC for 2 seconds between the output channels and the backplane. It has a T4A (North America), T4 (ATEX), and T4 (IEC) temperature codes and comes in an open-style enclosure. The 1756-OF8’s operational temperature ranges between 0 and 60 degrees Celsius and it is designed to maintain its function at a shock rate of 30G and a vibration of 2G at 10 to 500 Hertz.

Allen Bradley ControlLogix Analog Output Module with 8 Current-Voltage Outputs