The Allen-Bradley 1771-NOC (1771NOC PLC-5 Analog Output Module) provides eight isolated 4-20 mA current outputs for high-resolution analog signal generation within a 1771 I/O system.

Catalog References

The supplied catalog information identifies 1771-NOC as a PLC-5 high-resolution analog output module. Listed alternate references are 1771-NOC/A, 1771-NOC/B, and 1771-NOC/C. The supplied data does not define the functional differences between these revisions.

Hardware Specifications

Analog Current Output Characteristics

The 1771-NOC provides eight isolated analog output channels, with each channel specified for a 4-20 mA current signal. The module is identified as a high-resolution analog output device for the PLC-5 1771 I/O platform.

The supplied information does not state individual channel accuracy, resolution in bits, load resistance, output update time, calibration method, or channel-to-channel isolation rating. These values are therefore not inferred.

For field wiring, each 4-20 mA circuit should be treated as an analog instrumentation loop. Signal conductors should be routed separately from high-current switching and motor wiring where practical to reduce electrical interference.

Ordering Configuration

• 1 x Allen-Bradley 1771-NOC Analog Output Module
• Catalog reference: 1771NOC
• 8 x isolated 4-20 mA analog outputs
• Alternate catalog references: 1771-NOC/A, 1771-NOC/B, 1771-NOC/C
• Compatible 1771 chassis and field wiring accessories are not specified as included
• External loop devices and field power supplies are not identified as included components

Installation and Wiring Guidelines

Module Installation

• Verify compatibility with the installed 1771 I/O chassis before insertion.
• Inspect the module connector and chassis interface for contamination or mechanical damage.
• Install the module according to the applicable 1771 system procedure.

Analog Signal Wiring

• Use suitable twisted-pair instrumentation wiring for 4-20 mA circuits.
• Keep analog signal wiring away from motor leads, contactors, and other high-current conductors.
• Avoid unnecessary cable loops and excessive parallel routing with switching circuits.

Shielding and Grounding

• Apply the field instrument grounding arrangement specified by the system design.
• Ground cable shields according to the installation documentation to avoid unintended ground-current paths.
• Do not connect signal shields at multiple points unless the system grounding design explicitly requires it.

Commissioning

• Verify loop polarity before energizing each output circuit.
• Check field device compatibility with the 4-20 mA signal range.
• Confirm the PLC output configuration before placing the analog channels into service.

Frequently Asked Questions

• How many analog outputs does the 1771-NOC provide?

  The supplied specification identifies 8 analog output points. Each output is specified as an isolated 4-20 mA current output.

• What signal does the module generate?

  The module generates 4-20 mA analog current signals. The supplied data does not specify additional voltage output modes.

• Are the outputs isolated?

  Yes. The supplied product description explicitly identifies the 8 current outputs as isolated. The isolation rating is not provided.

• Is the module high resolution?

  Yes. The supplied product information identifies the device as a PLC-5 high-resolution analog output module, but no bit resolution is stated.

• What is the module weight?

  The listed product weight is 0.68 kg. The supplied shipping dimensions are 3.2 x 15.5 x 25.5 cm.

• Is power consumption specified?

  No. The supplied technical information does not provide a power consumption or backplane current value, so no numerical value is assigned.

• Can the module be hot swapped?

  Hot-swap capability is not confirmed by the supplied information. Installation and removal should follow the applicable 1771 system procedure.

• What operating temperature is specified?

  No operating temperature range is included in the supplied data. The applicable Allen-Bradley documentation should be consulted for environmental limits.