ALR121-S50 Yokogawa CENTUM VP Datasheet & Technical Manual

Communication Module | Yokogawa ALR121-S50 RS-422/RS-485 Serial

Communication Module | Yokogawa ALR121-S50 RS-422/RS-485 Serial

Availability: 10 left in stock

Yokogawa ALR121-S50 Serial Communication Module Configured for RS-422/RS-485 serial interface execution in CENTUM VP control networks, the Yokogawa ALR121-S50 (ALR121...

SKU: ALR121 -S51

Manufacturer: Yokogawa
Product No.: ALR121 -S51
Product Type: Communication Modules
Product Origin: JAPAN
Payment:T/T, Western Union
Weight: 300g
Shipping port: Xiamen
Warranty: 12 months

Description Reviews

Yokogawa ALR121-S50 Serial Communication Module

Configured for RS-422/RS-485 serial interface execution in CENTUM VP control networks, the Yokogawa ALR121-S50 (ALR121 Serial Communication Module) provides direct physical/electrical execution.

Suffix Breakdown & Model Matrix

Code	Option / Specification	Description
ALR121	Base Model	Serial Communication Module (2-Port RS-422/RS-485)
-S	Type	Standard Type
5	Environmental Protection	Standard Environment (No Explosion Protection)
0	Configuration	Basic Module Type

Hardware Specifications

Parameter	Specification
Model	ALR121-S50
Brand	Yokogawa
Origin	Singapore
Weight	0.30 kg (Net, 0.66 lbs)
Dimensions	3.28 cm x 14.29 cm x 13.00 cm
Operating Temp	-20 to +60 deg C
Power Consumption	0.50 A @ 5 VDC
Interface Ports	2 Ports (RS-422 / RS-485)
Communication Mode	Half-duplex
Baud Rates	1200 / 2400 / 4800 / 9600 / 19200 / 38400 bps
Synchronization	Start-stop asynchronous method
Transmission Code	ASCII / Binary
Network Topology	Point-to-point (RS-422), Multipoint (RS-485)

Industrial Communication and Protocol Processing

The ALR121-S50 module establishes serial data exchanges between field-mounted instrumentation and central processing units across Yokogawa CENTUM architectures. The hardware routes ASCII or binary code blocks using half-duplex start-stop synchronization over dual RS-422 or RS-485 physical lines. Integrated serial controllers support standard 4-20 mA HART loop protocol pass-through and subsystem fieldbus links, maintaining signal integrity and channel-to-channel isolation to block common-mode voltage spikes from entering the main backplane bus.

Frequently Asked Questions

Q: How does the ALR121-S50 differ from the legacy ALR121-S00 model?

A: The ALR121-S50 serves as the direct functional replacement for the ALR121-S00, updated to comply with current manufacturing standards while retaining matching pin assignments and electrical performance.

Q: What line termination resistance is required for RS-485 multipoint wiring on this module?

A: Match line termination resistance (typically 120 ohms) across both physical endpoints of the RS-485 bus to mitigate signal reflection along long cable paths.

Field Installation Guidelines

Align the ALR121-S50 module vertically with the designated I/O node slot on the rack backplane, sliding it inward until the card-edge connectors seat completely. Tighten the top and bottom captive screws to lock the physical assembly and verify structural ground contact. Terminate signal conductors using shielded twisted-pair cables, bonding cable drain shields to a dedicated terminal ground bar inside the cabinet to limit electromagnetic interference and electrical noise on serial lines.

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