ALR121-S53 Yokogawa ALR121 Serial Communication Modules

Hardware Specifications

Serial Communication and Interface Characteristics

The Yokogawa ALR121-S53 provides two serial communication ports for exchanging data between the control system and connected subsystem equipment.

Its RS-422/RS-485 interface uses a 4-wire communication configuration. This arrangement separates transmission and reception signal paths, allowing the module to support serial data exchange with compatible equipment.

The module supports two communication functions:

• Modbus Slave Communication: Allows compatible Modbus master equipment to access data through the module.
• Subsystem Communication: Supports serial communication with connected subsystem equipment.

For field wiring, maintain the specified RS-422/RS-485 signal assignments and separate communication cables from high-voltage power conductors where practical. Use appropriate cable shielding and grounding practices to reduce electromagnetic interference.

Frequently Asked Questions (FAQ)

Q: How many communication ports does the Yokogawa ALR121-S53 provide?

A: The ALR121-S53 provides two RS-422/RS-485 communication ports.

Q: Which communication protocols or functions does the ALR121-S53 support?

A: The module supports Modbus slave communication and subsystem communication.

Q: What is the current consumption of the ALR121-S53?

A: The specified current consumption is 0.5 A. Confirm the applicable system power budget before installation.

Field Installation Guidelines

1. Verify the module identification: Confirm the complete ALR121-S53 model designation before installation.
2. Check mounting compatibility: Install the module in its designated Yokogawa system position according to the applicable hardware documentation.
3. Inspect communication wiring: Verify RS-422/RS-485 signal assignments and maintain the required 4-wire configuration.
4. Manage cable routing: Separate serial communication wiring from high-voltage conductors and other significant interference sources.
5. Apply shielding practices: Terminate cable shields according to the system grounding design and avoid unintended ground loops.
6. Verify power loading: Account for the specified 0.5 A current consumption when checking the system power supply capacity.
7. Confirm communication settings: Match the connected equipment’s communication configuration with the applicable system requirements before commissioning.