Allen Bradley 1756-PA72

The Allen Bradley 1756-PA72 power module provided by Hanyite is a Rockwell Automation ControlLogix series power module and is part of the ControlLogix power module product line. It is mainly used in conjunction with the 1756 cabinet, providing 1.2V, 3.3V, 5V and 24V DC power supplies for the cabinet backboard. It is installed on the left side of the rack and directly inserted into the back plate. The choice of modules will affect the selection of rack types.

Power module technical specifications

The input voltage of Allen Bradley 1756-PA72 is 120/240V alternating current, and the operating voltage range is 85-265V alternating current. The input power is 100VA/100W. The input frequency is 47-63Hz. The module can provide 1.2V, 3.3V, 5V and 24V DC power supplies. When the current capacity is 1.2VDC, it is 1.5A. The rated power is 25W (operating temperature range 0 to 60℃), and the rated energy consumption is 85.3 BTU/ hour. The maximum surge current is 20A. The maximum current is 15A and the maximum transformer load is 100VA. Continuous voltage isolation is 250V; The reinforced insulation type transformer has passed the 3500VDC 60-second withstand voltage test.

Troubleshooting Common Faults

The power output of Allen Bradley 1756-PA72 is abnormal. It is manifested as abnormal module indicator lights (such as no power indicator light or constantly lit alarm light), which may cause downstream equipment to shut down or restart. Check whether the input voltage is within the rated range and whether the output is overloaded and has no short circuit. If the module loses communication with the main controller, it might be due to a loose communication interface or a fault in the optical isolation circuit. Diagnosis can be made through the 9600 Baud RS-232 interface (25-pin male type d connector). The module is equipped with an internal fault detection circuit that can continuously monitor the power rail, voltage regulator and internal busbar. When a transient fault occurs, the fault code can be read through the Diagread diagnostic tool. For permanent faults, the status of the hardware majority voting circuit must be checked.

Troubleshooting and Steps

Confirm that the Allen Bradley 1756-PA72 module to be replaced has been inserted into the physical slot and that the dual power rails are connected correctly. Measure the stability of the input voltage to rule out grid fluctuations or loose connections. Connect to the Diagread software via the Triconex diagnostic interface (RS-232) to read the logs of memory access and communication bus status. If "Communication Processor Fault" is displayed, please check the operating status of the MOTOROLA MPC860 processor (32-bit, 50MHz) and the integrity of the Flash ROM data. When a permanent fault is diagnosed, it supports online module replacement, and the system automatically switches to fault-tolerant mode (relying on fault detection circuits and redundant design). Please back up the configuration data before replacement to ensure that the firmware version of the replaced module is compatible with the original system.

 After-sales 

We offer a 24/7 technical hotline, free parts replacement service within the two-year warranty period, and customized program development support. Please feel free to contact us with any questions. For purchasing, please identify Hanyite in China.