Description
VMIC VMIVME-2540-000
I. Basic Information
Model: VMIVME-2540-000
Brand: VMIC (GE Fanuc, Abaco Systems)
Product Line: 6U VME bus slave intelligent counter & controller board, equipped with on-board local CPU and multi-channel high-precision timing chips. It realizes high-speed event counting, frequency/pulse width measurement, quadrature encoder position acquisition, pulse train generation and programmable discrete output, widely applied in precision motion measurement, power plant test systems, rail transit positioning and industrial timing control.
Product Positioning
VMIVME-2540-000 is a dedicated intelligent I/O measurement and control board for VME architecture, equipped with a 15MHz 68HC000 local processor. It independently completes multi-channel signal preprocessing, data caching and timing interrupt triggering without frequent host polling. Configurable to 4/8/16/24 channels via onboard jumpers, it adopts AM9513A timing controller array to support 32-bit high-speed counting, high-precision period measurement and quadrature position decoding. It can collect encoder, speed and flow pulse signals, as well as output servo stepping pulses and timing switch signals, effectively reducing VME bus load and ensuring real-time performance of high-speed signal acquisition.
Hardware Architecture
Standard 6U Eurocard flame-retardant PCB with three-proof coating, consisting of four core units:
- Local Main Control Unit: 15MHz 68HC000 16-bit processor with solidified firmware, realizing command configuration, hardware fault latch and watchdog monitoring.
- Timing & Counting Array Unit: 6 pieces of AM9513A STC chips, 24 independent channels supporting TTL single-ended / RS-422 differential input, with programmable trigger edge and hardware filter.
- VME Slave Bus Interface: Compliant with VME Rev.C.1, supports A24/A32 addressing, multi-bit data transmission, DIP switch configurable base address and IRQ1~IRQ7 interrupt priority, dual-level bus access permission.
- Front I/O Protection Interface: High-density connector with ESD/EFT surge protection, level conversion and differential receiving circuit, adapting to long-distance industrial signal transmission.
Mounting Specification
Vertical single-slot snap-in installation on 19-inch 6U VME rack, compatible with all series of VME master and I/O daughter boards. It has passed IEC anti-vibration, humidity cycling and wide-temperature aging reliability tests, with standardized dimensions for direct spare replacement.Dimension (H×W×D): 233.35mm × 160mm × 25mm, net weight: 0.48kg.
Compatible Systems
- Hardware: Standard 6U VME chassis, MVME/VMIVME series VME single board computers, twisted shielded signal cables, front terminal adapter boards;
- Software: VxWorks/QNX/Linux real-time OS, VME bus driver, IOWorks configuration tool;
- Field Devices: Incremental quadrature encoders, speed sensors, flow meters, limit switches, servo drives;
- Application Industries: Thermal & hydropower test measurement, rail transit interlock, precision automatic production lines, aerospace test platforms, metallurgical rolling line closed-loop position control.
Product Characteristics
- Flexible channel configuration of 4/8/16/24 modes, independent parameter programming per channel for diversified measurement and control demands;
- Onboard local CPU supports continuous autonomous measurement, batch data caching to reduce VME bus bandwidth occupation and avoid pulse loss;
- Integrated six core functions: event counting, frequency measurement, pulse width acquisition, quadrature positioning, pulse generation and discrete output;
- Dual TTL/RS-422 differential input supports long-distance anti-interference transmission, maximum 2.5MHz high-frequency stable signal acquisition;
- IEEE754 32-bit floating-point & integer dual data format ensures high measurement precision and low transmission delay;
- Industrial wide-temperature three-proof design with CE & UL certification for 7×24h unattended continuous operation.
II. Technical Specifications
2.1 Electrical Parameters
- VME Backplane Power: +5VDC, typical power consumption 5.6W, max operating current 1120mA
- Signal Level: TTL single-ended, RS-422 differential, 1.4V reference threshold
- Port Withstand Voltage: 500VAC/1min between I/O ports and ground, ±4kV ESD, ±2kV EFT surge protection
- Interrupt: Programmable IRQ1~IRQ7 VME vector interrupt, triggered by event or timing task.
