Description
Modicon AS-J890-002 | S908 Remote I/O Interface | Dual-Cable 800 Series Adapter
Key Technical Specifications
| Parameter | Specification |
|---|---|
| Model | AS-J890-002 |
| Manufacturer | Modicon / Schneider Electric |
| Product family | 890 / 800 Series |
| Function | Remote I/O interface / drop adapter |
| RIO protocol | S908 |
| Compatible I/O | 800 Series |
| RIO cable ports | 2 |
| ASCII ports | 0 |
| Head-end compatibility | S908 or CRP93X RIO processor |
| Internal termination | No |
| Required termination | External in-line terminator |
| Typical network role | Remote I/O drop interface |
Schneider’s S908 communication documentation lists AS-J890-002/102 as an 800 Series drop adapter supporting two RIO cable connections and no ASCII ports. The same documentation identifies S908 or CRP93X as compatible head-end processor families.
A particularly important installation detail is termination. The older J890/J892 adapters, including AS-J890-002, do not provide internal RIO termination and require an in-line terminator in the drop cable. Schneider’s documentation specifically warns that disconnecting an unterminated cable while the network is running can introduce communication errors and transfer delays.
Product Introduction
The Modicon AS-J890-002 is a dual-cable Remote I/O interface used to connect 800 Series I/O at a remote drop to an S908 Remote I/O network. It belongs to the older Modicon 890/800 Series architecture and is commonly described in legacy documentation as an RIO processor or 984/800 RIO interface.
Its two RIO cable ports are the important distinction from the single-port AS-J890-001. For an existing plant, replacement should be based on the installed RIO architecture rather than simply matching the physical connector arrangement. The external termination requirement is also significant during commissioning and troubleshooting.
AS-J890-002
Application Scenarios & Field Pitfalls — Engineer’s Perspective
Engineering Pain Point
The main problem with AS-J890-002 replacement is usually not the I/O count. It is preserving the behavior of an established remote I/O network, including the two-cable topology, drop addressing, termination arrangement, and compatibility between the head-end processor and 800 Series I/O.
Typical Applications
- Modicon 984 remote I/O systems — interfaces 800 Series I/O at a remote drop.
- RIO networks — provides the dual-cable connection between the remote drop and RIO network.
- Legacy plant PLC systems — useful where migration away from 800 Series hardware has not yet occurred.
- Redundant/dual-cable RIO installations — appropriate where two RIO cable connections are required at the drop.
Technical Pitfalls to Avoid
- Do not substitute AS–001 simply because it looks similar.
AS–001 has one RIO cable port, w AS- provides two. The documentation explicitly distinguishes these variants. - Do not omit the external RIO terminator.
AS- is one of the older adapters without internal termination. Schneider documentation identifies an in-line terminator as necessary for these installations. - Do not confuse with J892.
AS-J892-002 is also a dual-port 800 Series adapter, but the J892 family supports ASCII devi AS- has no ASCII ports. - Check the actual head-end processor.
The documented architecture identifies or CRP93X processors as the applicable head-end families. A physical connector match does not establish network compatibility.
Related Products
- AS–001 — Single-RIO-port version for 800 Series I/O; suited to installations requiring one RIO cable rather than two.
- AS–101 — Later variant associated with the single-port 800 Series architecture.
- AS–102 — Later variant associated with the dual-port 800 Series architecture.
- AS-J892-002 — Dual-RIO-port 800 Series adapter with ASCII support; not a direct functional substitute where ASCII requirements differ.
- AS-J892-001 — Single-RIO-port counterpart in the ASCII-capable family.
- AS-P890-000 — RIO adapter for 800 Series I/O with one RIO port.
- AS-P892-000 — RIO adapter for 800 Series I/O with ASCII capability.
- 60-0513-000 — In-line RIO cable terminator associated with older / adapters.
Procurement Note
For a replace AS-, verify the complete part number, hardware revision, two-port configuration, network architecture, external termination arrangement, and installed 800 Series I/O before approving a substitute.
The model is legacy hardware, so a visually similar / or newer adapter should not be treated as a drop-in replacement without checking the control-system drawings and network configuration. Older documentation also uses the descriptions “RMT PROCESSOR” and “984/800 RIO IFC,” which can cause catalog searches to return inconsistent product classifications.
