Abaco Systems / VMIC VMIVME-3125-000 32-Channel 12-Bit A/D Converter Module

The Abaco Systems VMIVME-3125-000 is a 12-bit analog-to-digital converter module for VMEbus systems delivering 40 kSPS minimum aggregate conversion rate. It accommodates 32 single-ended or 16 differential analog input channels with selectable voltage ranges (±5 V, ±10 V, 0 to +10 V) and current inputs (0-20 mA, 4-20 mA, 5-25 mA). Jumper-selectable programmable gain amplifiers provide x1, x10, or x100 gains, enabling signal conditioning across ±50 mV to ±10 V input spans.

The module features autoscanning capability that continuously digitizes inputs and stores results in dual-ported data registers for direct VMEbus access without software intervention. Built-in-test functionality validates PGA, ADC, and control logic operation in real time. Input isolation of 1,000 V analog-to-digital ground, 10 MΩ minimum input impedance, and ±40 V overvoltage protection ensure signal integrity in demanding industrial and scientific applications.

Software-selectable offset binary or two's complement data coding accommodates diverse processing requirements. Standard 50 kHz low-pass filtering with optional 40 Hz cutoff addresses noise rejection across frequency domains. Accuracy specification of ±0.04% reading ±0.03% range ±2.0 supports precision measurement tasks.

Technical Specifications

• Form Factor: 6U Eurocard


• ADC Resolution: 12 bits


• Conversion Rate: 40 kSPS minimum aggregate


• Analog Input Channels: 32 single-ended or 16 differential


• Voltage Input Ranges: ±5 V, ±10 V, 0 to +10 V (selectable); ±50 mV to ±10 V with PGA


• Current Input Ranges: 0-20 mA, 4-20 mA, 5-25 mA


• Programmable Gain: x1, x10, x100 (jumper-selectable)


• Input Impedance: 10 MΩ minimum (line-to-line and line-to-common)


• Common-Mode Voltage: ±11 V maximum (differential inputs, referenced to analog ground)


• CMRR: ≥90 dB (x100 gain); ≥72 dB (x1 gain)


• Input Noise (10-1000 Hz at 3σ): 300 µVp-p (x100 gain), 1.0 mVp-p (x10 gain), 4.0 mVp-p (x1 gain)


• Overvoltage Protection: ±40 V sustained (powered), ±25 V (unpowered), ±40 V transient (1 second)


• Input Filtering: 50 kHz standard (-3 dB); optional 40 Hz (-3 dB)


• Input Isolation: 1,000 V analog GND/digital GND


• Accuracy: ±0.04% reading ±0.03% range ±2.0


• Data Coding: Offset binary or two's complement (software-selectable)


• Built-In-Test: Real-time BIT for PGA, ADC, and control logic

Key Features

• Dual-ported data registers enable VMEbus access without software polling


• Autoscanning continuously digitalizes all channels


• 1,000 V input isolation protects digital circuitry


• Selectable current termination resistors (250 Ω or 500 Ω at 0.01%)


• Pull-down resistors (~22 MΩ) prevent floating inputs

Typical Applications

• Industrial data acquisition systems


• Scientific instrumentation and laboratory measurement


• VMEbus embedded systems requiring multi-channel signal conditioning


• Real-time monitoring with integrated self-test capability

Compatibility & Integration

• VMEbus interface (6U Eurocard form factor)


• Compatible with VMIVME-3125 product family