Ewon Technical Forum

(20-11-2019, 09:13 PM)simon Wrote: [ -> ]Hi,

Thanks for this feedback.

I just figured out that if you call "readMessages()" when the function is called for MQTT connection status changes (event = 1), the system crashes.

So an easy fix is to add
if (event == 1)
  return;

in the MyMQTTClient.java class :

try {
if (event == 1)
return;

MqttMessage msg;

msg = readMessage();
if (msg != null) {
String str = new String(msg.getPayload(), "UTF-8");
System.out.println("MQTT Message Received: " + str);
msg.close();
}
} catch (Exception e) {
System.out.println("Error callMqttEvent: " + e.toString());
}


When event = 0, the event is fired for reading incoming messages. When event = 1, it is because the MQTT status changes (You can then read it with getStatus() ).

Simon

(21-11-2019, 07:20 AM)Kanduri Shouri Wrote: [ -> ]Hello ,
I have tried your code in the zip file . I have ewon flexy 102 series, firmware - 13.2s and javaetk1.4.4 (J2SE) . Now i am trying to publish the float tag in the ewon flexy using java.
In the Real Time Logs ,in the event table its showing me like :

java.lang.NoSuchMethodError: MQTT_Thread: no method readTagAsFloat with signature (Ljava/lang/StringF found in referenced class com.ewon.ewonitf.IOManager or its superclasses

Is any some library is missing that i need to install ? Can you tell me where am i doing wrong.

(21-11-2019, 07:20 AM)Kanduri Shouri Wrote: [ -> ]Hello ,
I have tried your code in the zip file . I have ewon flexy 102 series, firmware - 13.2s and javaetk1.4.4 (J2SE) . Now i am trying to publish the float tag in the ewon flexy using java.
In the Real Time Logs ,in the event table its showing me like :

java.lang.NoSuchMethodError: MQTT_Thread: no method readTagAsFloat with signature (Ljava/lang/StringF found in referenced class com.ewon.ewonitf.IOManager or its superclasses

Is any some library is missing that i need to install ? Can you tell me where am i doing wrong.

(22-11-2019, 12:29 PM)Kanduri ShouriHello ,Can someone help me with the subscriber problem that i mentioned ? Wrote: [ -> ]Thank you simon .i got it . 

Shouri.

(21-11-2019, 07:20 AM)Kanduri Shouri Wrote: [ -> ]Hello ,
I have tried your code in the zip file . I have ewon flexy 102 series, firmware - 13.2s and javaetk1.4.4 (J2SE) . Now i am trying to publish the float tag in the ewon flexy using java.
In the Real Time Logs ,in the event table its showing me like :

java.lang.NoSuchMethodError: MQTT_Thread: no method readTagAsFloat with signature (Ljava/lang/StringF found in referenced class com.ewon.ewonitf.IOManager or its superclasses

Is any some library is missing that i need to install ? Can you tell me where am i doing wrong.

Kanduri,

This function has been implemented in ETK 1.4.4 and in firmware 14.0.(which is temporary unavailable)

Simon

---

Hello Simon ,
Thank you for giving info regarding the previous topic .
I have tried publishing the tags from the ewon device which are coming from the plc to mqtt broker using your java code .
Now i want to control the tags from the other devices to ewon .  For testing i have used mosquitto broker to publish a message to the ewon flexy 102 gateway. and i executed the same program which consists of the subscriber java code by subscribing to the required topic 

All i get  is ,in the realtime events section of the ewon browser, i am just getting received publish log. The message what i published from the mosquitto broker is not printing. I mean  the print function inside the callbackMqtt event is not executing. 

I am not getting whether the callbackMqtt event is being called or not . Because i can see the received publish log , but i am not able to see the message which was published by mosquitto broker .

mosquitto publish message 
         mosquitto_pub -h 192.168.0.50 -t abcdef/PLC_TAGS/CONVEYOR_CONTROL -m "ON"

Ewon Log message:

         Log (16): Client 1922-0017-20 received PUBLISH (d0, q0, r0, m0, 'AXISCADES/PLC_TAGS/CONVEYOR_CONTROL', ... (2 bytes))

Code of MyMQTTClient.java

import com.ewon.ewonitf.IOManager;
import com.ewon.ewonitf.MqttClient;
import com.ewon.ewonitf.MqttMessage;
//import com.ewon.ewonitf.SysControlBlock;

public class MyMQTTClient extends MqttClient {

public MyMQTTClient(String MqttId, String Host) throws Exception {
super(MqttId, Host);
}

public void callMqttEvent(int event) {
//When a message is received through a subscribed topic,
//the function callMqttEvent is called
try {
System.out.println("Reached Call Back Function");
//com.ewon.ewonitf.SysControlBlock Sys = new SysControlBlock(SysControlBlock.INF);
MqttMessage msg = readMessage();
String msgString = new String();

if (msg != null) {
msgString = new String(msg.getPayload(), "UTF-8");
System.out.println("MQTT Message Received: " + msgString);

if(msgString.equalsIgnoreCase("ON")) {
IOManager.writeTag("MACHINE_RUNNING", 1.0);
}
else {
IOManager.writeTag("MACHINE_RUNNING", 0.0);
}
}
msg.close();
}
catch (Exception e) {
System.out.println("Error callMqttEvent: " + e.toString());
}
}
}



I am just receiving the Ewon log message as received publish. But whenever a message is received from the broker to the subscribed topic , this callbackMqtt function should be called automatically and display the message ,but i am not seeing the strings in the print functions of this callbackMqtt() function in the realtime events log or the message which was published .Could you please tell me where i am doing wrong?  
  

(03-12-2019, 04:29 PM)Hello simon,Yes i have subscribed to a topic in MQTT_Thread.java fileand i have tried with  "if (event='=1) return;".  Now i am receiving messages  but i am not able to change the tag data in the ewon gateway . Can you tell me where am i doing wrong? Wrote: [ -> ]- Have you used the script from my post (with "if (event==1) return;") : https://techforum.ewon.biz/thread-586-po...ml#pid3697
- Have you subscribed to a topic to get the message ?

Simon

(03-12-2019, 04:29 PM)simon Wrote: [ -> ]- Have you used the script from my post (with "if (event==1) return;") : https://techforum.ewon.biz/thread-586-po...ml#pid3697
- Have you subscribed to a topic to get the message ?

Simon