Common Errors¶
Quick reference for frequent error messages and solutions.
Modbus Errors¶
"Connection Timeout"¶
Meaning: Device did not respond within timeout period
Solutions: - Verify device IP address - Check network connectivity - Increase timeout setting - Verify device is powered on
"Illegal Function"¶
Meaning: Device doesn't support requested Modbus function
Solutions: - Verify register type (HR/IR/CS/IS) - Check device Modbus implementation - Consult device manual
"Illegal Address"¶
Meaning: Register address doesn't exist on device
Solutions: - Verify register address - Check addressing mode (0-based vs 1-based) - Consult device register map - Check tag configuration
"Illegal Data Value"¶
Meaning: Attempted to write invalid value
Solutions: - Check value range - Verify data type - Check device constraints
"Slave Device Failure"¶
Meaning: Device reported internal error
Solutions: - Check device status/health - Review device error logs - May need device restart
MQTT Errors¶
"Connection Refused"¶
Solutions: - Verify broker IP and port - Check broker is running - Verify firewall rules
"Authentication Failed"¶
Solutions: - Check username/password - Verify user exists on broker - Check user permissions
"Not Authorized"¶
Solutions: - Verify publish permissions - Check ACL rules on broker - Review topic patterns
Configuration Errors¶
"Validation Error"¶
Meaning: Invalid configuration detected
Check: - Required fields filled - Valid data types - No duplicate IDs - Address ranges valid
"Foreign Key Constraint"¶
Meaning: Referenced item doesn't exist
Solutions: - Verify parent items exist - Check for deleted dependencies - Review configuration order