Hach ANATEL PAT700 - Section 12 Maintenance and Troubleshooting; 12.1 Maintenance; 12.1.1 UV Detect technology

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Modbus Protocol
Error Codes
The following are the error codes used in PAT700 Modbus/TCP protocol.
Exception Code Explanation
0x01 Illegal Function
0x02 Illegal Data address
0x03 Illegal Data value
0x04 Device Failure
0x08 Access Denied