1791DS-IB8XOB8

Features:

• Safety I/O Module with Eight Inputs and Eight Solid State Outputs for DeviceNet Networks
• Embedded Self-Diagnostics and Comprehensive I/O Status Monitoring
• SIL 3 Capable Design Compliant with IEC 61508 and EN 954-1 Category 4

The Allen-Bradley 1791DS-IB8XOB8 functions as a Guard I/O DeviceNet Safety Module, providing reliable safety input processing and solid state output control within industrial automation systems. It continuously manages eight safety input signals, eight solid state safety outputs, and four test outputs to support safety-critical operations in manufacturing lines, robotic cells, and process control environments. The 1791DS-IB8XOB8 operates with a 20.4 to 26.4 Volts DC I/O power supply voltage at a nominal 24 Volts DC, while the communications power supply requires 11 to 25 Volts DC, with a current consumption of 110 mA at 24 Volts DC. The module distributes I/O power and communication signals through the DeviceNet network to support steady state operation of all connected safety devices, and incorporates individual status indicators for each I/O point to provide immediate visual feedback on channel states.

The 1791DS-IB8XOB8 provides essential safety I/O functions common to the entire guard network, and is a critical component of the safety path, directly affecting the proper, normal operation of the overall safety monitoring system. One 1791DS-IB8XOB8 module is required per safety node depending on the desired I/O configuration. The 1791DS-IB8XOB8 occupies a compact form factor with an IP20-rated enclosure and is always mounted on 35 mm DIN rail within the control panel, requiring at least 50 mm clearance above and below for adequate ventilation and wiring room. The module includes a configuration lock feature to prevent unauthorized parameter changes and ensure operational security.

For safety input applications, the 1791DS-IB8XOB8 module processes eight current sinking safety inputs with a minimum on-state voltage of 11 Volts DC and an input current of 6 mA, with a maximum off-state input voltage of 5 Volts DC and a maximum off-state current of 1 mA. In addition to standard input operation, the 1791DS-IB8XOB8 also manages four current sourcing test outputs and eight current sourcing solid state safety outputs. The test outputs provide a rated output current of 0.7 Amps with a maximum residual voltage of 1.2 Volts and a maximum leakage current of 0.1 mA. The solid state safety outputs deliver a rated output current of 0.5 Amps with the same maximum residual voltage of 1.2 Volts and maximum leakage current of 0.1 mA. Using the integrated self-diagnostic functions, the 1791DS-IB8XOB8 continually monitors the health of all I/O points. If the system detects abnormal conditions in any input or output channel, it reports the status through individual point status indicators and places the corresponding status data in the I/O status registers, including Individual Point Input Status, Combined Input Status, Individual Point Output Status, Combined Output Status, Individual Test Output Status, and Individual Output Readback indicating the actual ON/OFF state of the outputs.