Chapter 6 Applied Instructions The PLC sets the flag to ON when the reading success flag indicates that receiving data is complete and the data checked are correct. If an error occurs in receiving data or a communication timeout occurs, the error flag is set to ON refer to the error codes). The PLC does not reset any of the reading success or error flags to OFF in the data exchange since the reading success flag and error flag of every connection number are not ON simultaneously. 8. The following table describes the SR (only-read registers) in the data exchange function. 9. The data exchange function does not provide a writing success flag.
It is suggested that you refer to the connection number in the execution to judge whether the writing of data succeeds or not. For example, when the executed connection number is 3 in SR1336, the successive communication actions are to read the communication data first, and then to write the communication data after reading is completed. The connection number is incremented to 4 after writing is completed. 6_ 10. If the reading data length value in S 6 and the initial device in S 7 are out of the range of the D or M device, the length value in S 6 is automatically set to be in the valid range.
For example, if the length value in S 6 is100 and the initial device of S 7 is M8182, the value in S 6 is set to 10 automatically. 11. In the following cases, the instruction is not executed and the parameter settings in HWCONFIG are not changed for the communication port, and SM0 is set to ON, and the error code in SR0 is 16#200B. An input error occurs when the setting values in S 1 , S 2 , S 4 and S 8 are out of the specified range. When S 4 or S 8 function code selects the bit type for reading or writing data, the local device for storing data S 7 or S 11 must select the M device. An input error occurs if the selection is not M.
When the S 4 or S 8 function code selects the word type for reading or writing data, the local device for storing data S 7 or S 11 must select the D device. An input error occurs if the selection is not D. 6-583 SR No. Description SR1335 Cycle of the actual connections 1–32 in the COM1 data exchange SR1336 Cyclic connection number in the current COM1 data exchange SR1340–SR1371 Error codes of the connections 1–32 in the COM1 data exchange SR1375 Cycle of the actual connections 1–32 in the COM2 data exchange SR1376 Cyclic connection number in the current COM2 data exchange SR1380–SR1411 Error codes for connections 1–32 in the COM2 data exchange