ES441 – Counter and Frequency Module

The ES441 module is able to derive multiple types of measurement signals simultaneously from the same physical input – all signals are provided with identical time stamps. The multipurpose use of one input channel significantly reduces the effective cost per channel when more than one signal type is required. To support typical automotive specific applications, the measurement of the average rotational speed is supported for many different types of components, such as camshafts, crankshafts, fans, and turbines. Rotational speed can be used to calculate the vehicle speed or flow rates.

Two different thresholds are used for switching from the active to the inactive level and vice versa (hysteresis). The difference between the threshold levels determines the range of noise suppression. The adjustment of the hysteresis value relative to the noise level of the incoming signals provides an efficient and convenient means to enhance the quality of the measurement signals. Additionally, a software configurable glitch filter can be deployed to eliminate spikes caused by bouncing effects of switches.

Functions at a glance

  • 4 electrically isolated digital input channels
  • Concurrent counter, frequency, duty cycle, state, and time interval measurements
  • Resolves 4 MHz signal frequencies / 120 ns pulse widths
  • Input voltage range of ±50 V
  • Adjustable sensor supply voltages per channel from 5 V to 15 V
  • Operating temperature from -40 °C to 120 °C (-40 °F to 248 °F)
  • Rugged waterproof and dustproof housing (IP67)