Overview
The Allen-Bradley 1747-AIC /B is an isolated link coupler designed to connect SLC 500 fixed and modular processors to DH-485 token-passing networks. The coupler provides a 6-position removable terminal block for connection to the DH-485 communication cable. If connected to an SLC 500 processor, the link coupler is powered via the communication port; otherwise, an external 24VDC power supply is required. The Series B variant is electrically identical to Series A but uses terminal numbers instead of legacy signal names.
Key Features
- Isolated link coupler for DH-485 communication that allows multiple devices such as SLC processors, HMIs, and programming terminals to communicate safely with electrical isolation.
- Compatible with both SLC Fixed and modular style hardware and has communication ports to allow a connected SLC controller to connect to a programming workstation and to a DH485 network.
- Panel-mounted external device with no chassis slot requirement
- Supports daisy-chain topology with low current draw (0.085 A @ 24V DC)
- Catalog Number 1747-C11, 304.8 mm (12 in.) cable supplied with the link coupler.
Technical Specifications
The following specifications apply to the 1747-AIC /B series:
- Power Supply: 24V DC (derived from processor or external supply)
- Current Load: 0.085 A @ 24V DC
- Communication Interface: DH-485 (RS-485 based, token-passing)
- Terminal Block: 6-position removable
- Mounting: Panel-mounted (external to processor chassis)
- Cable Standard: Belden #3106A or #9842 shielded twisted-pair
- Maximum Network Length: 1219 m (4000 ft) total cable distance from first node to last node on the network
- Topology: Daisy-chain
- Certifications: UL Listed for hazardous locations (Class 1 Groups A, B, C, D, Div. 2)
- Compatibility: SLC 500, SLC 501, SLC 502, SLC 503 processors
- Series: B (internally identical to Series A; terminal numbering clarified)
Typical Applications
The 1747-AIC Link coupler allows an SLC 500 fixed style or modular style processor to be communicated or multiplexed with a programming workstation and DH485 network. It has DH485 communication terminal, Peripheral connection and a CPU port, enabling the connected processor to be connected to a DH485 network while allowing simultaneous communication with a programming workstation. Commonly deployed in manufacturing process control, discrete automation, and legacy industrial Ethernet migration scenarios.
Compatibility & Replacements
The 1747-AIC /B is the standard isolated link coupler for all SLC 500 DH-485 networking. The internal circuitry of the Series A is the same as Series B. Alternative communication modules for SLC 500 include the 1747-KE (RS-232/DH-485 interface) and 1747-PIC (Personal Interface Converter), though these require additional cabling. For modern systems, Ethernet modules (1747-L5x series) offer higher bandwidth but do not replace DH-485 infrastructure. Used 1747-AIC /B units are widely available and are direct replacements for field retrofits and system expansions.
