The YOKOGAWA ALR111 is a high-performance serial communication module designed for point-to-point data exchange within CENTUM VP control systems. It acts as a dedicated interface for integrating third-party serial devices, such as analyzers, programmable logic controllers (PLCs), and operator interfaces, directly into the DCS network.

Key Hardware & Connectivity Specifications

Communication and Transmission Characteristics

The ALR111 provides reliable serial communication for devices located within a 15-meter range. It supports flexible data formatting, including selectable character lengths (7/8 bits), stop bits (1/2 bits), and parity (none/even/odd), allowing for broad compatibility with diverse industrial communication protocols. The module is specifically optimized for efficient data polling and event-driven communication with a strictly defined lag time of 1 ms after data transmission to maintain loop timing integrity.

Integration and Installation

The ALR111 is designed for modular installation, compatible with a variety of Yokogawa field units, including the ANB10, ANB11, ANR10, AFF50, and AFV series (AFV10/30/40). To maintain signal integrity and meet electromagnetic compatibility standards, Yokogawa recommends specific cabling assemblies:

• Standard Wiring: Compatible with AKB131, AKB132, AKB133, and AKB134 cable series.
• Shielded Requirements: For environments with high electrical noise, 3-pair shielded cables (AKB161 or AKB162) should be utilized to protect signal fidelity.

Frequently Asked Questions

Q: How does the ALR111 differ from the ALR121?

A: While both are serial communication modules, the ALR111 is strictly limited to RS-232C point-to-point communication. The ALR121 provides additional support for RS-422/RS-485 interfaces, allowing for both point-to-point and multipoint communication over much longer distances (up to 1200 meters).

Q: Is the ALR111 capable of full-duplex communication?

A: No. The ALR111 module is designed for half-duplex communication, meaning data can be transmitted and received, but not simultaneously on the same channel.

Field Installation Guidelines

1. Ensure the control station power is de-energized before mounting the ALR111 into the target unit (e.g., AFV40 or ANB11).
2. Use the appropriate AKB series cable for the specific terminal unit to ensure proper impedance matching and connector seating.
3. Terminate the cable shield at the designated cabinet grounding rail to prevent common-mode noise from affecting serial data packets.
4. Verify the communication settings (baud rate, parity, stop bits) on the external device exactly match the configuration assigned in the CENTUM VP software.
5. Once powered, monitor the module status via the engineering station to confirm the link status and clear any initial framing errors.