Apache IotDB

Apache IoTDB is database for storing time serie data. Therefore, it can be a good solution for managing the data which is collected by PLC4x.

Data Model (Concept)

Given a PLC address and some fields, we can consider the PLC as a device in IoTDB, and each field as a measurement in IoTDB. A couple of PLCs form a storage group.

For example, there is a virtual storage group mi, and a PLC d1, which has one field RANDOM/foo:Integer. Then, in IoTDB, we can get a time series like root.mi.d1.foo (or root.mi.d1.RANDOM_foo_Integer, as you like). Then, we can write data into IoTDB using JDBC with SQL or native API called session API.

Example

https://github.com/apache/plc4x/tree/develop/plc4j/examples/hello-integration-iotdb shows an example to collect data using PLC4x and then writing data to IoTDB.

To run the java example, some arguments are needed:

e.g., java -jar ….. --connection-string simulated://127.0.0.1 --field-address RANDOM/foo:Integer --polling-interval 1000 --iotdb-address 127.0.0.1:6667 --iotdb-user-name root --iotdb-user-password root --iotdb-sg mi --iotdb-device d1 --iotdb-datatype INT32 --use-jdbc false

Then PLC4x will collect data from a simulated PLC device, which generate random integer per 1 second. IoTDB’s address is 127.0.0.1 and the port is 6667. The data will be stored in device root.m1.d1, and the measurement name is RANDOM_foo_Integer.

If you are using IoTDB v0.10.0 with the default configuration, and do not manually create the above time series, then IoTDB will consider the data as float. So, after running the program a few secondes, you can query the data using IoTDB’s command line: select * from root.mi.d1;

+-----------------------------+-----------------------------+
|                         Time|root.mi.d1.RANDOM_foo_Integer|
+-----------------------------+-----------------------------+
|2020-07-16T20:01:39.216+08:00|                -1.34242598E9|
|2020-07-16T20:01:40.150+08:00|                 -9.4141104E7|
|2020-07-16T20:01:41.154+08:00|                 1.40969664E9|
|2020-07-16T20:01:42.155+08:00|                  9.5824531E8|
|2020-07-16T20:01:43.157+08:00|                  -4.207406E7|
+-----------------------------+-----------------------------+

The detailed usage about IoTDB can be found https://iotdb.apache.org/UserGuide/Master/Client/Programming%20-%20Native%20API.html