Overview
Manuals
Main Features
Core Applications and Functions
Features:
- Serial Communication Modules
- Dual-redundant Communication
- ALR121 Serial Communication Modules used with a safety control station (SCS) for performing Modbus communication
The dual-redundant configuration can be provided by setting the serial communication modules on an adjacent slot. Each of the ALR111 and ALR121 modules has two ports; however, the dual-redundant communication requires two communication modules.
The two sets of dual-redundant communication are enabled by two ports of ALR111/ALR121; however, the communication control is defined by each communication module. When one of the communication ports detects an error, both ports switch over the control/stand-by sides to the redundant module.
The ALR121-S51 S1 YOKOGAWA Serial Communication Modules may still be available for purchase and support from Moore Automated Company beyond End-Of-Life (EOL) by the manufacturer (OEM).
YOKOGAWA ALR121-S51 S1 Serial Communication Modules DATASHEET(manual), Link
Important Notice: Other accessories, manuals, cables, calibration data, software, etc. are not included with this equipment unless listed in the above stock item description. All prices are shown in USD.
ALR121 acquires ProSafe-SLS events and data by the ProSafe-SLS communication function, which enables SCS to use those events and data in the same way as general analog and digital I/O signals. ProSafe-SLS’s system time has to be synchronized with ProSafe-RS by digital input and output modules to match the event time stamp. A bleeder resistor has to be connected on the ProSafe-SLS side to match the I/O specification of ProSafe-SLS and ProSafe-RS.
- Subsystem Integration: Acts as a bridge between the Field Control Station (FCS) or Safety Control Station (SCS) and external devices such as PLCs (e.g., Modbus, FA-M3, MELSEC-A, SLC500), burner management systems, and emergency shutdown systems.
- Communication Protocols: Primarily uses Modbus (as master or slave), but also supports proprietary protocols for communication with FA-M3, YS, and other controllers.
- Safety-Critical Automation: Commonly used in high-integrity industries such as oil and gas, chemical, and power generation, and can be part of a SIL3 certified safety strategy.
- Redundancy Support: Two modules can be configured as a dual-redundant pair, ensuring uninterrupted data exchange even if one module or communication path fails.
