Features:
- G3 construction: S51 includes the ISA Standard G3 environmental option
- Two serial ports: RS-422 point-to-point and RS-485 multipoint communication
- Configurable transfer: selectable speed, data format, parity, and stop bits
The ALR121-S51 S1 is the standard, non-explosion-protected ALR121 configuration with the G3 environmental option.
It exchanges subsystem data through two half-duplex serial ports and supports the communication functions documented by Yokogawa.
Select the correct protocol, cable, termination, and supported host unit for the planned subsystem connection.
Availability is subject to Apter Power inventory and sourcing confirmation.
Verified resources for Yokogawa ALR121-S51 S1:
Yokogawa ALR121-S51 S1 G3 Serial Communication Module Specifications
General
- ManufacturerYokogawa
- ModelALR121-S51 S1
- ConditionNew and factory sealed
- Product FamilyN-IO/FIO Serial Communication Modules
- FA-M3 links: supports documented FA-M3 serial communication functions
- Open protocols: supports documented Modbus serial communication
- Subsystem families: includes documented MELSEC-A, YS, SLC500, and PLC-5 functions
- Port rule: both module ports use the same selected communication function
- Standard type: suffix S identifies the standard ALR121 construction
- No explosion protection: suffix 5 identifies the non-explosion-protected version
- G3 option: suffix 1 adds ISA Standard G3 environmental protection
- Selection check: do not substitute S50 or S53 without confirming the required environment
- Adjacent slots: use an identical pair in neighboring even and odd positions
- Standby data: the standby module retains synchronized output image data
- Fault transfer: the FCS changes control after a module or subsystem communication failure
- Write limitation: dual-redundant operation does not support the one-shot write specification