1771-DA

The 1771-DA PLC 5 ASCI I/O Module by Allen-Bradley is a module which allows for the transfer of data by means of an I/O scan from ASCII devices to a programmable controller processor data table with the expandable data table and block transferability. The 1771-DA provides an interface via the RS-232-C 200mA current loop and the A-B Long line and has a user selectable communication rates of 110, 300, 600, 1200, 2400, 4800, and 9600 Bauds. The 1771-DA is located on the I/O chassis of the 1771 Chassis, and it draws a backplane current of 1.3A. It has a buffer memory of 1.5K words and keying of the module is by connecting the top connector between pin 8 and 10 or between 30 and 32. The current loop uses a passive receiver circuit with 4-20mA input current range at a nominal voltage of 1.5-2.05V DC and a reverse voltage limit of 5V DC. The 1771-DA also uses the active transmitter circuit with an input rating of 23mA and a passive transmitter circuit with an input rating of 55mA current at 2.25 nominal voltage with a reverse voltage of 2.7V DC across pins 11 and 18. The current loop interface provides 500V DC voltage isolation between users and the programmable controller circuitry system. The RS-232-C has a receiver circuit control with a rating of 3-25V DC input voltage with an input impedance of 3-7 KiloOhms, and a transmitter circuit with a rating of 5-15V DC for space state and -5 to -15V DC for mark state and it also provides voltage isolation with the same parameters as the current loop interface.