VME-2528 Opto Isolated Digital Input Board

Module Feature

VME-2528 is a single-slot 6U VMEbus digital input board belonging to VMIC Megamodule product family, providing total 32 optically isolated input channels grouped into four 8-bit ports. Input working voltage supports 5 V,12 V and 24 V field logic levels, selectable via hardware jumpers. Each channel integrates programmable digital de-bounce filter to eliminate transient contact bounce noise. Optical isolator provides 1500 Vrms galvanic isolation between field wiring side and VME backplane logic circuit. Supports 8/16/32 bit VME data transfer modes and A16/A24 address mapping. Onboard Built-In-Test (BIT) hardware performs internal self-check and reports fault status through control status register and front panel fault LED. DIP switch bank sets base address to avoid address conflict in multi-board VME systems. Rugged Eurocard construction, widely used in turbine auxiliary signal monitoring, power plant interlock, aerospace test bench and factory discrete signal acquisition VME chassis.

Working principle

Field digital signals pass through optical isolation diodes to isolate high voltage noise, then go through de-bounce filter before being latched into input register. VME host reads register data to get real-time input state of all channels. BIT circuit can trigger internal test signal for each channel without disconnecting field cables, verify integrity of optocoupler and input circuit. DIP switches define VME base address for register access. VME slave interface completes address decoding and data handshake for host register reading.

Onboard components

4 × 8-bit optocoupler array, programmable de-bounce filter chip bank, input register array, BIT fault detection logic, VME address decode gate array, DIP address switch bank, front panel multi-pin field I/O connector, status LED array, transient surge suppression network.

LED indicators

Front panel LED indicators for board +5 V power supply, BIT fault alarm and VME bus activity. Individual channel status can be acquired via software register read.

Hardware self-diagnosis

Visual inspection of PCB, front ejectors and solder joints; board ID register readback verification; BIT offline channel loopback test; input voltage level switching test; de-bounce filter function validation; VME 8/16/32 bit read/write communication test.

Programming software

VMIC VME device driver library, universal Megamodule I/O configuration and BIT diagnostic utility, compatible with VxWorks, Linux and Windows embedded real-time operating systems.

Electrical & Process Parameters

Model: VME-2528 Device type: 6U VMEbus opto-isolated digital input Megamodule Bus standard: VMEbus, A16/A24 addressing, 8/16/32 bit transfer Channel count: 32 isolated digital input channels, 4 × 8-bit ports Input level: 5 V /12 V /24 V jumper selectable Isolation rating: 1500 Vrms between field and VME backplane Control mode: VME slave access, programmable de-bounce filter, BIT built-in self-test Power supply: +5 V from VME backplane Cooling: Convection cooling Protection: Transient surge suppression, ESD protection, opto-isolation barrier Mounting: Standard 6U VME front panel ejector locking Protection class: PCB with optional conformal coating

Mechanical & Structure

Mounting: Standard single-slot 6U VME Eurocard Protection class: PCB with optional conformal coating

Environmental

Operating temperature: 0℃ ~ +60℃ Storage temperature: -40℃ ~ +85℃ Ambient humidity: 5~95% non-condensing Certification: CE compliant Status: VMIC 32 channel opto-isolated VME digital input board

Installation

Follow ESD safety procedure before handling. Fully power off VME chassis. Insert VME-2528 into vacant 6U VME slot and lock front panel ejector latches. Set DIP switches for VME base address and select field input voltage range. Wire field sensors and interlock contacts to front multi-pin I/O connector. Power on chassis, load VMIC VME driver, configure de-bounce time and run BIT self-test before commissioning.

Interface

VME J1/J2 backplane connector, front panel multi-pin digital input terminal, fault status signal pins.

Diagnostic

Board undetected: poor VME backplane contact, damaged edge connector, incorrect DIP address switch setting. Channel reading stuck low/high: field wiring open/short, optocoupler burnout or input circuit damage. Random signal jitter: de-bounce time set too short or field contact bounce. BIT test failure: optocoupler or BIT diagnostic hardware fault.

Product Brief

VME-2528 VMIC single height 6U VME 32 channel opto-isolated digital input Megamodule,with programmable de-bounce filter and BIT fault detection,for power plant interlock,turbine auxiliary signal monitoring and aerospace test VME systems.