Allen‑Bradley 1761-NET-AIC Advanced Interface Converter – RS-232 to RS-485 for DH-485 & DF1 Networks

Allen‑Bradley 1761-NET-AIC Advanced Interface Converter – RS-232 to RS-485 for DH-485 & DF1 Networks插图

Product Overview

The Allen-Bradley 1761-NET-AIC, also marketed as the AIC+ (Advanced Interface Converter), is a compact serial communication interface device developed by Rockwell Automation to bridge RS-232 (DF1 full-duplex or half-duplex) equipment with DH-485 multi-drop RS-485 networks used by MicroLogix™ 1000/1100/1200/1500 controllers, SLC 500™ processors with DH-485 ports, and legacy PanelView™ terminals. The Allen-Bradley 1761-NET-AIC performs both physical layer translation (RS-232 ↔ RS-485) and electrical isolation, allowing a personal computer with a standard RS-232 COM port or USB-to-RS-232 adapter to participate in a DH-485 network for programming, monitoring, or peer-to-peer messaging—functions formerly requiring the discontinued 1747-PIC ISA card or 1747-AIC converter.The Allen-Bradley 1761-NET-AIC is housed in a DIN-rail-mountable enclosure and features one DB-9 female RS-232 port, one 8-pin mini-DIN RS-232 port (for direct connection to MicroLogix Channel 0), and a two-position removable screw-terminal block for the RS-485 (DH-485) network pair (Data A / Data B) plus shield. It provides 500 V AC optical isolation between the RS-232 side and the RS-485 side, breaking ground loops and improving noise immunity in electrically noisy industrial environments. Power can be drawn parasitically from certain MicroLogix processors via the mini-DIN cable (1761-CBL-AM00 or similar) or supplied externally via 24 V DC to the RS-485 terminal block—selectable by an onboard slide switch. Baud rate is set via a DIP switch (supports up to 115.2 kbps) and the unit includes per-port transmit/receive LEDs plus a power LED for immediate visual diagnostics.By enabling modern laptops and programming stations to interface with legacy DH-485 networks, the Allen-Bradley 1761-NET-AIC extends the service life and maintainability of installed MicroLogix and SLC 500 systems that remain prevalent in packaging machinery, material handling, and building automation applications worldwide.

Technical Specifications

Product Model | 1761-NET-AICManufacturer | Rockwell Automation / Allen-BradleyProduct Type | Advanced Interface Converter (AIC+) – RS-232 to RS-485 (DH-485 / DF1)Series | Allen-Bradley 1761 (MicroLogix Accessories)RS-232 Ports | 1 × DB-9 Female (DTE), 1 × 8-pin Mini-DIN (MicroLogix CH0 compatible)RS-485 Port | 2-position + Shield screw terminal (Data A, Data B, Shield/Drain); DH-485 half-duplexIsolation Voltage | 500 V AC RMS continuous between RS-232 side and RS-485 side (optical)Supported Protocols | DH-485, DF1 (Full-Duplex & Half-Duplex), ASCII (pass-through)Baud Rate Selection | DIP switch selectable: 300, 600, 1200, 2400, 4800, 9600, 19.2k, 38.4k, 57.6k, 115.2k bpsPower Supply Options | Parasitic from MicroLogix processor via mini-DIN cable OR external 20–28 V DC @ ≈ 50 mA (24 V DC nom.)RS-485 Termination | Onboard 120 Ω termination resistor selectable via DIP switchIndicators | PWR (green), CH1 Tx/Rx (yellow), CH2 Tx/Rx (yellow)Mounting | 35 mm DIN rail (EN 60715) snap-mountOperating Temperature | 0 °C to +60 °C (32 °F to 140 °F)Storage Temperature | -40 °C to +85 °CHumidity (non-condensing) | 5 % to 95 % RHAgency Approvals | UL Listed, cULus, CE, C-Tick, KCDimensions (H × W × D) | approx. 90 mm × 35 mm × 75 mm (3.54″ × 1.38″ × 2.95″)

Main Features and Advantages

The primary value of the Allen-Bradley 1761-NET-AIC is its ability to modernize access to legacy DH-485 networks without altering existing panel wiring or node addressing. Unlike a simple RS-232-to-RS-485 adaptor, the Allen-Bradley 1761-NET-AIC is protocol-aware in the sense that it correctly handles DH-485 token-pass behavior and DF1 framing, and its 500 V AC isolation prevents damaging ground potential differences between a laptop (earth-grounded via its power supply) and a floating or differently-referenced DH-485 network in the control panel. This isolation is critical when connecting test equipment to running machinery—a direct un-isolated connection can introduce ground loops that disrupt communications or, worse, damage port electronics on the PLC.Flexible powering is another strong point. The Allen-Bradley 1761-NET-AIC can be “parasite-powered” from a MicroLogix 1200/1500 Channel 0 mini-DIN port (which supplies +5 V DC), eliminating the need for a separate 24 V DC supply in simple programming-cart applications. For permanent panel installation on a DH-485 multi-drop, the unit is typically wired to the panel’s 24 V DC supply via the RS-485 terminal block, with the power-source slide switch set accordingly. This dual-power design means one spare Allen-Bradley 1761-NET-AIC serves both as a field technician’s portable DH-485 interface and as a fixed network node converter in OEM machinery.Built-in diagnostics simplify troubleshooting: independent yellow LEDs for each channel show when data is actively being transmitted or received, allowing technicians to confirm cable integrity and baud-rate matching at a glance. The DIP-switch-selectable 120 Ω termination resistor removes the need for an external terminating resistor at the physical ends of the DH-485 trunk. For system integrators maintaining mixed-era Rockwell networks, the Allen-Bradley 1761-NET-AIC effectively replaces both the 1747-PIC (obsolete PIC card) and the 1747-AIC (bulky SLC rack card) in a fraction of the panel space, while remaining fully compatible with RSLinx™ Classic’s DH-485 driver for node browsing, uploading, and downloading.

Application Field

The Allen-Bradley 1761-NET-AIC is most commonly deployed wherever a DH-485 network of MicroLogix or SLC 500 nodes must be accessed from a PC, HMI, or another serial device. In stand-alone packaging machines originally designed around a MicroLogix 1100 or 1200 with DH-485 networking to PanelView 300/600 terminals, the Allen-Bradley 1761-NET-AIC lets maintenance engineers connect a laptop via RS-232 (or via a USB-RS232 dongle) to go online for troubleshooting, recipe changes, or firmware updates—without disturbing the existing DH-485 multi-drop wiring.In legacy material handling systems—conveyor zones, sortation loops—where multiple MicroLogix 1000 processors communicate over a single DH-485 trunk, the Allen-Bradley 1761-NET-AIC provides the programming port interface for the site’s laptop cart. It is also used in building automation retrofits and small-process skids (water treatment, batch blending) that retain DH-485 as the field bus. OEMs often incorporate the Allen-Bradley 1761-NET-AIC inside their control enclosures to give end-users a standardized, isolated DH-485 access point for handheld programmers or SCADA serial interfaces.When migrating older SLC 500 systems that still use DH-485 for panel-mounted operator interfaces, the Allen-Bradley 1761-NET-AIC can interface those legacy HMI nodes to a newer programming PC during the transition period. For any application requiring reliable, isolated conversion between point-to-point RS-232 and multi-drop DH-485 / RS-485 half-duplex networks within the Rockwell Automation ecosystem, the Allen-Bradley 1761-NET-AIC remains the recommended and widely stocked solution.

DCS system

PLC system

servo system

Robot system