Product Description:

The 5A1102.00-090 is an expansion module from B&R Automation's 5A1 PLC Addon Boards series. It adds two serial channels to a controller rack so barcode scanners, operator terminals, and other legacy devices can be connected without using a main CPU interface. This approach leaves the primary controller connections free for other network or motion tasks. By occupying a single PLC slot, the card extends communication through the host backplane bus while keeping the installation compact inside an automated system.

The board connects through a 16-bit ISA interface and provides two independent RS-232 ports. Port resources are selected with configuration jumpers, and the factory default maps the lower and upper interfaces to COM3/COM4. An interface count of 2 allows each channel to be addressed separately by the operating system, which is useful when different peripheral types must run at the same time. Input signals include DCD, RXD, DSR, CTS, and RI, while output lines include TXD, DTR, and RTS for full modem-control capability. This signal set supports straightforward connection of equipment that relies on standard serial handshaking rather than simplified transmit-and-receive wiring alone.

The serial channels are galvanically isolated from the CPU subsystem, and pin 5 on each connector supplies a signal ground that is isolated from chassis ground to help limit earth-loop current. Installation is possible in a short slot, which helps conserve rack space in compact control cabinets where card length can restrict module selection. Hardware interrupts can be selected from 3, 4, 5, 7, 10, 11 to avoid conflicts with other ISA cards already present in the rack. Each channel includes 4 front-panel LEDs that indicate transmit, receive, and modem status during operation. These indicators provide immediate visual feedback when checking line activity or handshake response at the module face.