The bus latency of an Ocelot and modules like the SECU16 don't allow it to count very fast. I would say that anything that exceeds more then one pulse every 1.5 to 2 seconds risks losing some events. This is especially true if you have several modules on your adnet bus, because each individual module is polled a bit less often per second. A device like a anemometer would likely put out many pulses per second (typically at least one per shaft revolution).
This would be a good microcontroller project however!