6 DATA COMMUNICATION USING THE NON PROCEDURE PROTOCOL MELSEC-Q

(2)Confirmation using the module and GX Configurator-SC

1)Confirmation using the display LED

When the Q series C24 detects an error, including a transmission error, the ERR LED lights up. (See Chapter 10.)

2)Confirmation using GX Configurator-SC

•The monitor function is used to check for errors. (See Sections 8.6.3 and 8.6.5.)

•The ERR LED is turned off with the ERR LED OFF function. (See Section 8.6.10.)

3)Confirming the error code

Use one of the following to confirm the error code.

•GX Configurator-SC monitor function (See Section 8.6.5.)

•GX Developer buffer memory monitor function (monitors addresses

258H/268H)

(3)Receive data when a reception error occurs

(a)Storing receive data

The receive data for which an error was detected is discarded and only the normally received data is stored in the Q series C24.

Thus, there may be missing data among the data that has been read to the PLC CPU when a reception error occurs.

(b)Reading receive data

When receive data is read to the PLC CPU by turning the reception abnormal detection signal (X4/XB) ON, the data that was normally received prior to the error detection is read. Read and discard receive data as needed.

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