Allen Bradley 1734-485ASC

Brand: Allen Bradley
Model: 1734-485ASC

Inventory situation: Goods are available in stock.

Product features

The Allen Bradley 1734-485ASC is a reliable RS-485 serial communication module specifically designed for Allen Bradley's Point I/O distributed I/O system. It serves as a critical link between Point I/O modules and industrial field devices-such as frequency converters, smart meters, and third-party PLCs-enabling stable bidirectional data exchange in automation setups. It supports multiple widely used industrial protocols, including Allen Bradley's proprietary DF1 (full-duplex/half-duplex) and DH-485 protocols, as well as the universal Modbus RTU protocol (in both client and server modes). This means it can seamlessly connect with Allen Bradley equipment and third-party devices, reducing compatibility issues in mixed-system environments.

The Allen Bradley 1734-485ASC has configurable data bits (7 or 8), stop bits (1, 1.5, or 2), and parity (none, even, or odd). The baud rates range from 1200 bps to 115200 bps. To reduce signal reflection and guarantee steady data transfer, the module has a single RS-485 differential port with A+, B-, and GND pins as well as an integrated 120Ω termination resistor that can be activated via a dip switch or software. It can accommodate up to 32 nodes on a bus without a repeater, and its transmission range is up to 1200 meters at 9600 bps (with shielded twisted-pair cable) and roughly 150 meters at 115200 bps.

The Allen Bradley 1734-485ASC is compatible with Allen Bradley's Logix series controllers, such as ControlLogix, CompactLogix, and FlexLogix, and mounts on a 35 mm standard DIN rail (requiring a Point I/O base). Studio 5000 Logix Designer software (version 24 or higher) is used for configuration, enabling online parameter changes without stopping the system. When combined with a hot-swappable base (such as the 1734-TB3H), it facilitates hot swapping for added convenience, allowing module replacement while the system is powered on to minimize downtime.

Specifications

Model	1734-485ASC
Series	Allen Bradley Point I/O Series
Module Type	RS-485 Serial Communication Converter Module
Certifications	UL, cUL, CE, ATEX, IEC 61010-1
Communication Interface	RS-485 Balanced Differential Serial Interface
Topology	Bus
Maximum Nodes	32
Dimensions (L × W × H)	118mm × 32mm × 110mm

Precautions

First, when installing the Allen Bradley 1734-485ASC, always use a compatible Point I/O base (such as 1734-TB, 1734-TB3, or 1734-TB3H). The power supply and signal transmission will be disrupted if the module is mounted directly on a 35mm DIN rail without the base. Make sure the base is firmly attached to the rail to avoid power problems or poor communication due to loose connections.

Carefully match the terminals when wiring the RS-485 port: connect the module's X (RS-485 A+) to the field devices' matching A+ terminal, Y (RS-485 B-) to B-, and G to signal ground (GND). Before turning on, double-check the wiring because switching A+ and B- will disrupt communication. For RS-485 connections, use shielded twisted-pair cable (such as Belden 9841) to reduce EMI; to prevent signal interference, keep the cable away from high-voltage lines and motor cables. Add an RS-485 repeater (like the Allen Bradley 1784-KTCX) to increase range and preserve signal quality for bus lengths longer than 150 meters (at high baud rates) or more than 32 nodes. Enable the built-in 120Ω termination resistor (via DIP switch or Studio 5000 software) when the module is at either end of the RS-485 bus-this reduces signal reflection and improves data transmission stability.

FAQ

Q: What is the Allen Bradley 1734-485ASC module used for?

A: The Allen-Bradley 1734-485ASC is a POINT I/O serial interface module that bridges RS-485 or RS-422 ASCII devices-such as barcode readers, weigh scales, vision sensors, serial printers, and serial displays-to a Logix controller within a distributed I/O architecture. It provides a single full-duplex serial communication channel operating at user-selectable baud rates from 300 bps to 38400 bps, enabling ASCII-based data transfer between peripheral devices and Rockwell Automation control systems.

Q: What baud rates does the 1734-485ASC support?

A: The 1734-485ASC supports selectable baud rates from 300 bps to 38400 bps, including the following standard rates: 300, 600, 1200, 2400, 4800, 9600, 19200, and 38400 bps.

Q: How much power does the 1734-485ASC consume?

A: The 1734-485ASC consumes 15 mA at a 24 V DC nominal power supply, with an operating voltage range of 10 V DC to 28.8 V DC. On the POINTBus backplane (5 V DC side), the module draws 75 mA. The maximum thermal dissipation is 0.75 W at 28.8 V DC, equivalent to 2.5 BTU/hour.

Q: What is the physical footprint of the module?

A: The 1734-485ASC measures 12 mm in width, 56 mm in height, and 75.5 mm in depth. It allows horizontal or vertical mounting with no de-rating required and supports Removal and Insertion Under Power (RIUP), enabling live module replacement without a system shutdown.

Q: How should I wire and install the 1734-485ASC module?

A: The 1734-485ASC connects to RS-485 or RS-422 networks via the removable terminal block (RTB)-specifically the 1734-TB or 1734-TBS wiring base assembly. For proper installation, insert the module into the POINT I/O rack, rotate the keyswitch on the mounting base to position 2, and wire network cables to the appropriate positions on the terminal block.