ottlukas opened a new issue, #620: URL: https://github.com/apache/plc4x/issues/620
Hi, I am using plc4x for one of our projects to develop a module which uses plc4x to establish communication with a sensor device using modbus RTU/Serial communication. I am able to communicate with the device with TCP transport but not able to do with RTU/Serial communication. I tried to look for some example/documentation on how to use RTU/Serial communication in plc4x but could not find any information in the website or the web. Also looking at the documentation at [https://plc4x.apache.org/users/protocols/modbus.html](https://plc4x.apache.org/users/protocols/modbus.html) it is not clear whether modbus supports serial transport as it only lists tcp and udp. |Compatible Transports:| * `tcp` (Default Port: 502) * `udp` (Default Port: 502)| Kindly request to clarify if serial is supported in modbus? if so could you please point me to an example/documentation which shall be used to understand how to use it for serial communication. Anyways I tried to use the library/driver plc4j-transport-serial [https://plc4x.apache.org/users/transports/serial.html](https://plc4x.apache.org/users/transports/serial.html) to communicate with device in which the connection is established but it fails to read the data with following WANING. `2021-06-03-18:13:51.814 [nioEventLoopGroup-2-1] WARN io.netty.channel.nio.NioEventLoop - Selector.select() returned prematurely 512 times in a row; rebuilding Selector org.apache.plc4x.java.transport.serial.SerialPollingSelector@28ecdc0d.` `2021-06-03-18:13:59.630 [nioEventLoopGroup-2-1] WARN io.netty.channel.nio.NioEventLoop - Selector.select() returned prematurely 512 times in a row; rebuilding Selector org.apache.plc4x.java.transport.serial.SerialPollingSelector@11c9a1fa.` `My Sample code is as follows.` ` private void plcRtuReader() {` ` // unit-identifier=1&` ` String connectionString =` ` "modbus:serial://COM5?unit-identifier=1&baudRate=19200&stopBits=" + SerialPort.ONE_STOP_BIT` ` + "&parityBits="` ` + SerialPort.NO_PARITY + "&dataBits=8";` ` System.out.println("URL:" + connectionString);` ` try (PlcConnection plcConnection = new PlcDriverManager().getConnection(connectionString)) {` ` if (!plcConnection.getMetadata().canRead()) {` ` System.out.println("This connection doesn't support reading.");` ` return;` ` `} ` PlcReadRequest.Builder builder = plcConnection.readRequestBuilder();` ` builder.addItem("value-2", "input-register:1[2]");` `PlcReadRequest readRequest = builder.build();` `// CompletableFuture<? extends PlcReadResponse> asyncResponse = readRequest.execute();` ` PlcReadResponse response = readRequest.execute().get();` ` for (String fieldName : response.getFieldNames()) {` ` if (response.getResponseCode(fieldName) == PlcResponseCode.OK) {` ` int numValues = response.getNumberOfValues(fieldName);` ` // If it's just one element, output just one single line.` ` if (numValues == 1) {` ` System.out.println("Value[" + fieldName + "]: " + response.getObject(fieldName));` ` `} ` // If it's more than one element, output each in a single row.` ` else {` ` System.out.println("Value[" + fieldName + "]:");` ` for (int i = 0; i < numValues; i++) {` ` System.out.println(" - " + response.getObject(fieldName, i));` ` `} ` `} ` `} ` // Something went wrong, to output an error message instead.` ` else {` ` System.out.println(` ` "Error[" + fieldName + "]: " + response.getResponseCode(fieldName).name());` ` `} ` `} ` System.exit(0);` ` } catch (PlcConnectionException e) {` ` e.printStackTrace();` ` } catch (Exception e) {` ` e.printStackTrace();` ` `} ` `} Thanks a lot for your help. Regards, Purushotham Imported from Jira [PLC4X-300](https://issues.apache.org/jira/browse/PLC4X-300). Original Jira may contain additional context. Reported by: psham81. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@plc4x.apache.org.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
