Description
The Yokogawa ALR111-S51 is a dedicated serial communication module designed for dependable integration within Yokogawa Safety Control Station systems. It provides stable RS-232C communication and ensures external devices can exchange data efficiently with SCS platforms. Moreover, its support for Modbus slave communication allows supervisory controllers, PLCs, and DCS systems to access SCS data without complexity. The module maintains robust performance in harsh industrial environments, and its compact design simplifies installation on both safety control units and safety node units. In addition, its predictable timing behavior offers reliable data exchange where safety and consistency matter.
Key Features
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Supports two independent RS-232C communication ports for flexible system integration
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Enables Modbus slave and subsystem communication for smooth data access
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Designed for secure interaction between SCS and external subsystems
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Offers selectable communication speeds and codes for diverse serial architectures
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Provides stable operation within demanding industrial automation environments
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Allows easy mounting on safety control or safety node units
Technical Specifications
Product Type:
Model: ALR111-S51
Communication Standard: RS-232C
Ports: 2 communication ports
Transmission Speed: 1200/2400/4800/9600/19200/38400 bps
Data Rate Range: 1200 bps to 115.2 kbps
Transmission Code: ASCII or Binary
Character Length: 7 or 8 bits
Stop Bit Length: 1 or 2 bits
Parity Check: None / Even / Odd
Communication Function: Half-duplex
Synchronization: Start-stop synchronization
Lag Time After Transmission: 1 ms
Maximum Transmission Distance: 15 m
Supported Protocols: Modbus slave communication, subsystem communication
Mounting Options: Safety control unit or safety node unit
Current Consumption: 0.5 A
Weight: 0.3 kg
Typical Applications
The ALR111-S51 is frequently used in safety-critical process units where reliable serial communication links external PLCs, subsystem controllers, or monitoring equipment with the SCS. For instance, many facilities deploy the module to exchange command and diagnostic data across legacy serial networks while maintaining predictable communication timing. Moreover, its Modbus slave capability ensures compatibility with a wide range of supervisory automation platforms.
Support & Reliability
Yokogawa designs the ALR series with long-term system availability in mind, and the ALR111-S51 follows the same principles. Therefore, its consistent communication behavior supports preventive maintenance planning and reduces troubleshooting time. In addition, stable hardware construction ensures dependable operation over extended service cycles.
FAQ
Q1: Does the ALR111-S51 support Modbus master communication?
No, it supports Modbus slave communication and responds to requests from a Modbus master device.
Q2: Can the module be installed on non-safety FCU units?
It is designed for safety control units and safety node units in Yokogawa SCS systems.
Q3: What is the maximum cable length for RS-232C communication?
The supported transmission distance is up to 15 meters.
Q4: Does the module support full-duplex communication?
No, it operates in half-duplex mode with start-stop synchronization.
Q5: What external systems commonly connect to the ALR111-S51?
Typical systems include PLCs, DCS equipment, monitoring terminals, and subsystem controllers using RS-232C links.
