Product Overview
When modernizing a PROFIBUS DP network in a legacy plant, the Allen-Bradley 1734-APB provides a direct, high-reliability bridge between your PROFIBUS master and POINT I/O modules. This adapter is part of the Bulletin 1734 POINT I/O series and simultaneously resides on the PointBus backplane and the PROFIBUS network, functioning as a master on the PointBus (supporting up to 63 I/O modules) and as a slave on PROFIBUS. With a nominal input voltage of 24 Volts DC and a field-side power rating of 400 milliamps, the 1734-APB is built for demanding industrial environments.
Technical Specifications
Key parameters extracted from the product datasheet:
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Input Voltage: 24 Volts DC (nominal), range 10–28.8V DC
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Field Side Power: 400 milliamps
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Inrush Current: 6 amps (10 ms maximum)
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POINTBus Current: 1000 milliamps at 5V DC
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Power Consumption: 8 Watts
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Power Dissipation: 2.8 Watts at 28.8V
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Input Protection: Reverse polarity protection, output holds for 10 ms at 10V with max load
These specifications ensure stable logic power delivery to up to 14 POINT I/O modules, with a maximum of 10 Amps field power available.
Industry Applications
The 1734-APB is ideal for upgrading aging distributed control systems (DCS) that rely on PROFIBUS DP. In a chemical processing plant, for instance, replacing a legacy gateway with this adapter reduces wiring complexity and increases data throughput. The adapter’s robust overvoltage protection and inrush handling make it suitable for motor control centers and conveyor systems where power fluctuations are common.
Installation & Setup Guidance
Mount the 1734-APB at the leftmost position of the POINT I/O chassis. Connect the PROFIBUS DP cable to the DB-9 connector and set the node address via rotary switches. Apply 24V DC from a Safety Extra Low Voltage (SELV) or Class 2 power supply. The adapter automatically powers the PointBus and supplies 5V logic to connected I/O modules. For CE compliance, use a PELV supply. Ensure the PROFIBUS master is configured with the correct GSD file (available from Rockwell Automation).
Compatibility & Integration
The 1734-APB integrates seamlessly with Rockwell Automation’s ControlLogix and CompactLogix controllers via a PROFIBUS master module. It also works with any third-party PROFIBUS DP master (e.g., Siemens S7-300/400). The PointBus interface allows direct connection to over 60 different POINT I/O modules, including digital, analog, and specialty modules. No external power supply is needed for the bus – the adapter converts field power to the required 5V logic.
Selection Guide & Purchasing Advice
Before purchasing, verify that your PROFIBUS network’s baud rate (up to 12 Mbaud) and station address are compatible. The adapter requires a 24V DC power source with at least 6A inrush capability. For complete system integration, order the matching termination resistors and PROFIBUS connectors. UBEST Automation stocks the Allen-Bradley 1734-APB as a genuine new/replacement unit. Visit ubest101 for pricing and availability.