Abaco Systems / VMIC VMIVME-2536-000 32-Channel Optically Coupled Digital I/O Board

The Abaco Systems/VMIC VMIVME-2536-000 is a 32-channel optically coupled digital I/O board for VMEbus systems, delivering galvanic isolation between field signals and the VME chassis. The board provides 32 optically isolated inputs and 32 optically isolated outputs with configurable voltage ranges, making it suitable for industrial automation, data acquisition, and process control where signal integrity and noise immunity are critical.

Technical Specifications

• 1 kV sustained isolation to VME backplane


• 3.5 kV pulsed isolation (field to VMEbus)


• 500 V sustained channel-to-channel isolation (maximum)


• 10 MΩ minimum input and output isolation resistance Data Transfer & Addressing


• Supports 8-, 16-, and 32-bit data transfers


• Standard data or short I/O addressing (A16 or A24)


• VMEbus compliance: ANSI/IEEE STD 1014-1987, IEC 821 and 297


• Address modifiers: 3D, 39/2D, 29 Input Specifications


• Optically coupled voltage or contact sensing inputs


• Configurable voltage ranges: 5 V, 12 V, 24-28 V, 48 V, 125 V


• 5 V option: VINH 2.6 V typ., VINL 1.8 V typ.; 3.5 mA typ. input current


• 24-28 V option: VINH 12.9 V typ., VINL 6.9 V typ.; 2.8 mA typ. input current


• 48 V option: VINH 27.0 V typ., VINL 13.9 V typ.; 2.2 mA typ. input current


• 125 V option: VINH 75.2 V typ., VINL 48.2 V typ.


• Selectable input debounce timer: 0, 256, 512, 1.024, 2.048, 4.096, 8.192, 16.384 ms (0 ms default)


• Contact sensing power selectable on byte boundaries: external voltage or VMEbus +5 V Output Specifications


• Optically coupled open-collector outputs


• Output voltage: 50 V maximum


• Current sinking: 300 mA (maximum)


• Output leakage current: 500 µA maximum at VCE = 50 V, TA = 60 °C


• User-installable pull-up resistors; configurable on byte boundaries Built-in Test (BIT)


• Online and offline BIT for inputs and outputs


• Input BIT via onboard test registers mapped to input data ports


• Output BIT disables outputs in offline mode; data patterns readable without affecting outputs


• Board initializes in test mode on power-up or reset Form Factor


• Double Eurocard (6U single slot)