The register number to be read is inconsistent with the PLC register number actually read

[yangyu-cn-cn]

I use Panasonic PLC. When reading the value of a holding register with demo program, it is inconsistent with the actual value. For example, I read the value of register number 3002 and actually returned the value of register number 3001.、

Change the statement at the ‘problem‘ tag to ‘RegNumber := ARegNumber;‘ Post problem solving：

function TIdModBusClient.SendCommand(const AModBusFunction: TModBusFunction; const ARegNumber: Word; const ABlockLength: Word; var Data: array of Word): Boolean; var SendBuffer: TModBusRequestBuffer; ReceiveBuffer: TModBusResponseBuffer; BlockLength: Word; RegNumber: Word; dtTimeOut: TDateTime; {$IFDEF DMB_INDY10} Buffer: TIdBytes; RecBuffer: TIdBytes; iSize: Integer; {$ENDIF} begin {$IFDEF DMB_INDY10} CheckForGracefulDisconnect(True); {$ELSE} CheckForDisconnect(True, True); {$ENDIF} SendBuffer.Header.TransactionID := GetNewTransactionID; SendBuffer.Header.ProtocolID := MB_PROTOCOL; { Initialise data related variables } RegNumber := ARegNumber - FBaseRegister; //--------problem--------// { Perform function code specific operations }

[JensMertelmeyer]

This is not a problem, this is as designed.

You can adjust the BaseRegister property and set it to 0. The default value is 1.

[yangyu-cn-cn]

Thank you for your answer. I was negligent.