Default Topics and Descriptions

review the following information on default topics and descriptions to review how to guides for topics, see devicehub guides docid\ wxnaso93a33kf0 oxslf2 notes you need to follow the following guidelines for topic names subject based messaging when publishing structured data such as json, you must convert to a byte array (string) first to do this in a flow, you can use the json node important the current topic name generation rule uses a byte specific replacement protocol to create topic names in this system ascii special characters symbols and spaces are replaced with a single underscore (“ ”) since they are represented in 1 byte accented and extended unicode characters characters with accents (e g , “ó”) are replaced by a double underscore (“ ”), reflecting their 2 byte representation the 3 byte and 4 byte unicode characters are replaced with three (“ ”) and four (“ ”) underscores, respectively data publishing formats devicehub collects data from plcs and sends data to a message broker for further distribution data flows trigger using an api call or execute according to a schedule litmus edge supports multiple data formats refer to the following formats used for data in devices raw topics devicehub tags docid\ ckw1ut 55yl7prdysfxjw generate a raw topic, which is a local topic for publishing and subscribing data through the message broker litmus edge publishes each value to a tag specific topic in the following topic format devicehub raw {deviceid} {tagid} device raw topics when you copy a raw topic for a device in litmus edge, the topic is copied in the following format devicehub raw {deviceid} > the ">" character represents a wildcard this means that the topic will be used for any tag associated with the device example of a raw topic devicehub raw\ f7f72687 2f29 46e7 95e2 b5532471ebaa 2d7473c0 83a0 4174 83cc b48a63c1b1cf example of a raw device topic devicehub raw\ 16ac16f7 5e36 4ea0 8d00 17386c051281 > alias topics when you connect a device docid\ ish7bqhzxswtdx8vbnszb , you have the option of using the enable alias topics option if you select to use alias topics for a device, then you won't be able to use raw topics as well each connected device can either use alias topics or raw topics, not both important when alias topics are enabled for a device, you can't use batch write topics to use batch write topics, you must not select the enable alias topics check box in the device configuration see connect a device docid\ ish7bqhzxswtdx8vbnszb and manage devices docid\ esazv soo0efdw5 ivc6y for more information when the enable alias topics check box is selected deviceid in the raw topic format is replaced with devicename tagid in the raw topic format is replaced with tagname alias topics use the following format devicehub alias {devicename} {tagname} example of an alias topic devicehub alias plc2 tag1 write topics write topics write data to a tag specific topic in the following topic format devicehub write {deviceid} {tagid } each device instance on the devicehub write {deviceid} topic receives all messages for the corresponding device the device instance executes a write to the specified tag on the connected device example of a write topic devicehub write f7f72687 2f29 46e7 95e2 b5532471ebaa 2d7473c0 83a0 4174 83cc b48a63c1b1cf batch write topics batch write topics can send multiple write requests simultaneously in the following format devicehub batch write {devicename} or devicehub batch write {deviceid} important only gen 2 drivers can use batch write topics see the industrial systems connection guide docid 8o4ksduafz6jcegj0whs4 to review available gen 2 drivers if enable alias topics is selected in the device configuration, then the devicename and tagname parameters need to be used for setting up batch write topics if enable alias topics is not selected, then deviceid and registerid need to be used see connect a device docid\ ish7bqhzxswtdx8vbnszb and manage devices docid\ esazv soo0efdw5 ivc6y for more information example of a batch write topic devicehub batch write 710b913b b915 4450 9122 8d57e803499b poll once topics poll once topics can be used to trigger a poll to a tag for data in the following topic formats if raw topics are enabled devicehub pollonce {deviceid} {tagid} if alias topics are enabled devicehub pollonce {devicename} {tagname} when a poll once topic is triggered by a message, litmus edge will get data for that tag and publish a message to the raw or alias topic for that tag example of a poll once topic devicehub pollonce f7f72687 2f29 46e7 95e2 b5532471ebaa 2d7473c0 83a0 4174 83cc b48a63c1b1cf topic formats the following table summarizes the types of device level and tag level topics, either with or without aliases you have the option of using raw topics or alias topics 91,302,260 false true unhandled content type unhandled content type false unhandled content type unhandled content type unhandled content type false unhandled content type unhandled content type unhandled content type false unhandled content type unhandled content type unhandled content type false unhandled content type unhandled content type unhandled content type false unhandled content type unhandled content type unhandled content type false unhandled content type unhandled content type unhandled content type false unhandled content type unhandled content type unhandled content type false unhandled content type unhandled content type unhandled content type false unhandled content type unhandled content type unhandled content type false unhandled content type unhandled content type unhandled content type false unhandled content type unhandled content type unhandled content type false unhandled content type unhandled content type unhandled content type false unhandled content type unhandled content type unhandled content type false unhandled content type unhandled content type unhandled content type false unhandled content type