Quatech INTERBUS S Network Card User Manual


 
RS232,TTY,RS485 750-650,651,653
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6
Structure of input and output data:
The module is a combined analog input and output module with 2 x 16 bit input and
output data. The transfer of the data to be transmitted and the received data is made via
up to 3 output and 3 input bytes. One control byte and one status byte are used to control
the floating data.
Requests are indicated by a change of a bit. An assigned bit indicates execution by
adopting the value of the request bit.
Up to 3 characters which have been received via interface can be stored in the input
bytes 0 to 2. The output bytes will contain the characters to be sent.
The control byte consists of the following bits:
Control Byte
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0 OL2 OL1 OL0 0 IR RA TR
Con-
stant
value
must
always
be 0.
Frames available in output
area, OL2 is always 0.
eg. OL2, OL1, OL0 = 0,1,1
3 characters should be sent
and put into the output.
Constant
value must
always be 0.
Initialization
request
Reception
acknow-
ledgement
Trans-
mission
request
The status byte consists of the following bits:
Status Byte
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0 IL2 IL1 IL0 BUF_F IA RR TA
Con-
stant
value
must
always
be 0.
Frames available in input
area, IL2 is always 0. eg.
IL2,IL1,IL0 = 0,1,0
2 characters were received
and reside in input 0 and input
1.
Input buffer
is full.
Initialization
acknow-
ledgement
Reception
request
Trans-
mission
acknow-
ledgement