Vansco VMM3120, User Manual

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User Guide 35
Outputs
You should use as much filtering as possible on the low-side output's current
measurement to prevent anomalous analog readings in noisy environments. The
amount of filtering (cut-off frequency) for your hardware filter will depend on the
rate at which the current changes, as well as the expected response time of your
system. Filtering of less than 7 Hz is not permitted, as it will have an adverse
effect on overcurrent and short-circuit protection times. If an application requires
a cutoff frequency lower than 7 Hz, a filter can be implemented in the application
software.
To prevent aliasing, filter at half the rate of your sampling rate, according to the
Nyquist criterion. If you require more filtering, a software filter can be added to
your system. For example, if a current reading needs to be sampled at a rate of 20
Hz, the cutoff frequency for the filter should be 10 Hz.
The following diagram shows the configuration options for low-side outputs:
Figure 16: Low-side outputs with current sense configuration options