The DynamicSignals/Kinetic Systems V635-AA21 is an 8-channel frequency counter that measures input signals from 0.01 Hz to 100 kHz with high precision and minimal configuration overhead. This single-width, C-size VXIbus module delivers consistent performance across its frequency range and operates in both single-scan and continuous modes. The counter employs differential input circuits with integrated filtering and hysteresis to reject noise, while programmable switching thresholds and per-channel AC/DC coupling options adapt to diverse signal sources.
## Technical Specifications
• **Channels:** 8
• **Frequency Range:** 0.01 Hz to 100 kHz
• **Input Voltage Range:** 20 mV to 20 V peak-to-peak (differential inputs)
• **Input Coupling:** Programmable AC or DC per channel
• **Observation Window:** 1 ms to 1.024 s
• **Clock Rate Options:** 1 MHz or 10 MHz (programmable)
• **Clock Accuracy:** ±0.0001%
• **Time Base Accuracy:** ±1 ppm (10°C to 50°C)
• **Counting Accuracy:** ±0.01% (10 ms window, 1 MHz clock); ±0.001% (10 ms window, 10 MHz clock); improves with longer observation windows
• **Power Supply:** 103.5–126.5 VAC or 207–253 VAC, 50–60 Hz
## Key Features
• Differential input circuitry with programmable switching threshold
• Filtering and hysteresis for high noise immunity
• TTL inputs available on D connector options
• BNC input connectors supported
• Static and dynamic configuration modes
• Register-based VXIbus architecture
• Data access via A32/A16 and D32/D16 transfers through Offset Register
## Typical Applications
• Shaft encoder monitoring for engine RPM measurement (automotive and jet aircraft)
• Flow meter measurement
• General-purpose pulse monitoring
## Compatibility & Integration
The V635-AA21 operates as a register-based VXIbus module compatible with standard VXIbus mainframes such as the V195-AA21. Configuration and data retrieval use standard VXIbus memory-mapped I/O addressing.
