Allen-Bradley 1746SC-INO4I Spectrum Controls Isolated Analog Module

Description

Key Technical Specifications

Product Introduction & Supply Chain Strategy

The 1746SC-INO4I is a high-precision 4-channel isolated analog current output module engineered specifically for Allen-Bradley SLC 500 system racks. Built with 500 V DC channel-to-channel isolation, it drives critical control valves, positioners, and variable speed drives without ground loop distortion or cross-channel noise interference.

This product is a Brand New Surplus unit. It is not used, not pulled from a decommissioned plant, and not refurbished. All modules undergo rigorous quality verification to ensure OEM-level reliability.

Securing the 1746SC-INO4I as New Surplus provides key Total Cost of Ownership (TCO) benefits for legacy facilities. Buying verified New Surplus avoids the severe risks of refurbished modules—such as degraded digital-to-analog converter (DAC) chips or leaky isolation capacitors—while eliminating extended lead times on hard-to-find legacy SLC 500 hardware.

Installation & Configuration Guide

Stage 1: Pre-Installation (Prep & Safety)

1. Open the main incoming AC power breaker feeding the SLC 500 rack and apply Lock-Out/Tag-Out (LOTO).
2. Attach a grounded anti-static wrist strap connected to the enclosure frame ground terminal.
3. Verify that module jumpers and address configuration DIP switches match the target slot configuration.
4. Record terminal wiring connections on the existing 1746-RT25 removable terminal block before removal.

Stage 2: Removal

1. Press the top and bottom releases on the 1746-RT25 removable terminal block and pull it straight forward.
2. Press the upper and lower module retention tabs on the 1746SC-INO4I chassis card inward.
3. Slide the board straight out along the chassis guide tracks to avoid twisting the rear backplane connector.
4. Store the removed card inside an ESD shielding bag.

Stage 3: Installation (Clone & Seat)

1. Confirm that DIP switch settings on the replacement 1746SC-INO4I card match the original module identically.
2. Align the top and bottom edges of the card with the designated chassis card guides.
3. Slide the card inward until the top and bottom retention tabs lock into the chassis frame with a distinct click.
4. Re-insert the pre-wired removable terminal block until both side latches engage cleanly.

Stage 4: Power-On & Testing

1. Re-apply power to the SLC 500 chassis power supply unit.
2. Verify CPU and module status LEDs to confirm successful backplane initialization.
3. Open RSLogix 500 to verify the slot configuration and ensure output data words transfer cleanly.
4. Force test values in ladder logic to verify 4–20 mA current loops using a calibrated field meter.

1746SC-INO4I

Firmware/Software Versions & Upgrade Notes

The 1746SC-INO4I maps directly into the SLC 500 memory image via standard output data registers.

• Software Compatibility: Fully supported in RSLogix 500 software versions 4.0 and higher using generic 1746 I/O setup profiles.
• Power Supply Headroom: Verify that the 24 V DC auxiliary rail on the chassis power supply (1746-P1, P2, or P4) has at least 250 mA of available current capacity to prevent backplane brownouts during 20 mA full-scale output.
• Fault State Settings: Match hardware DIP switch settings for module fault modes (e.g., hold last state vs. zero output) to maintain process safety upon communication failure.

Frequently Asked Questions (FAQ)

Q: Is this 1746SC- module brand new or has it been pulled from a decommissioned cabinet?

A: This product is a Brand New Surplus unit. It is not used, not pulled from a decommissioned plant, and not refurbished. All modules undergo rigorous quality verification to ensure OEM-level reliability.

Q: Why is New Surplus preferred over a cheaper refurbished analog card?

A: Our pricing reflects the cost of securing genuine New Surplus inventory globally. It may be 20–30% higher than a refurbished gamble, but it is substantially less than OEM list prices, and it buys you 100% peace of mind. Refurbished analog output cards often carry aged components that introduce calibration drift or signal ripple into sensitive control loops.

Q: Is the 1746SC- manufactured directly by Allen-Bradley or Spectrum Controls?

A: It is manufactured by Spectrum Controls as an official Allen-Bradley Encompass Partner product. It is engineered specifically for direct plug-and-play operation in Allen-Bradley SLC 500 racks.

Q: Does this module require an external 24 V DC loop power supply?

A: Yes. The 1746SC- requires external 24 V DC field loop power connected across its terminal block to drive isolated 4–20 mA signals to field devices.

Q: What warranty applies to this New Surplus module?

A: We back this card with a full 1-year functional replacement warranty from the date of shipment, ensuring continuous system protection and zero process downtime.