MQTT Publish Error

IoT Modules LTE Standard Module
1

Dear All,

when I try to publish 500 Bytes of data to the MQTT Server at every 400ms, the AT+QMTPUB command gives error at alternates interval like below.

I think it is delay problem, like when I publish data after 500ms the command gives OK. But when I publish data at less then 500ms interval it gives ERROR.

I can’t understand why it is happening. According to hardware manual the UL has 5 Mbps speed and I am sending only 500 Bytes of data.

Please anybody have solution then please tell me.

If you have any questions then please ask me.

[2023-09-23_13:08:51:995]
[2023-09-23_13:08:51:995]>
[2023-09-23_13:08:52:042]OK
[2023-09-23_13:08:52:493]
[2023-09-23_13:08:52:493]>
[2023-09-23_13:08:52:540]ERROR
[2023-09-23_13:08:52:784]
[2023-09-23_13:08:52:784]+QMTPUB: 0,1,0
[2023-09-23_13:08:52:987]
[2023-09-23_13:08:52:987]>
[2023-09-23_13:08:53:050]OK
[2023-09-23_13:08:53:489]
[2023-09-23_13:08:53:489]>
[2023-09-23_13:08:53:549]ERROR
[2023-09-23_13:08:53:745]
[2023-09-23_13:08:53:745]+QMTPUB: 0,1,0
[2023-09-23_13:08:53:989]
[2023-09-23_13:08:53:989]>
[2023-09-23_13:08:54:037]OK
[2023-09-23_13:08:54:501]
[2023-09-23_13:08:54:501]>
[2023-09-23_13:08:54:501]ERROR
[2023-09-23_13:08:54:742]
[2023-09-23_13:08:54:742]+QMTPUB: 0,1,0
[2023-09-23_13:08:54:922]
[2023-09-23_13:08:54:922]>
[2023-09-23_13:08:54:922]OK
[2023-09-23_13:08:55:362]
[2023-09-23_13:08:55:362]>
[2023-09-23_13:08:55:408]ERROR
[2023-09-23_13:08:55:456]
[2023-09-23_13:08:55:456]>
[2023-09-23_13:08:55:502]OK
[2023-09-23_13:08:55:549]
[2023-09-23_13:08:55:549]>
[2023-09-23_13:08:55:627]ERROR
[2023-09-23_13:08:55:627]+QMTPUB: 0,1,0
[2023-09-23_13:08:55:986]
[2023-09-23_13:08:55:986]>
[2023-09-23_13:08:56:049]ERROR
[2023-09-23_13:08:56:221]
[2023-09-23_13:08:56:221]+QMTPUB: 0,1,0
[2023-09-23_13:08:56:487]
[2023-09-23_13:08:56:487]>
[2023-09-23_13:08:56:549]OK
[2023-09-23_13:08:56:982]
[2023-09-23_13:08:56:982]>
[2023-09-23_13:08:57:046]ERROR
[2023-09-23_13:08:57:301]
[2023-09-23_13:08:57:301]+QMTPUB: 0,1,0
[2023-09-23_13:08:57:489]
[2023-09-23_13:08:57:489]>
[2023-09-23_13:08:57:535]OK
[2023-09-23_13:08:57:989]
[2023-09-23_13:08:57:989]>
[2023-09-23_13:08:58:035]ERROR
[2023-09-23_13:08:58:270]
[2023-09-23_13:08:58:270]+QMTPUB: 0,1,0
[2023-09-23_13:08:58:489]
[2023-09-23_13:08:58:489]>
[2023-09-23_13:08:58:535]OK
[2023-09-23_13:08:58:996]
[2023-09-23_13:08:58:996]>
[2023-09-23_13:08:59:043]ERROR
[2023-09-23_13:08:59:261]
[2023-09-23_13:08:59:261]+QMTPUB: 0,1,0
[2023-09-23_13:08:59:496]
[2023-09-23_13:08:59:496]>
[2023-09-23_13:08:59:496]OK

Thanks

2

Please find below my AT Commands sequence.

ATE0
AT+CSQ
AT+QICSGP=1,1,“APN”,“”,“”,1
AT+QMTOPEN=0,“mqtt-dashboard.com”,1883
AT+QMTCONN=0,“ClientID”,“”,“”

below process repeats every 400ms
{
AT+QMTPUB=0,1,1,0,“helloWorld/Topic1”
500 Byte data
}

3

Please increase the delay such as 1s and try again

4

Dear Herbert,

Thanks for reply.

If I increase the delay then I can’t send my data at 400ms time interval. So can you suggest another solution?

Thanks

5

Since the underlying protocol of MQTT is TCP, the acknowledgement frame ack needs to be received after sending data, so the network delay may affect the receiving of ack. I recommend that you use the UDP protocol for testing