The Modbus connector keeps throwing errors and disconnecting; what could be the reason?

[DuXiaoChuang]

The Modbus connector keeps throwing errors and disconnecting; what could be the reason? Below is the log:
"-10-15 09:56:00.155 - |INFO| - [modbus_connector.py] - modbus_connector - init - 99 - Starting Modbus Connector...2025-10-15 09:56:00.261 - |INFO| - [slave.py] - slave - connect - 230 - Connected to Shenyang Machine Tool T5-500Q-0032025-10-15 09:56:26.786 - |INFO| - [modbus_connector.py] - modbus_connector - init - 99 - Starting Modbus Connector...2025-10-15 09:56:26.878 - |INFO| - [slave.py] - slave - connect - 230 - Connected to Shenyang Machine Tool T5-500Q-0032025-10-15 09:57:29.890 - |INFO| - [modbus_connector.py] - modbus_connector - close - 157 - modbus has been stopped2025-10-15 09:58:03.441 - |INFO| - [modbus_connector.py] - modbus_connector - init - 99 - Starting Modbus Connector...2025-10-14 15:19:38.254 - |ERROR| - [modbus_connector.py] - modbus_connector - __poll_device - 327 - Device Shenyang Machine Tool T5-500Q-003 is not connected, cannot connect to server, skipping reading..."

[samson0v]

Hi @DuXiaoChuang, thanks for your interest in ThingsBoard IoT Gateway!
What version of the gateway are you using?
How are you running the gateway, via docker?
Have you tried reading the device with another software (modpoll)?
What does your screenshot show?
Please send the Modbus connector config, as well as the DEBUG logs.

[DuXiaoChuang]

Hi @DuXiaoChuang, thanks for your interest in ThingsBoard IoT Gateway! What version of the gateway are you using? How are you running the gateway, via docker? Have you tried reading the device with another software (modpoll)? What does your screenshot show? Please send the Modbus connector config, as well as the DEBUG logs.

