A413125 Metso AIU-8 Analog Input Module

Description

Product Model: A413125
Product Brand: Metso (Valmet / Neles Automation)
Product Series / Type: AIU-8 Analog Input Module

Key Features:

• 8 analog input channels (AIU-8) as per vendor listings
• Compatible with Metso / Valmet automation / DCS control systems
• 24 VDC powered, typical input current ~30 mA (as vendor spec)
• Discontinued by manufacturer but commonly available in surplus / repair market

Role & System Integration

The Metso A413125 is an AIU-8 analog input module, often used in Metso / Valmet DCS (Distributed Control System) / PLC environments to capture analog signals from field instrumentation (flows, pressures, temperatures, etc.). The “AIU-8” designation signals that it supports 8 analog input channels.

This module sits inside a control rack or terminal backplane, where field analog loops are wired in, and the module converts those signals into digital data for the DCS / control logic to read. Because it is part of the Metso / Valmet control ecosystem, its signal ranges, termination styles, and communication protocols are tailored to that environment.

Given that many vendor listings describe the module as “discontinued” or “surplus / OEM replacement,” it often serves in maintenance, repair, or legacy system support roles.

The module may come in multiple revision versions (Rev 04, Rev 08, etc.) as seen in some listings.

Technical Features & Benefits

Below is a breakdown of confirmed and inferred technical features, along with observations relevant for application.

Channel Count & Function

• Supports 8 analog input channels (AIU-8) per module listing.
• Signals are likely standard industrial analog ranges (0–10 V, 4–20 mA, etc.), depending on system wiring and the module’s configuration. The exact supported ranges are not published in the sources I found.
• The module is described in some vendor specs as operating at 24 V DC supply and drawing about 30 mA (i.e. modest module current).

Physical / Electrical Details

• According to Radwell’s listing, A413125 is a “circuit board input module” with 8 analog inputs, in a 24 VDC environment, drawing ~30 mA.
• Weight is listed as approximately 0.26 lbs (~0.12 kg) in vendor spec pages.
• The module is classified as “industrial computer accessory / PLC peripheral module.”
• It is noted as discontinued in vendor catalog pages.

Because internal component details (resolution, input isolation, filtering, tolerances) are not broadly published, those specifics must be confirmed via the original module or service documentation.

Technical Specifications Table

Installation & Maintenance Insights

Here are practical tips and caveats when deploying or maintaining A413125 modules.

Installation & Rack Handling

• Power down the control system or rack before inserting or removing the module to protect against bus faults or damage.
• Ensure proper seating on the backplane / rack connector — misalignment or poor contact can cause erratic channel readings.
• Because the module is often used in legacy systems, cleanliness, connector integrity, and mechanical support are important to avoid intermittent faults.

Wiring & Calibration

• Use shielded twisted-pair cables for analog input signals to minimize noise and interference, especially over long cable runs.
• Maintain consistent grounding practices — the analog module is sensitive to ground loops, so shield termination and grounding must be planned.
• During commissioning, apply known analog test signals (e.g. 4 mA, 12 mA, 20 mA, or corresponding voltage ranges) and verify reading linearity.
• If multiple revisions exist (Rev 04, Rev 08, etc.), confirm that any firmware or calibration tables correspond to the module revision to avoid mismatches.

Spares & Obsolescence Strategy

• Because the module is discontinued, maintain at least one spare module if long-term system support is required.
• Prefer spares that match revision (e.g. Rev 08 vs Rev 04) to reduce compatibility surprises.
• Before deploying a spare, test all input channels offline to ensure calibration and correct response.
• Document wiring and channel mapping thoroughly to facilitate replacement without error.

Fault Handling & Diagnostics

• Monitor analog channel readings for drift, noise, stuck / saturated values, which may indicate wiring faults or aging components.
• If a channel fails, check field wiring first (loose connections, broken wires) before replacing the module.
• If module failure is suspected, remove and bench test individually to confirm the fault.

Related / Complementary Modules

• AIU-8 family equivalents — other Metso / Valmet analog input modules (e.g. AIU-16, or sibling versions)
• Analog Output / I/O boards — modules in the same control rack that provide analog outputs or mixed I/O
• DCS / PLC Interface modules — modules that communicate the AI data to control logic, alarm systems, historian storage

Because modules in the same rack share power, bus, and backplane constraints, you should consider total current and thermal loading when mixing several modules.