1791-8BC

The 1791-8BC is a Combination discrete input and output module from the Block I/O series of Allen-Bradley. This module is ideally used to implement distributed I/O architecture as it comes with a rackless design and supports DIN rail mounting. This module is compatible for use with Allen-Bradley’s PLC-2, PLC-3, 1785 PLC-5 series, 1747 SLC 500 Series, Logix automation platforms such as CompactLogix and ControlLogix controllers via a Remote I/O (RIO) communication module. The 1791-8BC communicates with partner controllers via Remote IO (RIO) communication protocol via 1771-CD or Belden 9463 3-wire communication cable at transmission rates of 57.6K and 115.2K baud and 230.4K baud. This RIO communication capability is available via terminals 6 (BLU), 7 (SHD), and 8 (CLR). The RIO network's first and last node must be terminated with a terminating resistor with values 150 Ohms at 57.6K and 115.2K baud rates and 82 Ohms at 230.4K baud. This terminating resistor is connected across 6 (BLU) and 8 (CLR) terminals. This module has Eight (8) 24 VDC discrete inputs arranged in a single group. An input voltage range of 10-30 VDC can be applied to the input terminals along with a minimum On-state current of 2.5 mA at 10 VDC and a maximum input current of 11.0 mA at 30 VDC. This module also has Eight (8) 24 VDC Discrete outputs with a voltage output range of 10-30 VDC. Each output current rating varies according to the mounting orientation and ambient temperature specifically, 500mA @ 60oC, 1A @ 30oC in vertical mounting and 250mA @ 60oC, 500mA @ 30oC in horizontal mounting. This module is externally powered by a 19.2-30 VDC supply voltage along a 300 mA input current.

The Allen-Bradley 1791-8BC is an 8 points DC block I/O module. This module has eight inputs and outputs. The 1791-8BC uses DC as the main power and also as the base for power to be delivered. Both the output and input voltage range is between 10 to 30 Volts DC. The range of the on-state current for this module is the same as any other typical DC I/O module on the 1791 series. The range of on-state current is 2.5 to 11 milliamps at 10 to 30 Volts. This module has an output current rating of 500 milliamps at 60 degrees Celsius in vertical mounting. This module only has internal protection that protects the current that comes in. The 1791-8BC has fewer inputs and outputs compared to other types within the 1791 series. Thus, the power and thermal dissipation of this module are also quite small. The amount of power and thermal dissipation of this module is 11.8 watts and 41 BTU/hour. The suitable wire size for this module is 14 gauge stranded maximum wire with 3/64 inch maximum.