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ALR121-S51 S1

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Yokogawa ALR121-S51 S1 is a two-port RS-422/RS-485 serial communication module with ISA Standard G3 environmental protection.
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Technical specifications for ALR121-S51 S1

  • Manufacturer:
    Yokogawa
  • Part Number:
    ALR121-S51 S1
  • Product Family:
    Centum CS-Centum VP
  • Product Type:
    Serial Communication Module
  • Stock:
    1
  • Interface:
    RS-422 / RS-485
  • Number of Ports:
    2
  • Connection Method:
    Point-to-point (RS-422), Multipoint (RS-485)
  • Synchronization:
    Start-stop synchronization
  • Transmission Distance:
    Max. 1200 m (total extended length)
  • Current Consumption:
    0.5 A
  • Weight:
    0.661 lbs (0.3 kg)
  • Estimated shipping dimensions:
    32.8 x 142.9 x 130 mm
  • Tariff Code:
    Please confirm the destination before shipping.
  • Country of origin:
    Japan
  • Place of shipment:
    Xiamen, Fujian, China
By purchasing this item, you agree to the Terms & Conditions, ApterPower is not an authorized distributor for listed manufacturers or tradenames and therefore the manufacturer's warranty does not apply. All our products come with ApterPower's 1-year warranty.

More Information

Overview Manuals Specifications Protocol Support G3 Environment Redundant Links

Features:

  • G3 construction: S51 includes the ISA Standard G3 environmental option
  • Two serial ports: RS-422 point-to-point and RS-485 multipoint communication
  • Configurable transfer: selectable speed, data format, parity, and stop bits
The ALR121-S51 S1 is the standard, non-explosion-protected ALR121 configuration with the G3 environmental option.

It exchanges subsystem data through two half-duplex serial ports and supports the communication functions documented by Yokogawa.

Select the correct protocol, cable, termination, and supported host unit for the planned subsystem connection.

Availability is subject to Apter Power inventory and sourcing confirmation.
Yokogawa ALR121-S51 S1 G3 Serial Communication Module Specifications

General

  • ManufacturerYokogawa
  • ModelALR121-S51 S1
  • ConditionNew and factory sealed
  • Product FamilyN-IO/FIO Serial Communication Modules
  • FA-M3 links: supports documented FA-M3 serial communication functions
  • Open protocols: supports documented Modbus serial communication
  • Subsystem families: includes documented MELSEC-A, YS, SLC500, and PLC-5 functions
  • Port rule: both module ports use the same selected communication function
  • Standard type: suffix S identifies the standard ALR121 construction
  • No explosion protection: suffix 5 identifies the non-explosion-protected version
  • G3 option: suffix 1 adds ISA Standard G3 environmental protection
  • Selection check: do not substitute S50 or S53 without confirming the required environment
  • Adjacent slots: use an identical pair in neighboring even and odd positions
  • Standby data: the standby module retains synchronized output image data
  • Fault transfer: the FCS changes control after a module or subsystem communication failure
  • Write limitation: dual-redundant operation does not support the one-shot write specification
Description
The Yokogawa ALR121-S51 S1 is a two-port RS-422/RS-485 serial communication module for N-IO and FIO field control stations.

It supports half-duplex communication, start-stop synchronization, ASCII or binary data, and transmission speeds from 1200 to 38400 bps.

The S51 configuration is the standard type without explosion protection and includes the ISA Standard G3 option.
Alternative Names
ALR121-S51 ALR121 S51 S1 Yokogawa ALR121-S51 ALR121 G3 Serial Communication Module
Technical notes
ALR121-S51 S1 combines two RS-422/RS-485 ports with ISA Standard G3 protection. Confirm protocol, baud rate, cable, and host-unit compatibility before commissioning.
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FAQS

The following is a list of questions commonly asked by our customers. Please contact us if you have a question about our process that is not answered below.
What distinguishes ALR121-S51 S1 from the S50 configuration?
The S51 suffix includes the ISA Standard G3 environmental option; S50 is the basic type.
Which interfaces are available on ALR121-S51 S1?
It provides two RS-422/RS-485 serial communication ports.
What is the maximum RS-485 transmission distance?
Yokogawa specifies a maximum total extended length of 1200 m.
Can ALR121-S51 S1 be configured for dual-redundant communication?
Yes. Install two identical modules in adjacent slots and follow Yokogawa redundancy requirements.
Which serial communication functions are documented for ALR121?
Documented functions include FA-M3, Modbus, MELSEC-A, YS, SLC500, and PLC-5 communication.
Which host units accept ALR121-S51 S1?
It mounts on supported ANB, AFV, and A2FV node or field control units listed by Yokogawa.