National Instruments PXIe-8431/8 PXI Serial Interface Module with 8 Ports Full Duplex Transmission for RS485/RS422 Standards

• 8-port serial interface module supporting RS485/RS422 standards
• Full-duplex transmission capability
• Master-slave communication architecture
• Modbus communication protocol support
• Compatible with both serial communication (RS-485, RS-422) and TCP/IP networks (Modbus TCP)
• Supports systems with one master device and up to 247 slave devices

The PXIe-8431/8 module implements a master-slave communication model where one device serves as the Master and others as Slaves. Communication occurs exclusively between the Master and Slaves, with no direct data exchange between slaves.

The RS-422 standard typically uses 4-wire shielded twisted pair cable, allowing connections between one device and another (supporting up to 5 controllers and 10 receivers per controller). In most implementations, the RS-422 controller serves as the master while RS-485 devices function as slaves to optimize system performance.

The module supports Modbus, a client-server architecture communication standard commonly used in industrial automation for connecting electrical devices. The PXIe-8431/8 features two transmission modes that describe unique data structures within messages for information transfer, ensuring consistent communication with slave devices.