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Basic principles, overview and ordering information
© 2002 Wieland Electric GmbH Version 2.4* (December 2002)
Part no. 05.591.3389.0
© 2002 Wieland Electric GmbH
93
2.21.5.5
Example for RS485: 2. Sending the character string „RICOS“
Sending the character string "RICOS"
The character string “RICOS” and the character length 5 are transferred.
AB 0 AB 1 AB 2 AB 3 AB 4 AB 5 AB 6 AB 7 Control byte 0
Control byte 1
R I C O S
XX XX XX XX
0
100
.0000
The
“TR”
bit is inverted.
AB 0 AB 1 AB 2 AB 3 AB 4 AB 5 AB 6 AB 7 Control byte 0
Control byte 1
R I C O S XX XX XX XX
0100.000
1
The data is transferred to the transmission buffer. As soon as the
“TA”
bit is
inverted, further data can be sent to the transmission buffer.
EB 0 EB 1 EB 2 EB 3 EB 4 EB 5 EB 6 EB 7 Status byte 0
Status byte 1
XX XX XX XX XX XX XX XX XX
0xxx.xxx
1
The change in the status is relevant for the transmission protocol.
EB 0 EB 1 EB 2 EB 3 EB 4 EB 5 EB 6 EB 7 Status byte 0
Status byte 1
R XX XX XX XX XX XX XX XX
0
000
.xx
11
The transmitted characters are also received in the case of the RS485 interface
and are available in the input area.
By inverting the “RA” bit in control byte 1, the remaining transmitted data from
the receiving buffer is stored in the input area and the receiving buffer is emptied
again.
EB 0 EB 1 EB 2 EB 3 EB 4 EB 5 EB 6 EB 7 Status byte 0
Status byte 1
I C O S XX XX XX XX XX
0
011
.xx
0
X
The remaining 4 characters from the “RICOS” character string are available in the
input area and can be read out by the application.
2.21.5.6
Example for RS 485: 3. Receiving the character string “Wieland”
Receiving the character string “Wieland”
As soon as RA
≠
RR, the first characters in the input bytes are available.
AB 0 AB 1 AB 2 AB 3 AB 4 AB 5 AB 6 AB 7 Control byte 0
Control byte 1
XX XX XX XX XX XX XX XX XX
0xxx.00
0
x
This status byte indicate the receipt of at least one byte. Once the received
character or characters have been processed, the “RA” bit in the control byte
must be inverted. If further data is available in the transmission buffer, it is stored
in the input byte area.
EB 0 EB 1 EB 2 EB 3 EB 4 EB 5 EB 6 EB 7 Status byte 0
Status byte 1
W
XX XX XX XX XX XX XX XX
0
000
.0x
1
x
A “W” byte has been received;
If the data has been read by the application, “RA” is inverted and further receiving
data is stored in the input area.
AB 0 AB 1 AB 2 AB 3 AB 4 AB 5 AB 6 AB 7 Control byte 0
Control byte 1
XX XX XX XX XX XX XX XX XX
0xxx.00
1
x
The receipt of further characters is displayed by different values for RA and RR.
EB 0 EB 1 EB 2 EB 3 EB 4 EB 5 EB 6 EB 7 Status byte 0
Status byte 1
i e l a n d
XX XX XX
0
110
.0x
0
x
Six further bytes are available for retrieval by the application.
