Yokogawa ALR121-S01 RS-422 / RS-485 Serial Communication Module
A serial communication module for point-to-point RS-422 or multipoint RS-485 links in approved CENTUM VP node units.
Key Information
ALR121-S01 is the Yokogawa serial communication module used to exchange data with compatible third-party equipment through RS-422 or RS-485. It supports one point-to-point RS-422 path or an RS-485 multipoint network.
The module uses asynchronous start-stop communication and supports ASCII or binary data. The selected character length, stop bits and parity must agree with every device on the link.
Selection is tied to the installed node unit, cable type and network topology. Yokogawa lists installation in approved AFV and ANB field-control or node units rather than stand-alone use.
Functions
Serial device integration
Links compatible analyzers, controllers and other serial devices to a CENTUM VP field-control environment.
Protocol framing
Supports configurable 7-bit or 8-bit characters, one or two stop bits, and none, even or odd parity.
Network reach
Supports a documented total cable length up to 1,200 m when the approved electrical and installation conditions are met.
Dual-module planning
Allows two modules to be installed as a redundant pair when the system architecture and engineering application support it.
Specifications
| Manufacturer | Yokogawa | Exact model | ALR121-S01 |
|---|---|---|---|
| Product designation | Serial Communication Module | Communication standard | RS-422 or RS-485 |
| Topology | Point-to-point RS-422; multipoint RS-485 | Duplex mode | Half-duplex |
| Synchronization | Start-stop | Transmission rates | 1,200 / 2,400 / 4,800 / 9,600 / 19,200 / 38,400 bit/s |
| Data format | ASCII or binary | Character length | 7 or 8 bits |
| Stop bits | 1 or 2 | Parity | None, even or odd |
| Maximum total cable length | 1,200 m | Supported mounting | Approved AFV10, AFV30, AFV40, ANB10 and ANB11 units |
| Ambient range | 0 to 60 °C for S01 execution |
About IndustryParts
https://www.industryparts.com/Serial settings remain attached to the installed link
IndustryParts keeps the exact module identity, node-unit position, physical-layer choice and peer-device settings together for review.
- Exact submitted model retained
- Installed-system evidence reviewed
- Quotation identity kept traceable
Installation
Record the complete link
Capture the peer device, port standard, cable, shielding, termination, address and serial framing before any exchange.
Match the physical layer
Use RS-422 only for the documented point-to-point path and RS-485 for the approved multipoint arrangement.
Commission from both ends
Verify message framing, error handling and stable exchange at the selected bit rate before returning the link to service.
Lifecycle
Configuration custody
Keep the serial parameters and peer-device manual with the CENTUM project record.
Cable and termination review
Inspect screen bonding, routing, connector condition and RS-485 end termination during planned service.
Spare control
Retain the complete S01 identity and node-unit position so a nearby ALR execution is not accepted by family name alone.
Related Models
FAQ
What communication record should accompany a ALR121-S01 enquiry?
Provide the node-unit model, slot, peer-device manuals, RS-422 or RS-485 topology, cable route, framing and bit rate.
Can ALR121-S01 be selected from connector appearance alone?
No. The electrical standard, point-to-point or multipoint topology, approved node unit and complete S01 identity must all match.
What limits an RS-485 expansion using ALR121-S01?
The approved device count, cable length, termination, grounding and every participant’s RS-485 capability must be checked as one network.
Can ALR121-S01 exchange data before the peer protocol is defined?
No. The physical link is only one layer; message format, timing and error handling must also be engineered for the connected device.
What proves ALR121-S01 is ready after replacement?
Stable bidirectional exchange, correct framing, clean diagnostics and a retained as-left port record complete the service evidence.
Send the complete ALR121-S01 identity
Include requested quantity, destination and the installed-system evidence needed for compatibility review.
