SM902A HollySys Power Module, Shanghai Sijian Intelligent Technology Co., Ltd. is engaged in technical development, technical consultation, technical transfer, sales of electrical equipment, automation equipment, electronic products, communication products, and electromechanical products in the fields of intelligent technology, information technology, and automation technology. Industrial automation products: PLC, DCS, sensors, frequency converters, encoders, relays, servo drives, soft starters, touch screens. Brands involved in the products include: Eurotherm, Schneider, Siemens, ABB, SICK, P+F, E+H, Yokogawa, Yamakawa, Mitsubishi, Emerson, Honeywell, FANUC, GE, Eaton Electrical, CT. SM902A_SM900_SM913 HollySys Power is a 24V/5V dual-channel isolated output power module in the SM series hardware products, and it is used in the power module slot of the M130/SM131 series cage.

SM902A HollySys Power Module, SM902A_SM900_SM913 HollySys Power. To improve system reliability, the SM902A power module can be configured in redundant pairs for parallel operation to handle faults. In 1+1 parallel operation, if any one power module fails, it can be replaced. After installing a new power module, the load is automatically redistributed. SM902A_SM900_SM913 HollySys Power achieves uninterrupted power supply switching and powers the main control module and I/O modules in the SM902A_SM900_SM913 HollySys Power cage.
It connects to the cage backplane via a pass-through connector, providing direct 24VDC output and converting 24VDC to 5.1VDC output. The input and output are isolated, and the two output channels are also isolated from each other. The SM902A adopts a modular design with an overall box-type plug-in structure, installed on the cage rail and secured with a latch. The SM900 power module uses 220VAC input. After EMI suppression and rectification filtering, it is divided into two isolated output channels, each with independent working circuits. SM902A_SM900_SM913 HollySys Power also features current sharing and redundancy functions for each channel. The AC input circuit of the SM900 power module is responsible for input rectification and filtering of the switching power supply, suppressing electromagnetic interference from the grid, and also suppressing electromagnetic interference generated by the power supply itself to ensure the AC input is free from electromagnetic pollution. After rectification and filtering, it outputs 24.5VDC and 5.1VDC respectively, and indicates the working status of the SM900 power module through an indicator circuit. The two output channels are directly provided to the backplane to power various modules on the backplane and field devices. SM902A_SM900_SM913 HollySys Power module block diagram.
It is used to store the system operating program (monitoring program), modular application function subroutines, command interpretation function subroutines, call management programs, and corresponding definitions (I/O, internal relays, timers, counters, shift registers, and other storage system) parameters, among other functions.
It is used to store the user program, i.e., the user program input via the programmer. The user memory of DCS is usually expressed in words (16 bits/word) to indicate storage capacity. At the same time, since the system program mentioned earlier is directly related to the performance of the DCS and cannot be directly accessed by the user, the memory type or storage method and capacity referred to in DCS product materials typically pertain to the user program memory.