Matlab API Subscribe And Poll¶
path (string) = Node path Subscribe to the specified path to receive streaming data or setting data if changed. Use either 'poll' command to obtain the subscribed data.
path (string) = Node path Unsubscribe from the node paths specified via 'subscribe'. Use a wildcard ('*') to unsubscribe from all data.
path (string) = Node path. Note: Wildcards and paths referring to streaming nodes are not permitted. Triggers a single event on the path to return the current value. The result can be fetched with the 'poll' or 'pollEvent' command.
ziDAQ('poll', duration, timeout, [flags]);
duration (double) = Time in [s] to continuously check for value changes in subscribed nodes before returning timeout (int64) = Poll timeout in [ms]; recommended: 10 ms [flags] (uint32) = Flags specifying data polling properties Bit FILL : Fill data loss holes Bit THROW : Throw if data loss is detected (only possible in combination with DETECT). Bit DETECT: Just detect data loss holes. Continuously check for value changes (by calling pollEvent) in all subscribed nodes for the specified duration and return the data. If no value change occurs in subscribed nodes before duration + timeout, poll returns no data. This function call is blocking (it is synchronous). However, since all value changes are returned since either subscribing to the node or the last poll (assuming no buffer overflow has occurred on the Data Server), this function may be used in a quasi-asynchronous manner to return data spanning a much longer time than the specified duration. The timeout parameter is only relevant when communicating in a slow network. In this case it may be set to a value larger than the expected round-trip time in the network.
result = ziDAQ('pollEvent', timeout);
timeout (int64) = Poll timeout in [ms] Return the value changes that occurred in one single subscribed node. This is a low-level function. The poll function is better suited in nearly all cases.