2.2 Measurement & Calculation Parameters
- Onboard Processor: 15MHz 68HC000 16-bit microprocessor
- Max Event Count: 4G (32-bit unsigned)
- Frequency Range: 1.16mHz ~ 2.5MHz
- Pulse Width Measurement: 400ns ~ 8.59×10⁶s (32-bit float); 400ns ~ 858s (32-bit integer)
- Pulse Output: 0.0076Hz ~ 2.5MHz, programmable pulse quantity and duty cycle
- Quadrature Encoder: Max 1MHz, 32-bit counter with limit & modulo check
- Timing Interrupt Range: 0.0076Hz ~ 1000Hz
2.3 Bus & Channel Parameters
- VME Standard: VMEbus Rev.C.1, A24/A32 addressing, D8/D16/D24/D32 data width
- Local Address Window: 64KB, base address configured via DIP switch
- Channel Mode: Hardware jumper selectable 4/8/16/24 channels
- Data Format: IEEE754 32-bit float, 16/32-bit signed/unsigned integer.
2.4 Environmental Specifications
- Operating Temperature: 0℃ ~ +60℃; rugged version: -40℃ ~ +85℃
- Storage & Transport Temperature: -40℃ ~ +85℃
- Relative Humidity: 5%～95%RH, non-condensing, no corrosive gas or heavy dust
- Vibration Standard: IEC 60068-2-6, 0.7g continuous vibration horizontally & vertically
- EMC Compliance: IEC61000-6-2 industrial immunity standard
- Protection Class: Bare board IP20, IP30 in sealed metal control cabinet.
2.5 Mechanical Parameters
- Form Factor: Standard 6U VME (233.35mm × 160mm × 25mm)
- Net Weight: 0.48kg
- Mounting: Vertical snap-in installation on 19-inch VME rack with anti-loose front lock lever
- PCB: FR4 V0 flame-retardant material with full-area three-proof coating
- Interfaces: Front high-density I/O connector, rear 96-pin gold-plated VME P1 connector.
III. Key Features
3.1 Multi-Channel High-Speed Pulse Acquisition
Each channel can be independently configured for event, frequency or pulse width measurement with hardware anti-jitter filtering. It supports 2.5MHz high-frequency pulse capture and 32-bit long-term cumulative counting, uploading cached data in batches to avoid pulse loss caused by frequent host polling.
3.2 High-Precision Quadrature Position Decoding
Supports sin/cos incremental encoder signals up to 1MHz, 32-bit real-time position register with overflow and limit check, widely used in rolling mill gap positioning, gantry coordinate control and travel monitoring.
3.3 Programmable Pulse & Discrete Timing Output
Custom pulse train output drives servo positioning; 24-channel discrete outputs realize sequential equipment startup, solenoid valve control and alarm contact driving with millisecond-level precise timing via onboard timer.
3.4 Autonomous Continuous Measurement & Interrupt Reporting
In continuous measurement mode, the local CPU runs data collection and caching independently, uploading datasets to the host via VME interrupt only when the buffer is full or events occur, greatly reducing bus load and ensuring system real-time performance.
3.5 Flexible Bus Configuration & Hardware Self-Diagnosis
DIP switches configure base address, interrupt number and access permission to support multi-board parallel deployment without conflict. Power-on full-channel self-test locks fault information for rapid anomaly location.
IV. Working Principle
After VME power-on, the host configures the board’s address, interrupt and channel parameters, and the onboard 68HC000 initializes all STC timing chips. Field pulse and encoder signals are filtered and converted before entering high-speed counting channels for frequency, period and position calculation. Measurement data is cached locally, and the board triggers VME interrupt for batch data upload when tasks are completed. Pulse output is generated by timing chips according to preset parameters, and hardware isolation protects the board from industrial electromagnetic interference to realize long-term stable measurement and control.
V. Application Scenarios
- Thermal & Hydropower Plants: Turbine speed pulse collection, valve encoder position monitoring, auxiliary equipment event counting and thermal test high-precision parameter acquisition;
- Rail Transit: Switch position collection, train speed measurement, signal equipment event statistics and interlock timing control;
- Precision Machinery Production Lines: CNC servo positioning, winding tension speed counting and workpiece trigger event acquisition;
- Aerospace Laboratory Test Platform: Multi-sensor pulse batch collection, motion mechanism high-precision positioning and fatigue test cycle counting;
- Legacy VME System Renovation: Direct replacement of faulty counter boards, fully compatible with original chassis, wiring and driver programs.
