Datatransfer - WAGO 750-651 Manual

18 • 750-651 (/xxx-xxx) [TTY-Interface 20mA Current Loop]

Datatransfer

TA
RR
IA
BUF_F
IL 0,
IL 1,
IL 2
0
2.1.1.9 Datatransfer
With the control and status byte the controlling of the sending and receive
mode takes place. Requests are indicated by a bit change of state. An assigned
bit indicates execution by adopting the value of the request bit.
Initialization of the module:
 Set IR bit in the control byte
 Initialization of the module
 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
 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 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
Bit 7 Bit 6 Bit 5
0 IL 2 IL 1
Transmit acknowledge
Receive request
Initialization acknowledge
Buffer full
Input length (number of received characters , which have been stored in the
input data)
Constant value must always be 0.
Status byte
Bit 4 Bit 3 Bit 2
IL 0 BUF_F IA
Bit 1 Bit 0
RR TA
WAGO-I/O-SYSTEM 750
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