The Allen-Bradley 1734-APB is a point I/O PROFIBUS adapter module in the Bulletin 1734 POINT I/O™ series.  It simultaneously resides on the POINT I/O backplane (PointBus) and the PROFIBUS network. This position allows the adapter to interface between the POINT I/O modules and the PROFIBUS network. On the PointBus, it functions as a master unit and communicates with up to 63 POINT I/O modules. While on the PROFIBUS, it serves as a slave unit and it works by exchanging I/O data with the PROFIBUS master. The 1734-APB adapter module has an input voltage rating of 24 Volts DC nominal, a 10 to 28.8 Volts DC range. and Its inrush current is 6 Amps maximum for 10 milliseconds, with a PointBus output current of 1 Amp maximum at 5 Volts DC ±5% (4.75 to 5.25).

The 1734-APB features a reverse polarity protection for input overvoltage. And in case of interruptions or when input drops out, the output voltage stays within specifications for 10ms at 10V with maximum load. The POINT I/O 1734-APB adapter is installed at the left side of a 1734 system. It converts the applied 12 to 24 Volts DC field power to PointBus 5 Volts power to supply 5 Volts logic power to the POINT I/O modules. It can cater to a total expansion of up to 63 modules maximum connection.  It can power up to 14 I/O modules with a maximum of 10 Amps of field power, with 75mA current draw. To comply with CE Low Voltage Directives (LVD), a Safety Extra Low Voltage (SELV), an NE Class 2, or a Protected Extra Low Voltage (PELV) power supply can be used.