Description

Yokogawa ALR121-S53 Serial Communication Module

Configured for serial data communication in Yokogawa Field Control Station architectures, the Yokogawa ALR121-S53 (ALR121 Serial Communication Module) provides direct physical/electrical execution of RS-422 and RS-485 communication functions between control stations and connected subsystems. The module supports dual communication ports, start-stop synchronization, ASCII or binary transmission formats, and half-duplex operation for subsystem integration.

Suffix Breakdown & Model Matrix

Model Element	Description
ALR121	Serial Communication Module
-S	Standard type
5	Basic type without explosion protection
3	ISA Standard G3 corrosion-resistant specification

Hardware Specifications

Parameter	Specification
Model	ALR121-S53
Brand	Yokogawa
Origin	Japan
Product Type	Serial Communication Module
Interface	RS-422 / RS-485
Number of Ports	2
Communication Method	Half-duplex
Synchronization Method	Start-stop synchronization
Transmission Code	ASCII / Binary
Character Length	7 bits / 8 bits
Stop Bit Length	1 bit / 2 bits
Parity Check	None / Even / Odd
Transmission Speed	1200 / 2400 / 4800 / 9600 / 19200 / 38400 bps
Maximum Transmission Distance	Up to 1200 m
RS-485 Topology	Multipoint communication
RS-422 Topology	Point-to-point communication
Current Consumption	0.5 A
Weight	Approx. 0.34 kg
Mounting Compatibility	AFV30, AFV40, ANB10, ANB11 and compatible field control units
Wiring Method	Terminal block with M4 screw connections

Channel Isolation and DCS Communication Integration

As a Yokogawa DCS communication module, the ALR121-S53 is intended for subsystem-level serial data exchange through RS-422 or RS-485 physical layers. Communication parameters including baud rate, parity, character length, and stop bits can be configured to match connected subsystem requirements.

The module supports ASCII and binary transmission modes and can be integrated with Modbus RTU slave communication functions where system configuration permits. Dual communication ports allow independent connections to external controllers, intelligent devices, or subsystem interfaces within the same control platform.

Frequently Asked Questions

Q: Does the ALR121-S53 support both RS-422 and RS-485 networks?
A: Yes. The module supports RS-422 point-to-point communication and RS-485 multipoint communication through its serial communication interfaces.

Q: What is the maximum supported communication distance?
A: The specified total extended transmission distance is up to 1200 m when suitable communication cable and installation practices are applied.

Q: Can communication parameters be configured for different field devices?
A: Yes. The module supports selectable baud rates, parity settings, character lengths, stop bits, and transmission formats according to system configuration requirements.

Field Installation Guidelines

• Verify that RS-422 or RS-485 network topology matches the connected subsystem design before commissioning.
• Use shielded communication cable recommended by the system documentation, such as approved multi-pair shielded industrial communication cable.
• Route communication wiring separately from high-voltage power cables to reduce electromagnetic interference.
• Ground cable shields according to plant grounding standards and DCS installation requirements.
• Confirm baud rate, parity, character length, and stop-bit settings are identical at both communication endpoints before energizing the network.
• Tighten terminal block connections according to approved maintenance procedures and inspect periodically for loosened conductors.
• Observe controller cabinet environmental requirements specified by the host control system documentation.

Specifications

• Brand: Yokogawa

Advantages

• High reliability in industrial environments
• Supports continuous operation
• Compatible with major PLC/DCS systems