Product Details:

MODICON AS-B814-108, also known as B814-108, belongs to the Modicon 800 series discrete I/O family and is compatible with Modicon 984 rack PLC systems. It is an eight-channel fused relay output module, each output channel fitted with an independent fast acting glass fuse for individual circuit protection against overload and short circuit on field loads. The relay contacts support mixed AC and DC load driving, suitable for actuators, contactors, indicator lamps, solenoid valves and other general field devices that require isolated switching control. This module plugs directly into the dedicated 800 series backplane and exchanges logic data with the host CPU via the parallel backplane bus. Each channel has corresponding LED indicator to show relay status, helping maintenance staff quickly locate abnormal channels during on-site inspection. Built-in EMC filtering and surge suppression circuits enhance anti-interference ability, making it stable for continuous operation beside inverters and heavy contactors on production lines. It adopts natural convection cooling without fan, improving long-term reliability. As an obsolete original industrial spare part, it is widely used for maintenance and retrofit of aging Modicon 984 automation racks. Direct drop-in replacement keeps the existing field wiring, I/O address mapping and PLC control program unchanged, reduces rework and cuts production downtime.

Basic Parameters

Product type: fused relay discrete output module

Part number: AS-B814-108, B814-108

Series: Modicon 800 I/O series

Channel count: 8 independent relay output points

Fuse: individual 3AG fast acting fuse per channel

Compatible controller: Modicon 984 PLC rack

Mounting: single slot plug-in for 800 series backplane

Cooling: natural convection

Operating temperature: 0°C ~ +60°C

Protection grade: IP20

Supported Functions

Isolated relay switching for field actuators and loads

Independent channel fuse protection against short circuit

Backplane data communication with host 984 CPU

Per-channel status LED indication

Module self-diagnosis and fault detection

Internal noise filtering and transient surge suppression

Core Functions

Conversion of internal PLC logic signal into dry contact switching output

Onboard LED channel status indication for fast troubleshooting

Separate fuse protection to limit fault spread among channels

Surge withstand capability complying with industrial surge standards

Modular expansion for discrete control points on legacy Modicon racks

Stable long-running switching for general industrial loads

Hardware Specifications & Environmental Features

Built-in EMI filter and per-channel fuse protection circuit

Storage temperature: -25°C ~ +70°C

Relative humidity: 5% to 95% non-condensing

Status: Obsolete original part, available for spare replacement

Industry Applications:Applied in legacy petrochemical distributed control, old paper making production automation, water treatment remote signal collection and large conveyor remote I/O control racks.

Note:Confirm 800 series backplane compatibility, I/O address assignment and fuse specification before ordering.

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