MAN0974-14-EN_XL7_XL7P_UM
July 6, 2022
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9.3
High Speed Counter (HSC) Functions
The XL7/XL7 PRIME supports two very high speed, configurable counters. There are four dedicated
inputs that can be configured to a number of different options. Each of the two counters can run in one
of five modes. Those modes are Totalizer, Frequency Counter, Pulse Width Measurement, Period
Measurement and Quadrature measurement. For some modes, more than one HSC input may be
consumed. The measurement values are provided to ladder in a %AI register. Refer to the
chapter for more details.
9.3.1 Frequency
In frequency mode, the frequency of the input signal is written to the accumulator in terms of Hertz
(cycles/second). When using frequency mode, four update selections are provided which specify the
width of the sample window.
NOTE:
Selecting a shorter sample window provides a quicker measurement (faster response) but lowers
the frequency accuracy (resolution) and increases the minimum frequency measurement limit. In this
mode the Disable and Latch special functions are allowed. Refer to the
these functions.