Writing to send buffer

The instructions SendCharacters and SendCharactersAndClearString automatically generate the data in the send buffer.

Send buffer layout

1.  (1) Storage area for the number of bytes to be sent
2.  (2) Storage area for the data to be sent

Bold numbers indicate the order of transmission. The storage area for the data to be sent starts with the second word of the send buffer (offset 1). Offset 0 contains the number of bytes to be sent and this register is internally handled by the PLC (users should use it read only). The maximum volume of data that can be sent is 2048 bytes.

If F159_MTRN is used for transmission, the data must be copied to the send buffer using a transfer instruction, e.g. F10_BKMV.