Yokogawa ALR121-S00 S1 Serial Communication Module

Hardware Specifications

Process Communication and DCS Interface Characteristics

The Yokogawa ALR121-S00 S1 provides RS-422/RS-485 serial interfaces for connecting subsystem equipment to the CENTUM VP/CS 3000 Field Control Station. Moreover, the module supports half-duplex transmission with start-stop synchronization, allowing controlled data exchange between the FCS and external devices.

The module uses binary transmission coding with configurable communication speeds from 1200 bps to 38400 bps. In addition, the RS-485 multipoint connection capability allows multiple field devices to communicate through a shared serial network structure.

For Yokogawa process control applications, the module supports structured subsystem integration similar to other DCS communication interfaces. Therefore, engineers can apply this module for serial communication links with PLC systems, intelligent instruments, and external automation equipment.

Frequently Asked Questions (FAQ)

Q: What serial interfaces does the Yokogawa ALR121-S00 S1 support?
A: The module supports RS-422 and RS-485 interfaces. RS-422 provides point-to-point communication, while RS-485 supports multipoint network connections.

Q: What communication mode does the ALR121-S00 S1 use?
A: The module operates with half-duplex communication and uses start-stop synchronization with binary transmission coding.

Q: Can the module connect directly to multiple field devices?
A: Yes. The RS-485 interface supports multipoint communication configurations when the connected field devices follow the required serial communication wiring and protocol settings.

Field Installation Guidelines

• Install the ALR121-S00 S1 module in the designated Yokogawa FCS or compatible node unit slot according to the system hardware manual.
• Verify RS-422 or RS-485 wiring polarity before connecting field communication cables.
• Use shielded communication cables for serial signal wiring and connect cable shields according to the site grounding practice.
• Separate serial communication cables from high-voltage power lines and strong electromagnetic interference sources.
• Confirm transmission speed, character length, stop bit settings, and communication parameters before commissioning.
• Check connector seating and module mounting position before system startup.