ALSTOM AB121 Digital I/O Interface Module

Technical Specifications

Model：AB121

Brand：ALSTOM

Product Type：Digital I/O interface module

Applicable System：ALSTOM Alspa series DCS rack

Supply Voltage：24V DC (backplane power supply)

Channel Configuration：8‑channel relay output,SPDT contact

Contact Rating：5A @250VAC ,5A @30VDC

Isolation Voltage：2000V AC galvanic isolation between field side and logic side

Communication Interface：Backplane internal system bus

Status Indicator：Multi‑color LED for power,channel status and fault diagnosis

Built‑in Function：Signal galvanic isolation,alarm & trip output,interlock logic signal processing

Working Temperature：‑10℃ ~ +55℃

Storage Temperature：‑20℃ ~ +70℃

Protection Class：IP20

Mounting：Plug‑in slot installation inside control rack

Weight：0.45kg

Product Brief:

AB121 is legacy plug‑in digital I/O module for ALSTOM Alspa DCS rack system. It provides multi‑channel isolated relay dry‑contact outputs for trip command,alarm signal and interlock logic transmission between control system and field equipment. High galvanic isolation protects internal logic circuit from field surge interference. Module transmits data and receives power through rack backplane bus. Front‑panel LED indicators support quick on‑site fault checking without extra testing tools. This is EOL discontinued spare part,widely used for power plant turbine control,substation automation renovation and maintenance. Please confirm hardware revision,channel configuration and rack compatibility before purchase. Strict ESD anti‑static protection must be followed during installation.