VERSION = "3.7.6"，I running the gateway via Windows. I Used reading the device with modpoll is normal.
Modbus connector config：
{
"master": {
"slaves": [
{
"host": "192.168.40.3",
"port": 502,
"type": "tcp",
"method": "socket",
"timeout": 35,
"baudrate": 19200,
"stopbits": 1,
"bytesize": 8,
"parity": "N",
"strict": true,
"repack": false,
"delay_between_requests_ms": 0,
"byteOrder": "BIG",
"wordOrder": "LITTLE",
"retries": true,
"retryOnEmpty": true,
"retryOnInvalid": true,
"pollPeriod": 500,
"unitId": 1,
"deviceName": "\u6c88\u9633\u673a\u5e8aT5-500Q-001",
"sendDataOnlyOnChange": true,
"connectAttemptTimeMs": 5000,
"connectAttemptCount": 5,
"waitAfterFailedAttemptsMs": 300000,
"attributes": [
{
"tag": "CNC\u578b\u53f7",
"type": "string",
"functionCode": 3,
"objectsCount": 5,
"address": 63001
},
{
"tag": "\u6709\u6548\u8f74\u6570",
"type": "16int",
"functionCode": 3,
"objectsCount": 1,
"address": 63013
},
{
"tag": "\u4e0a\u7535\u6b21\u6570",
"type": "32int",
"functionCode": 3,
"objectsCount": 2,
"address": 63030
},
{
"tag": "\u673a\u5e8a\u7f16\u53f7",
"type": "string",
"functionCode": 3,
"objectsCount": 5,
"address": 63060
},
{
"tag": "\u8f74\u4f3a\u670d\u4fe1\u606f",
"type": "string",
"functionCode": 3,
"objectsCount": 1,
"address": 63100
},
{
"tag": "\u4e3b\u8f74\u4f3a\u670d\u4fe1\u606f",
"type": "string",
"functionCode": 3,
"objectsCount": 1,
"address": 63500
}
],
"timeseries": [
{
"tag": "CNC_AlarmNo",
"type": "16int",
"functionCode": 3,
"objectsCount": 1,
"address": 64503,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_AlarmMsg",
"type": "string",
"functionCode": 3,
"objectsCount": 4,
"address": 64507,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearXSpeed",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62370,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_FeedRate",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62372,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearXPosition",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62200,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearYPosition",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62202,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearZPosition",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62204,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_ToolNo",
"type": "16int",
"functionCode": 3,
"objectsCount": 1,
"address": 62360,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearYSpeed",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62370,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearZSpeed",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62370,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_SpindleRate",
"type": "double",
"functionCode": 3,
"objectsCount": 2,
"address": 62395,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_SpindleSpeed",
"type": "double",
"functionCode": 3,
"objectsCount": 2,
"address": 62385,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_OperateMode",
"type": "32int",
"functionCode": 3,
"objectsCount": 2,
"address": 62406,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_ExecuteState",
"type": "32int",
"functionCode": 3,
"objectsCount": 2,
"address": 62408,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_ProgNo",
"type": "32int",
"functionCode": 3,
"objectsCount": 4,
"address": 62410,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearXLoad",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62600,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearYLoad",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62602,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearZLoad",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62604,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_SpindleLoad",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62650,
"sendDataOnlyOnChange": "True"
}
],
"attributeUpdates": [
{
"tag": "shared_attribute_write",
"type": "32int",
"functionCode": 6,
"objectsCount": 2,
"address": 29
}
],
"rpc": [
{
"tag": "setValue",
"type": "bits",
"functionCode": 5,
"objectsCount": 1,
"address": 31
},
{
"tag": "getValue",
"type": "bits",
"functionCode": 1,
"objectsCount": 1,
"address": 31
},
{
"tag": "setCPUFanSpeed",
"type": "32int",
"functionCode": 16,
"objectsCount": 2,
"address": 33
},
{
"tag": "getCPULoad",
"type": "32int",
"functionCode": 4,
"objectsCount": 2,
"address": 35
}
]
},
{
"host": "192.168.40.17",
"port": 502,
"type": "tcp",
"method": "socket",
"timeout": 35,
"baudrate": 19200,
"stopbits": 1,
"bytesize": 8,
"parity": "N",
"strict": true,
"repack": false,
"delay_between_requests_ms": 0,
"byteOrder": "BIG",
"wordOrder": "LITTLE",
"retries": true,
"retryOnEmpty": true,
"retryOnInvalid": true,
"pollPeriod": 500,
"unitId": 1,
"deviceName": "\u6c88\u9633\u673a\u5e8aT5-500Q-002",
"connectAttemptTimeMs": 5000,
"connectAttemptCount": 5,
"waitAfterFailedAttemptsMs": 300000,
"attributes": [
{
"tag": "CNC\u578b\u53f7",
"type": "string",
"functionCode": 3,
"objectsCount": 5,
"address": 63001
},
{
"tag": "\u6709\u6548\u8f74\u6570",
"type": "16int",
"functionCode": 3,
"objectsCount": 1,
"address": 63013
},
{
"tag": "\u4e0a\u7535\u6b21\u6570",
"type": "32int",
"functionCode": 3,
"objectsCount": 2,
"address": 63030
},
{
"tag": "\u673a\u5e8a\u7f16\u53f7",
"type": "string",
"functionCode": 3,
"objectsCount": 5,
"address": 63060
},
{
"tag": "\u8f74\u4f3a\u670d\u4fe1\u606f",
"type": "string",
"functionCode": 3,
"objectsCount": 1,
"address": 63100
},
{
"tag": "\u4e3b\u8f74\u4f3a\u670d\u4fe1\u606f",
"type": "string",
"functionCode": 3,
"objectsCount": 1,
"address": 63500
}
],
"timeseries": [
{
"tag": "CNC_AlarmNo",
"type": "16int",
"functionCode": 3,
"objectsCount": 1,
"address": 64503,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_AlarmMsg",
"type": "string",
"functionCode": 3,
"objectsCount": 4,
"address": 64507,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearXSpeed",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62370,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_FeedRate",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62372,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearXPosition",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62200,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearYPosition",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62202,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearZPosition",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62204,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_ToolNo",
