Product Description
The ALR121-S51 S1 is a high-reliability serial communication interface module designed for integration with Yokogawa CENTUM VP and Yokogawa CENTUM CS 3000 Distributed Control Systems (DCS). It acts as a communication bridge between the Field Control Station (FCS) and external industrial devices such as PLC networks, power monitoring systems, and motor controllers.
The module supports both RS-422 and RS-485 physical layers, enabling flexible network topologies including point-to-point and multi-drop bus configurations.
Engineered in Japan for long-term reliability, the ALR121-S51 S1 features asynchronous half-duplex communication, electrical isolation to prevent ground loop interference, and high-density installation compatibility within Yokogawa node units. Its hot-swappable design allows maintenance without disrupting primary control operations.
Technical Specifications
| Parameter | Specification |
|---|---|
| Model | ALR121-S51 S1 |
| Communication Interface | Dual RS-422 / RS-485 ports |
| Transmission Mode | Asynchronous, half-duplex |
| Baud Rate | 1200 – 38400 bps |
| Maximum Cable Distance | 1200 m (total bus length) |
| Data Format | 7 or 8 data bits |
| Stop Bits | 1 or 2 |
| Error Checking | None / Even / Odd parity |
| Protocol Support | Modbus-RTU, proprietary subsystem protocols |
| Operating Current | 0.5 A at 5V DC (internal bus) |
| Dimensions | 77 × 42 × 106 mm |
| Weight | 0.2 kg |
Application
The ALR121-S51 S1 is widely used in industrial monitoring and control systems such as:
-
Energy management systems
-
Water treatment plant automation
-
Variable Frequency Drive (VFD) monitoring
-
Industrial sensor telemetry networks
It is commonly used to connect Yokogawa controllers to third-party devices requiring Modbus-RTU communication for real-time data acquisition and control.
FAQ
Q1: What is the difference between S51 and S53 variants?
The S51 variant represents standard CENTUM VP specifications, while S53 may indicate specialized environmental protection coatings or legacy hardware revisions.
Q2: Does this module support redundancy?
Yes. When installed in redundant node units, two ALR121-S51 S1 modules can operate in failover configurations to ensure communication continuity.
Q3: Can communication parameters be configured via software?
Yes. Baud rate, parity, and other port parameters are configurable through the Yokogawa System View configuration environment.
| Quick Quotes | Receive price & availability FAST from our dedicated customer service team. |
|---|---|
| Delivery | Expedited, Freight, And International Shipping Available. |
| Condition | 100% New with Original Package |
| Payment | We accept American Express, Discover, MasterCard, PayPal, and Visa. Our site is secured by RapidSSL. |
| Shipping Port | ShangHai, Xiamen |
| Warranty | 12 Months |
| Q: Is Our Pricing Competitive? |
| A: Yes, we collaborate with over 50 countries worldwide. As a top supplier in China, we offer significant discounts based on market trends. |
| Q: What Is the Warranty Period? |
| A: All our new and original products come with a standard one-year warranty. |
| Q: What Payment Methods Do We Accept? |
| A: We require 100% T/T (Telegraphic Transfer) payment before shipping. For items with a lead time, a 30% deposit is needed upfront, and the remaining 70% is due before shipping. If you have a representative in China, you can arrange an RMB transfer through them. |
| Q: What Shipping Methods Do We Use? |
| A: We primarily use FedEx, DHL, UPS, and BRE for shipping. If you have an account with any of these carriers, you can handle shipping directly. We also offer free shipping to China-based freight forwarders. |
| Q: What Is Our Delivery Time? |
| A: Delivery usually takes 1-3 days after receiving the initial payment. For items with a lead time, shipping will occur according to the specified schedule. |
| Q: How Do We Package the Goods? |
| A: We ensure safe packaging with multiple layers of protection. Products are first placed in their original boxes and sealed with labels. A layer of bubble wrap is then added for collision protection during transit. Finally, the items are packed securely in durable boxes. |
| Q: How Can Customers Contact Us and Request a Quote? |
| A: You can reach out to us via email, WhatsApp, WeChat, Skype, or your preferred communication platform. Contact us with your needs, and we'll provide a prompt, customized quote. |
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