242 • I/O modules
RS232C interface 750-650
Modular I/O System
ETHERNET TCP/IP
Initialization of the module:
•
set IR bit in the control byte to "1"
•
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 bytes 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: data in input bytes 0 to 2 characters are available
•
amount of characters is specified in IL0 to IL2
•
characters in 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 initia-
lization request has priority and will stop transmitting and receiving of data
immediately.
Attention
Resetting the initialization bit can be performed with the following message.
Message: input buffer full (Bit 3)
Input buffer is full. Data which is being currently received is now lost.
Содержание I/O-SYSTEM 750
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