1791D-8B8P

The 1791D-8B8P is manufactured by Allen Bradley, Rockwell Automation. It is a CompactBlock I/O module containing a built-in power supply, a DeviceNet I/O adapter and various I/O circuits. It belongs to the 1791D CompactBlock family of devices and is a base module containing 8 sinking inputs and 8 sourcing outputs. The size of the device enables it to be used in a close range of any sensor or actuator in a constrained space with many distributed I/O blocks. The 1791D-8B8P features a built-in 10 to 30 Volt DC power source that helps the device adapt to a broad range of power supplies and voltage levels from the network and a NEMA Type 1+ input that allows the device to be compatible to different sensors. A communication rate of maximum 500 Kbps is achievable up to a distance of 100 meters using this device, and to protect against accidental incorrect wiring, a feature is provided to prevent the output from short-circuiting. To prevent the module from crashing due to wrong baud rates, an automatic baud detection system is also provided. Because of how compact this device is, it could be used close up to an actuator or a sensor, which also lowers the cost of wiring. Any master PLC, SLC, or SoftLogix Controller can be connected via this device. In such a master/slave condition, this device acts as a slave.

Being highly compact in nature, no additional power supply or adapter is required for this device. However, for the inputs and outputs, use an independent 24 Volt DC supply. Options are available in the device to choose between three different communications modes, which are polled, cyclic and change-of-state. This I/O module could be mounted both vertically and horizontally on either a DIN rail or an enclosed panel; however, the user should ensure that the operating temperatures remain between 0 and 60 degrees Celsius. For this module’s wire connections, use 14 gauge stranded wire which has an insulation of at least 3.64 inches.