24
TGH1266E -
05/04
Serial Interface
Interface Protocol
Operation and Settings
The standard RS232 interface makes it possible to connect non- system devices. These may be
computer systems, SPC control units, or similar items. With knowledge of the interface protocol
being used, it is possible for the user to write his own programs and use them. The protocol for
data transmission corresponds to the format for BENDER measuring device interfaces.
Data transmission generally makes use of ASCII characters. The interface data are:
Baud rate:
9600 bauds
Transmission:
1 start bit, 7 data bits, 1 parity bit, 1 stop bit (1,7,E,1)
Parity:
even (P=0)
Checksum:
sum of all transmitted bytes = 0 (without CR and LF)
Address:
001 ... 255 and 000 (=general address)
Protocols:
Master
:;XXX:ABCDE 12345&XYZ<CR><LF>
Slave
::XXX:ABCDE 12345&XYZ<CR><LF>
:;
recognition of start of master transmission
::
recognition of start of slave transmission
XXX
address
:
start byte for command
ABCDE
command, consisting of a maximum of 5 ASCII characters
(blank character)
start byte for data
12345
data, consisting of a maximum of 5 ASCII characters,
maximum size: 65 535
&
start byte for checksum
XYZ
checksum, consisting of a maximum of 3 ASCII characters
<CR><LF>
end of transmission (carriage return, line feed)
The command and the data may be smaller than 5 bytes, or may even be omitted altogether. In
every case, the end is recognised from the start byte of the next character type.
