The PLC is able to control transmission and reception of data by means of the control byte and the status byte.
Initialization of the module:
∙set IR in the control byte
∙transmit/receive functions are blocked
∙output/input buffers are erased
∙serial interface module will load its configuration data
Transmitting data:
∙TR≠TA: put characters into output byte 0 to 2
∙amount of characters is specified in OL0 to OL2
∙TR is inverted and read out
∙characters are put into output buffer if TR=TA
Receiving data:
∙RR≠RA: in input byte 0 to 2 characters are available
∙amount of characters is specified in IL0 to IL2
∙charactersin IL0 to IL2 are read out
∙RA is inverted and read out
∙all characters are read when RR=RA
The transmitting and receiving of data can be done simultaneously. The initialization request has prioirity and will stop transmitting and receiving of data immediately.
Message: input buffer full (Bit 3)
Input buffer is full. Data which are received now are lost.
RS232,TTY,RS485 |
| 7 |
