Product Details
Product Overview
The Yokogawa ALR121-S50 functions as a core serial communication module for the CENTUM integrated production control system. It provides two independent channels for RS-422 or RS-485 serial data exchange, connecting external subsystems such as PLCs, analyzers, or power meters to the field control station. We supply this module as 100% Brand New and Original, ensuring optimal data throughput and integration integrity for your control architecture.
Part Number Breakdown
| Code | Specification | Description |
| ALR121 | Model | Serial Communication Module (RS-422/RS-485, 2 ports) |
| -S | Type | Standard Type |
| 5 | Protection | With no explosion protection |
| 0 | Version | Basic type hardware revision |
Technical Specifications
| Feature | Specification |
| Interface | RS-422/RS-485 |
| Communication Mode | Half-duplex |
| Transmission Speed | 1200 to 38400 bps |
| Synchronization | Start-stop synchronization |
| Code Structure | ASCII / Binary |
| Current Consumption | 0.5 A |
| Dimensions | 3.28 cm x 14.29 cm x 13 cm |
| Weight | 0.3 kg |
Engineering Advantages
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Flexible Topology: The module supports point-to-point connections for RS-422 and multipoint daisy-chain configurations for RS-485. This versatility allows engineers to deploy multiple field devices on a single physical bus, reducing cabling complexity.
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Variable Baud Rate Control: Users select from a broad range of transmission speeds (up to 38400 bps), allowing precise matching with the latency requirements of legacy third-party subsystems.
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Compact Physical Footprint: The module measures only 3.28 cm in width, optimizing valuable cabinet space in high-density rack environments. Its slim design promotes better airflow around adjacent I/O modules, preventing localized hot spots.
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Simplified Integration: The module utilizes standard start-stop synchronization, ensuring seamless handshake protocols with most industrial sensors and actuators without requiring custom middleware.
FAQs
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Can I connect both RS-422 and RS-485 devices simultaneously?
Yes. The two ports operate independently. You can configure one port for a point-to-point RS-422 link and the second port for an RS-485 multipoint network, provided you respect the software configuration constraints for each channel.
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What is the maximum distance for the RS-485 connection?
Standard RS-485 physical layer specifications support distances up to 1200 meters. However, we recommend high-quality twisted-pair shielded cabling to maintain signal integrity at these maximum ranges in electrically noisy environments.
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Does this unit require special firmware for older CENTUM systems?
The ALR121-S50 serves as a standard hardware component. Most CENTUM system software versions recognize this unit automatically; however, always verify your FCS configuration and software revision compatibility in the system engineering manual before commissioning.
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What causes communication errors with this module?
Most errors stem from improper termination resistors on the RS-485 bus or baud rate mismatches. Verify your parity settings and termination jumpers at both ends of the transmission line to ensure stable data flow.
Additional Information
- 100% Genuine Parts: All products are original and authentic, ensuring reliable industrial performance.
- 30-Day Refund Guarantee: Return any in-stock item within 30 days in original, unopened packaging for a full refund (excluding shipping and fees).
- 12-Month Warranty: Covers defects in materials or workmanship; excludes misuse, normal wear, or unauthorized modifications.
- Worldwide Shipping: We ship via USPS, UPS, FedEx, and DHL. Delivery times vary by country and may be subject to customs or import fees.
- Support & Contact: Technical and warranty assistance is available anytime. Contact us here: Contact.
- Purchase Guidance: Check product specifications and compatibility carefully before ordering to ensure proper application.
Tech & Buying Guide
Understanding Marshalling Cabinets in Industrial Control Systems Architecture
Industrial control system deployments rely on structured signal distribution to bridge field instrumentation with central processing hardware. A marshalling cabinet serves as the vital intermediate connection point between heavy field home-run multi-pair cables and delicate input/output (I/O) modules housed inside Programmable Logic Controller (PLC) or Distributed Control System (DCS) enclosures. By segregating field cable terminations from control hardware, engineers maintain system flexibility, safeguard controller components, and streamline commissioning workflows.
FAT vs SAT in Industrial Control Systems: Key Differences and Execution Guide
Industrial control system deployment relies on strict verification protocols to guarantee operational safety, system stability, and regulatory compliance. Commissioning complex Programmable Logic Controller (PLC) racks, Distributed Control Systems (DCS), and Safety Instrumented Systems (SIS) requires two critical milestones: the Factory Acceptance Test (FAT) and the Site Acceptance Test (SAT). Both procedures validate that system automation meets design specifications, but they occur at different stages of project execution and target distinct operational risks.
Hub vs Switch vs Router in Industrial Automation Architecture
Modern factory automation relies on reliable industrial networking infrastructure to exchange real-time field data across operational technology systems. Engineers often encounter networking hardware like hubs, switches, and routers when integrating Programmable Logic Controllers, Distributed Control Systems, and SCADA monitoring nodes. Although these devices share physical ports, they operate at different layers of the Open Systems Interconnection reference model and deliver distinct traffic management capabilities.