"type": "16int",
"functionCode": 3,
"objectsCount": 1,
"address": 62360,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearYSpeed",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62370,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearZSpeed",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62370,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_SpindleRate",
"type": "double",
"functionCode": 3,
"objectsCount": 2,
"address": 62395,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_SpindleSpeed",
"type": "double",
"functionCode": 3,
"objectsCount": 2,
"address": 62385,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_OperateMode",
"type": "32int",
"functionCode": 3,
"objectsCount": 2,
"address": 62406,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_ExecuteState",
"type": "32int",
"functionCode": 3,
"objectsCount": 2,
"address": 62408,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_ProgNo",
"type": "32int",
"functionCode": 3,
"objectsCount": 4,
"address": 62410,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearXLoad",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62600,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearYLoad",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62602,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearZLoad",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62604,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_SpindleLoad",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62650,
"sendDataOnlyOnChange": "True"
}
],
"attributeUpdates": [
{
"tag": "shared_attribute_write",
"type": "32int",
"functionCode": 6,
"objectsCount": 2,
"address": 29
}
],
"rpc": [
{
"tag": "setValue",
"type": "bits",
"functionCode": 5,
"objectsCount": 1,
"address": 31
},
{
"tag": "getValue",
"type": "bits",
"functionCode": 1,
"objectsCount": 1,
"address": 31
},
{
"tag": "setCPUFanSpeed",
"type": "32int",
"functionCode": 16,
"objectsCount": 2,
"address": 33
},
{
"tag": "getCPULoad",
"type": "32int",
"functionCode": 4,
"objectsCount": 2,
"address": 35
}
]
},
{
"host": "192.168.40.18",
"port": 502,
"type": "tcp",
"method": "socket",
"timeout": 35,
"baudrate": 19200,
"stopbits": 1,
"bytesize": 8,
"parity": "N",
"strict": true,
"repack": false,
"delay_between_requests_ms": 0,
"byteOrder": "BIG",
"wordOrder": "LITTLE",
"retries": true,
"retryOnEmpty": true,
"retryOnInvalid": true,
"pollPeriod": 500,
"unitId": 1,
"deviceName": "\u6c88\u9633\u673a\u5e8aT5-500Q-003",
"connectAttemptTimeMs": 5000,
"connectAttemptCount": 5,
"waitAfterFailedAttemptsMs": 300000,
"attributes": [
{
"tag": "CNC\u578b\u53f7",
"type": "string",
"functionCode": 3,
"objectsCount": 5,
"address": 63001
},
{
"tag": "\u6709\u6548\u8f74\u6570",
"type": "16int",
"functionCode": 3,
"objectsCount": 1,
"address": 63013
},
{
"tag": "\u4e0a\u7535\u6b21\u6570",
"type": "32int",
"functionCode": 3,
"objectsCount": 2,
"address": 63030
},
{
"tag": "\u673a\u5e8a\u7f16\u53f7",
"type": "string",
"functionCode": 3,
"objectsCount": 5,
"address": 63060
},
{
"tag": "\u8f74\u4f3a\u670d\u4fe1\u606f",
"type": "string",
"functionCode": 3,
"objectsCount": 1,
"address": 63100
},
{
"tag": "\u4e3b\u8f74\u4f3a\u670d\u4fe1\u606f",
"type": "string",
"functionCode": 3,
"objectsCount": 1,
"address": 63500
}
],
"timeseries": [
{
"tag": "CNC_AlarmNo",
"type": "16int",
"functionCode": 3,
"objectsCount": 1,
"address": 64503,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_AlarmMsg",
"type": "string",
"functionCode": 3,
"objectsCount": 4,
"address": 64507,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearXSpeed",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62370,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_FeedRate",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62372,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearXPosition",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62200,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearYPosition",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62202,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearZPosition",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62204,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_ToolNo",
"type": "16int",
"functionCode": 3,
"objectsCount": 1,
"address": 62360,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearYSpeed",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62370,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearZSpeed",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62370,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_SpindleRate",
"type": "double",
"functionCode": 3,
"objectsCount": 2,
"address": 62395,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_SpindleSpeed",
"type": "double",
"functionCode": 3,
"objectsCount": 2,
"address": 62385,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_OperateMode",
"type": "32int",
"functionCode": 3,
"objectsCount": 2,
"address": 62406,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_ExecuteState",
"type": "32int",
"functionCode": 3,
"objectsCount": 2,
"address": 62408,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_ProgNo",
"type": "32int",
"functionCode": 3,
"objectsCount": 4,
"address": 62410,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearXLoad",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62600,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearYLoad",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62602,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_LinearZLoad",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62604,
"sendDataOnlyOnChange": "True"
},
{
"tag": "CNC_SpindleLoad",
"type": "float",
"functionCode": 3,
"objectsCount": 2,
"address": 62650,
"sendDataOnlyOnChange": "True"
}
],
"attributeUpdates": [
{
"tag": "shared_attribute_write",
"type": "32int",
"functionCode": 6,
"objectsCount": 2,
"address": 29
}
],
"rpc": [
{
"tag": "setValue",
"type": "bits",
"functionCode": 5,
"objectsCount": 1,
"address": 31
},
{
"tag": "getValue",
"type": "bits",
"functionCode": 1,
"objectsCount": 1,
"address": 31
},
{
"tag": "setCPUFanSpeed",
"type": "32int",
"functionCode": 16,
"objectsCount": 2,
"address": 33
},
{
"tag": "getCPULoad",
"type": "32int",
"functionCode": 4,
"objectsCount": 2,
"address": 35
}
]
}
]
},
"id": "661e08fe-5ac2-49f9-b3a4-a150355d9f54"
}

