4-port, RS-232/422/485 serial communications board

The DNx-SL-501 are 4-port serial communications layers for UEI’s powerful Cube, RACKtangle and FLATRACK I/O chassis. The boards offer fully isolated serial interfaces, software-configurable as RS-232 or RS-485.
DNx-SL-501 supports up to 2 Mb/s transfer speed in RS-485 mode or up to 256 Kb/s in RS-232 mode. A special version of the board, designated as the DNx-SL-501-804, supports baud rates up to 4 Mb/s. The boards use a 16550C UART emulation on each port (FIFO mode only) and support half- and full-duplex mode over RS-485.

The DNx-SL-501-804 is compatible with RS-422 networks when used in RS-485 mode. The layer provides 200 Ω software-selectable TX and/or RX termination for RS-485 communications. The DNx-SL-501-804 is an ideal solution for connecting serial based data acquisition devices to the Ethernet, as well as interfacing to a wide variety of serial based devices and legacy DAQ systems. In addition to standard serial I/O features, the DNx-SL-501-804 offers a series of additional functions. These functions include:

• Fully customizable baud rates, generated by programmable PLL on per-channel basis from 300 baud to 4 Mbaud
• Programmable inter-character delay (required to drive/simulate some avionics instruments)
• Programmable inter-frame delay (used to schedule frames at different rate)
• Automatic repeat of the last frame if new data is not sent from the host on time (required to keep "inop" flag happy on many avionics devices)
• None/Even/Odd/Space/Mark parity in 8-bit mode and per- symbol programmable in 9-bit mode
• Automatic in-hardware or software flow control
• Asynchronous event mode with loop closure in 100 μs (for avionics expecting immediate reply)
• Echo suppression in half-duplex mode (for 422 mode)
• Timeout programmable in 10us, 100us or 1ms intervals

Software is included, providing a comprehensive, yet easy-to-use API that supports all popular operating systems, including Windows, Linux, and most real-time operating systems—such as QNX, Intime, VXworks, and more. Additionally, the UEIDAQ Framework—an even higher level Windows driver—supplies complete support for those creating applications in many popular Windows programming languages, as well as data acquisition software packages such as LabVIEW and MATLAB/Simulink.

Finally, the DNx-SL-501 includes the UEI-RSS remote serial server. The RSS allows the SL-501 slots to be configured as standard “Com” ports in both Windows and Linux environments.