ALR121-S00 S1 YOKOGAWA Communication Module

YOKOGAWA ALR121-S00 S1 Serial Modbus Communication Module

YOKOGAWA ALR121-S00 S1 Serial Modbus Communication Module

Availability: 20 left in stock

YOKOGAWA ALR121-S00 S1 Serial Communication Module Configured for serial data exchange in CENTUM VP, CS 3000, and Safety Control Station...

SKU: ALR121

Manufacturer: Yokogawa
Product No.: ALR121
Product Type: Communication Modules
Product Origin: JAPAN
Payment:T/T, Western Union
Weight: 1500g
Shipping port: Xiamen
Warranty: 12 months

Description Reviews

YOKOGAWA ALR121-S00 S1 Serial Communication Module

Configured for serial data exchange in CENTUM VP, CS 3000, and Safety Control Station (SCS) platforms, the YOKOGAWA ALR121-S00 S1 (ALR121-S00 Serial Communication Module) provides direct physical/electrical execution. The hardware provides RS-422 and RS-485 interfaces to execute Modbus communication protocols, bridging internal controller data directly to external supervisory master systems.

Hardware Specifications

Parameter	Specification
Model	ALR121-S00 S1
Brand	YOKOGAWA
Origin	USA
Weight	1.5 kg
Dimensions	2.2 cm x 12.4 cm x 12.6 cm
Operating Temp	0 to 55 deg C
Power Consumption	24 VDC nominal backplane supply
Interface Ports	RS-422 / RS-485 serial interfaces (4-wire system)
Bus Protocol	Modbus RTU / ASCII communication protocol
Connection Topology	Point-to-point (RS-422), Multipoint (RS-485)
Isolation Rating	Galvanic isolation between serial channels and system backplane bus

Serial Protocol Execution and Channel Isolation

The module manages serial transmission across dedicated RS-422 point-to-point links and RS-485 multi-drop networks, utilizing standard 4-wire hardware connections. Integrated galvanic isolation shields internal backplane processing logic from voltage spikes, ground loops, and electrical noise present along external serial field wiring. The onboard controller manages Modbus register access to read and write variables inside host control stations, maintaining channel diagnostic LED states to indicate active data transmission, port configuration faults, and frame errors in real time.

Frequently Asked Questions

Q: How does the serial interface handle channel-to-system electrical noise isolation?

A: Integrated galvanic isolation barriers completely decouple the RS-422/RS-485 transceiver circuitry from the internal controller backplane, preventing field loop voltage transients from affecting CPU bus operation.

Q: What topology configuration options exist for the serial ports?

A: The hardware supports 4-wire RS-422 point-to-point configurations for dedicated single-device links, as well as 4-wire RS-485 multipoint bus networks connecting multiple Modbus slaves.

Q: Does the module support Modbus data modification from external systems without stopping controller execution?

A: Yes, external Modbus master devices read and modify designated data registers within the controller system asynchronously over the serial link while host control logic runs continuously.

Field Installation Guidelines

Disconnect backplane rack power before seating or removing the communication module from the system chassis slot.
Use shielded twisted-pair cabling designed specifically for RS-422/RS-485 industrial communication networks to minimize signal attenuation.
Connect cable shield drain wires directly to the system cabinet earth ground bar, ensuring the field terminal end remains isolated to prevent ground loops.
Install termination resistors across the receiver terminals at the physical ends of the RS-485 multipoint network to suppress line reflections.
Maintain clear airflow around chassis card slots so operating temperatures remain strictly within the 0 to 55 deg C environmental limits.

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