P635
PXI Frequency Counter Module

The P635 is a single-width, 3U, PXI module with eight frequency measurement channels. This counter module can be used to monitor a variety of pulse sources. Moreover, its unique circuitry allows the monitoring of a wide range of frequencies without changing any module settings. TTL inputs are provided as well as differential input circuits with filtering and hysteresis to provide high noise immunity. The switching threshold is programmable, and the input voltage should be at least twice the threshold voltage for noise immunity. AC or DC coupling of the differential inputs is programmable on a per-channel basis.

PXI Frequency Counter Module: P635

P635 Data Sheet

Supporting Software

Supporting Chassis

US Price/CH Start at: $501

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The internal clock for the module is driven from a 10 MHz clock having a 1 ppm accuracy from 10°C to 50°C. The internal clock can be set to 1 MHz or 10 MHz under program control. The 10 MHz clock provides an order of magnitude increase in counting resolution over the 1 MHz clock and is the general choice. The only disadvantage of the 10 MHz clock is that it causes a faster rollover of the tick count and limits the lowest frequency to be measured to 0.6 Hz, compared to 0.06 Hz when the 1 MHz clock is used.

PXI Module Features

  • 8 Frequency Counter Channels
  • Frequency Range from 0.06 Hz to 100 kHz
  • Differential & TTL Inputs Provided
  • Differential Input Range 20 mV to 20 V
  • Programmable SAC/DC Differential Inputs
  • Programmable Observation Window: 1 ms to 1.025 sec
  • Precision Time Base (1 ppm, 10°C to 50°C)
  • Programming-Free Operation with SoftView

PXI Module Ordering Information

P635 Products and Part Numbers
8 Channel, 100 kHz Frequency Counter,
±20-200mV to ±20V Range,
3U Single-Width PXI Module
P635-AA21
8 Channel, 100 kHz Frequency Counter,
±100-1000mV to ±20V Range,
3U Single-Width PXI Module
P635-AB21