Yokogawa ALR111-S01 Serial Communication Module

The Yokogawa ALR111-S01, also cataloged as the ALR111 Serial Communication Module, operates as a dedicated hardware component for localized subsystem data integration and RS-232C protocol conversion within CENTUM VP and CS 3000 distributed control system (DCS) platforms.

Hardware Specifications

Process Control System Specifications

• 4-20 mA HART Loop Protocol Network Arbitration While executing dedicated serial transactions over RS-232C physical lines, the module bridges field subsystems—such as programmable logic controllers (PLCs), power monitors, and gas chromatographs—directly into the primary DCS architecture. It maps external variables into internal system register blocks, allowing digital instrumentation values to coordinate with central 4-20 mA regulatory control loops.
• Deterministic Processor Offloading and Channel Isolation The module incorporates an independent internal processor to manage the serial protocol stacks (including Modbus RTU and user-defined ASCII configurations). This architecture prevents high-frequency communication polling routines or sub-network data parsing from introducing latency or scan-cycle jitter into the Field Control Unit (FCU) core control logic.

Frequently Asked Questions

Q: How does the ALR111-S01 handle module-level hardware redundancy within the I/O node?

A: The module supports fully redundant duplex configurations. When two ALR111-S01 units are installed in paired slots, the standby module mirrors active protocol states and control registers, enabling an automatic bump-less transfer of communication loops if the primary unit encounters a hardware fault.

Q: Can the serial communication parameters be altered independently for each of the two physical ports?

A: Yes. The CENTUM system engineering software allows for separate configurations of baud rate (300 bps to 115.2 kbps), parity, stop bits, and data protocols on each D-sub 9-pin interface, allowing two dissimilar third-party devices to operate simultaneously.