Product Core Brief
- Model: ALR121-S50
- Brand: YOKOGAWA
- Series: CENTUM CS 3000 Serial Communication Module
- Core Function: 2-port RS-422/RS-485 serial communication module for CENTUM CS 3000 FCS.
- Product Type: DCS Serial Communication Module
- Key Specs: RS-422/RS-485 | 2 ports | 1200–115.2 kbps | ASCII/binary | Non-explosion-proof | Basic type | Max 6 per FCU, 3 pairs if redundant
- Condition: New Original (New Surplus) / Factory Sealed
Product Introduction
Serial communication cards are often the first place to check when a DCS loses contact with third-party devices. The is a YOKOGAWA CENTUM CS 3000 serial communication module, providing two RS-422/RS-485 ports for connecting external instruments, PLCs, analyzers, and serial devices.
The S50 suffix indicates the standard, non-explosion-proof, basic-type variant. This makes it a practical OEM replacement for existing ALR121 cards when the application requires RS-422/RS-485 communication without explosion-proof certification. For maintenance teams, it is commonly used in Modbus-RTU integration, serial device polling, and cross-system communication within CENTUM CS 3000 environments.
Key Technical Specifications
| Parameter | Value |
|---|---|
| Full Model | |
| Product Type | Serial Communication Module |
| Compatible System | YOKOGAWA CENTUM CS 3000 DCS |
| Interface | RS-422 / RS-485 |
| Ports | 2 ports |
| Connection Method | Point-to-point (RS-422), Multipoint (RS-485) |
| Communication Function | Half-duplex |
| Transmission Speed | 1200 / 2400 / 4800 / 9600 / 19200 / 38400 bps (up to 115.2 kbps depending on configuration) |
| Transmission Code | ASCII / Binary |
| Character Length | 7 / 8 bits |
| Stop Bit | 1 / 2 bits |
| Parity | None / Even / Odd |
| Transmission Distance | Up to 1200 m (total extended length) |
| Installation | ANB10*, ANB11*, ANR10*, AFF50*, AFV10*, AFV30*, or AFV40* |
| Max per FCU | 6 modules (3 pairs if dual-redundant) |
| Explosion Protection | Non-explosion-proof (S50) |
| Typical Application | Modbus-RTU communication, serial device integration, PLC interfacing, analyzer communication |
Suffix reference: S = standard type; 5 = non-explosion-proof; 0 = basic type.
Key Selling Points & Differentiators
- Dual RS-422/RS-485 ports: Supports both point-to-point and multipoint serial communication.
- Modbus-RTU capable: Commonly used as the DCS-side master for Modbus-RTU integration with third-party PLCs and instruments.
- Long transmission distance: Up to 1200 m total extended length for RS-422/RS-485 networks.
- Non-explosion-proof basic type: The S50 suffix confirms it is suitable for general industrial areas without explosion-proof requirements.
- Direct CENTUM CS 3000 fit: Designed for YOKOGAWA FCS racks, making it a practical OEM replacement for maintenance or spares.
- Not recommended for: RS-232 applications (use ALR111), Ethernet communication (use ALE111), Foundation fieldbus (use ALF111), explosion-proof areas, or remote node installation.
Quality Transparency SOP
Serial communication modules should be verified for both physical integrity and communication functionality.
- Incoming visual QA: Inspect factory sealing, label integrity, connector pins, PCB condition, and corrosion indicators.
- Label verification: Confirm full model and suffix match the required configuration.
- Connector inspection: Check RS-422/RS-485 port connectors for bent pins, oxidation, or mechanical damage.
- Communication check: Verify baud rate, parity, and protocol settings match the existing CENTUM CS 3000 project configuration.
- Final packing: Record serial/lot information, apply anti-static packaging, and seal with a condition label.
Technical Risk Avoidance
Confirm the interface type. ALR121 is RS-422/RS-485; ALR111 is RS-232. They are not interchangeable.
Verify the suffix code. ALR121-S50 is non-explosion-proof basic type. If the existing card is ALR121-SE0/SE1, the explosion-proof rating must be confirmed before substitution.
Do not install in remote nodes. ALR111 and ALR121 modules cannot be installed in remote node units (ANR10*).
Respect the per-FCU limit. A single FCU supports a maximum of 6 ALR111/ALR121 modules, or 3 pairs if dual-redundant.
Check wiring and polarity. RS-485 connections require correct A/B polarity and shielded twisted-pair cabling with single-end grounding to avoid communication faults.
Confirm project configuration. Baud rate, parity, stop bits, and protocol settings must match the existing CENTUM CS 3000 engineering configuration before installation.
Buyer’s FAQ
Is this module genuine YOKOGAWA?
Yes. The is an OEM YOKOGAWA CENTUM CS 3000 serial communication module. We supply it as new original/new surplus unless otherwise stated.
What does S50 mean?
S = standard type; 5 = non-explosion-proof; 0 = basic type.
Can I use it for Modbus-RTU communication?
Yes. The ALR121 is commonly used as the DCS-side master for Modbus-RTU integration with third-party PLCs and serial devices.
Can I replace an ALR111 with this module?
No. ALR111 is RS-232, while ALR121 is RS-422/RS-485. The interface types are different.
Can it be installed in a remote node?
No. ALR111 and ALR121 cannot be installed in remote node units (ANR10*).
What is the warranty and lead time?
Each module carries a standard 12-month functional warranty from shipment, excluding damage from incorrect installation, wiring errors, or project configuration mismatch. In-stock units typically ship within 1–3 business days after payment confirmation.
