Abaco Systems / VMIC VMIVME-3126A-100 High Resolution Isolated A/D Converter Board

The Abaco Systems VMIVME-3126A-100 is a high-resolution isolated analog-to-digital converter board for VMEbus systems. It delivers simultaneous sampling across 8 or 16 isolated input channels with 16-bit resolution and 1,500 VDC input-to-input isolation. The board supports software-configurable voltage (±50 mV to ±10 V, or optional ±5 mV to ±1 V) and current modes, with dedicated 24-bit ADCs per channel and real-time DSP-based calibration and filtering.

– Technical Specifications

Analog Input Channels
• 8 or 16 isolated input channels with active guards
• Dedicated 24-bit ADC per channel
• Input-to-input and input-to-VMEbus isolation: 1,500 VDC (1,000 VAC)

Input Ranges
• Voltage Mode: ±50 mV to ±10 V (standard) or ±5 mV to ±1 V (optional), software-selectable per channel
• Current Mode: 400 Ω termination resistor
• RTD Excitation: 200 mA/400 mA per channel, software-controlled
• Open transducer detection supported

Data Acquisition
• Resolution: 16 bits user-available data
• Simultaneous sampling across all inputs
• Channel sample rate: 100 SPS per channel
• Maximum aggregate sample rate: 1,600 SPS (16-channel) / 800 SPS (8-channel)
• Integral non-linearity: ±0.005% maximum

Signal Processing
• On-board DSP performs 32-bit arithmetic calibration and filtering
• Real-time offset and gain correction
• E2PROM calibration coefficient storage
• Software-controlled bandwidth: 0.05 to 26 Hz (6-pole low-pass filters)

VMEbus Interface
• A24 or A16 address space (jumper-selectable)
• Supervisory or user privilege modes
• DTB Slave: D16/D8 (EO)
• Data buffer: 16 contiguous 16-bit words
• Access time: 400 ns (DS to DTACK)

Physical
• Double height Eurocard (6U): 160 × 233.35 mm
• Weight: 700 g maximum
• Input connectors: Two 64-pin DIN connectors

– Key Features

• Per-channel dedicated ADCs eliminate cross-talk and enable true simultaneous sampling
• Galvanic isolation protects instrumentation from transients and high-voltage environments
• DSP-based calibration eliminates mechanical trimpots and drift over temperature
• Channel-by-channel input range selection enables measurement optimization for low-level and high-level signals
• Open transducer detection improves system diagnostics

– Typical Applications

• Industrial process monitoring and control requiring noise immunity
• Laboratory data acquisition systems with multichannel requirements
• High-voltage transducer interface in power distribution systems
• RTD and resistance measurement in isolated environments

– Compatibility & Integration

The board integrates into standard 6U VMEbus crates and supports both A16 and A24 addressing modes, allowing flexible system architecture in legacy and modern VME deployments.