This item is AC500 series RS485 communication expansion module belonging to ABB AC500 PLC platform, manufactured according to IEC industrial standards and ABB global production specifications. It is a plug-in optional accessory specially designed for AC500 CPU to expand independent RS485 communication channel, adopting compact embedded installation structure which can be directly inserted into CPU dedicated option slot to enrich system communication capacity without occupying onboard native serial port resource.

3BDH is fixed internal material coding prefix for ABB AC500 series PLC relevant expansion accessories.000011 stands for exclusive part serial number inside ABB internal product catalog of this communication accessory.R1 represents first revised hardware version with optimized internal circuit compared with original prototype design.

The module gets working power from CPU internal backplane bus with no extra external power supply needed. Communication interface follows standard RS485 electrical specification, supporting maximum baud rate up to 115200bps and maximum transmission distance of 1200 meters under low baud rate condition. Working ambient temperature ranges from -25℃ to +60℃, storage temperature ranges from -40℃ to +85℃, protection grade is IP20 for inner cabinet installation. The whole product passes IEC61000 EMC anti-interference and industrial vibration test.

Front side is equipped with three-position screw type wiring terminal for RS485 A line, B line and ground connection to access field bus equipment. Rear side uses gold finger plugging structure to insert into CPU dedicated expansion slot and complete internal data interaction through CPU built-in bus. Built-in hardware circuit supports Modbus RTU master and slave mode, no integrated Ethernet or other fieldbus circuit on this module body.

Its core function is expanding an independent hardware RS485 communication channel for AC500 series CPU. It separates newly added communication link from original onboard serial port, realizing independent data exchange channel for external inverters, field transmitters and remote I/O modules via Modbus RTU protocol. It effectively avoids communication resource conflict caused by multiple field devices connecting to single original serial port and improves overall communication stability and system expandability of PLC control system.

It is commonly matched with AC500 series PLC in automation control cabinets of water treatment engineering, packaging production equipment, fan and pump centralized control, textile machinery and small building automatic monitoring system, used for accessing various RS485-type field intelligent instruments and drive devices.

Cut off the whole power supply of matched CPU before installation, insert the expansion module vertically into designated option slot until mechanical locking is finished. Complete field bus wiring strictly complying with terminal polarity definition of A, B and ground, and configure terminal matching resistor at bus terminal end based on actual cable length. Carry out regular maintenance every six months, remove dust on circuit and terminals with dry soft brush and forbid liquid cleaning agent. Replace the complete module once continuous communication fault exists after eliminating external wiring problems, unauthorized disassembly and internal circuit modification are prohibited.