Technical Specifications

Main Features and Advantages

The YOKOGAWA ALR121-S50 is distinguished by its primary function of providing redundant serial communication, which offers a significant advantage in mission-critical applications. When configured in a redundant pair, the two ALR121-S50 modules operate in an active-standby relationship, ensuring that if one unit fails, the other automatically takes over without any loss of data or communication. This active failover capability is crucial for maintaining the integrity of control loops that depend on data from third-party serial devices. The module also supports multiple serial protocols (RS-232, RS-422, RS-485) and offers software-configurable data transfer rates, providing a high degree of flexibility for integrating various types of equipment. Its deep integration with the CENTUM VP platform simplifies both configuration and maintenance, as all parameters can be managed through the standard CENTUM VP engineering tools. The dual-port design of the ALR121-S50 allows it to simultaneously communicate with two independent serial devices or to create a redundant link to a single device. Its robust on-board diagnostics and status LEDs provide immediate visual feedback on the health of the communication channels and the module’s operational status, which is vital for quick troubleshooting. The YOKOGAWA ALR121-S50 is a reliable solution for bridging the gap between the modern DCS and a vast range of legacy or specialized serial devices, ensuring data reliability and system uptime.

Application Field

The YOKOGAWA ALR121-S50 module is an indispensable component in industrial environments that require reliable serial communication for external devices, especially where redundancy is a key requirement. Its main applications are in industries such as oil and gas, petrochemicals, power generation, and pharmaceuticals. In these sectors, the ALR121-S50 is used to connect the CENTUM VP DCS to a variety of critical equipment, including gas chromatographs, analyzers, specialized instruments for quality control, and weighing systems. It is also found in manufacturing facilities that utilize robotics, CNC machines, or barcode readers that communicate via serial protocols. The redundancy offered by the ALR121-S50 is particularly valuable in these fields, where continuous data from analyzers or a constant link to a machine is essential to maintain product quality and safety. For example, in a chemical plant, a redundant pair of ALR121-S50 modules could be used to ensure a continuous connection to an on-line analyzer that provides critical feedback for a process control loop. The module’s support for different serial protocols makes it a versatile solution for integrating various devices, solving the challenge of connecting specialized or legacy equipment to a modern and robust control system.

Related Products

ALR121-S00: This is the standard, single-channel version of the ALR121. While it offers the same core serial communication functionality, it lacks the built-in redundancy of the ALR121-S50. ALP121-S50: This module is also designed for redundancy but for a different communication protocol, namely PROFIBUS-DP, highlighting a key difference from the serial-focused ALR121-S50. ALF111: This is a Foundation Fieldbus communication module for the CENTUM VP system, designed to connect devices using that protocol, serving a similar function but for a different network type than the ALR121-S50. AFV30S: The Field Control Unit (FCU) for the CENTUM VP system, which serves as the host for the ALR121-S50 module. ANB10: An ESB Bus Node Unit that can house the ALR121-S50 module, enabling the extension of serial communication from the main Field Control Unit. AGP81: A general-purpose communication gateway module that can be used for a variety of protocols, including serial, but is often used in different architectures than the in-chassis ALR121-S50.

Installation and Maintenance

Pre-installation preparation: Before installing a pair of YOKOGAWA ALR121-S50 modules, it is critical to ensure that the CENTUM VP Field Control Station (FCS) is fully de-energized to prevent damage. The system software, including CENTUM VP’s engineering tools, must be compatible with the modules’ firmware. When installing a redundant pair, place both ALR121-S50 modules in adjacent slots as specified in the manual. Prepare the necessary serial cables and ensure they are properly connected and configured for the correct protocol (RS-232, 422, or 485) and communication parameters (baud rate, parity, etc.).

Maintenance recommendations: Routine maintenance for the ALR121-S50 modules is primarily focused on software diagnostics and external device health checks. Use the CENTUM VP’s built-in monitoring functions to check the communication status and performance of the serial links. The on-board LED indicators on each ALR121-S50 module provide an immediate visual check of its operational status and any communication errors. In the event of a failure, the system will automatically switch to the standby unit, but the failed ALR121-S50 module must be replaced promptly to restore the full redundancy and ensure continued high availability. When replacing a module, follow the hot-swapping procedure as outlined in the manual to minimize system interruption. For physical care, use a soft, dry cloth to remove dust from the module’s exterior and avoid using liquid cleaners

 

 

Product Guarantee

Yokogawa’s commitment to quality and reliability is reinforced by the product guarantee for the ALR121-S50. Each ALR121-S50 module is manufactured to the highest standards, ensuring its performance and longevity in the most demanding industrial environments. The product is backed by a comprehensive warranty that covers manufacturing defects, providing customers with confidence in their investment. In addition to the standard warranty, customers have access to Yokogawa’s global network of expert technical support, which is available to assist with all aspects of the module’s operation, from initial installation and configuration to troubleshooting and system optimization. This commitment to robust after-sales service and technical expertise ensures that users can rely on the performance and durability of the ALR121-S50 to maintain the stability and efficiency of their mission-critical automation systems.