DEBUG logs：
2025-10-15 15:33:45.702 - |ERROR| - [modbus_connector.py] - modbus_connector - __poll_device - 327 - Device 沈阳机床T5-500Q-002 is not connected, cannot connect to server, skipping reading...
2025-10-15 15:33:46.256 - |ERROR| - [modbus_connector.py] - modbus_connector - __poll_device - 327 - Device 沈阳机床T5-500Q-002 is not connected, cannot connect to server, skipping reading...
2025-10-15 15:33:46.727 - |ERROR| - [modbus_connector.py] - modbus_connector - __poll_device - 327 - Device 沈阳机床T5-500Q-002 is not connected, cannot connect to server, skipping reading...
2025-10-15 15:33:47.199 - |ERROR| - [modbus_connector.py] - modbus_connector - __poll_device - 327 - Device 沈阳机床T5-500Q-002 is not connected, cannot connect to server, skipping reading...
2025-10-15 15:33:47.751 - |ERROR| - [modbus_connector.py] - modbus_connector - __poll_device - 327 - Device 沈阳机床T5-500Q-002 is not connected, cannot connect to server, skipping reading...
2025-10-15 15:33:48.219 - |ERROR| - [modbus_connector.py] - modbus_connector - __poll_device - 327 - Device 沈阳机床T5-500Q-002 is not connected, cannot connect to server, skipping reading...
2025-10-15 15:33:48.781 - |ERROR| - [modbus_connector.py] - modbus_connector - __poll_device - 327 - Device 沈阳机床T5-500Q-002 is not connected, cannot connect to server, skipping reading...
2025-10-15 15:33:49.253 - |ERROR| - [modbus_connector.py] - modbus_connector - __poll_device - 327 - Device 沈阳机床T5-500Q-002 is not connected, cannot connect to server, skipping reading...
2025-10-15 15:33:49.726 - |ERROR| - [modbus_connector.py] - modbus_connector - __poll_device - 327 - Device 沈阳机床T5-500Q-002 is not connected, cannot connect to server, skipping reading...
2025-10-15 15:33:50.282 - |ERROR| - [modbus_connector.py] - modbus_connector - __poll_device - 327 - Device 沈阳机床T5-500Q-002 is not connected, cannot connect to server, skipping reading...
2025-10-15 15:33:50.750 - |ERROR| - [modbus_connector.py] - modbus_connector - __poll_device - 327 - Device 沈阳机床T5-500Q-002 is not connected, cannot connect to server, skipping reading...
2025-10-15 15:33:51.226 - |ERROR| - [modbus_connector.py] - modbus_connector - __poll_device - 327 - Device 沈阳机床T5-500Q-002 is not connected, cannot connect to server, skipping reading...
2025-10-15 15:33:51.793 - |ERROR| - [modbus_connector.py] - modbus_connector - __poll_device - 327 - Device 沈阳机床T5-500Q-002 is not connected, cannot connect to server, skipping reading...
2025-10-15 15:33:52.254 - |ERROR| - [modbus_connector.py] - modbus_connector - __poll_device - 327 - Device 沈阳机床T5-500Q-002 is not connected, cannot connect to server, skipping reading...
2025-10-15 15:33:52.738 - |ERROR| - [modbus_connector.py] - modbus_connector - __poll_device - 327 - Device 沈阳机床T5-500Q-002 is not connected, cannot connect to server, skipping reading..