Metrohm 768 KF Oven - Manual (Page 34)

3.3 Characteristics of the RS232 interface
768 KF Oven
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3.3 Characteristics of the RS232 interface
3.3.1 Data transfer protocol
The KF Oven is configured as DTE (Data Terminal Equipment).
The RS232 interface has the following technical specifications:
Data interface in accordance with the RS232C standard, with selectable parameters.
Max. line length:
80 characters + CR + LF
Control characters: CR (ASCII DEC 13)
LF (ASCII DEC 10)
XON (ASCII DEC 17)
XOFF (ASCII DEC 19)
Cable length: max. ca. 15 m
Start 7 or 8 data bits Parit.bit 1 or 2 stop bit(s)
For interconnections of the 768 KF Oven with non-Metrohm units, only a shielded data cable
(e.g. METROHM D.104.0201) may be used. The cable shielding must be faultlessly earthed
at both units (pay attention to current loops; always use star-head earthing). Only connectors
with adequate shielding may be used (e.g. METROHM K.210.0001 with K.210.9004).
3.3.2 Handshake
3.3.2.1 Software handshake, SWChar
Handshake inputs at the Oven (CTS, DSR, DCD) are not checked.
Handshake outputs (DTR, RTS) are set by the Oven.
As soon as a LF is recognized, the Oven sends XOFF. It can then receive 6 extra characters
and store them.
However, the Oven also sends XOFF, if its input buffer contains 60 characters. After this, it
can receive maximum 22 extra characters (incl. LF).
If the transmission is interrupted for the time of 4 characters after the Oven has sent XOFF,
the string received earlier is processed even if no LF has been sent.
Oven as receiver:
60 characters
TxD
RxD Data output
Data input
Time of 4 characters
max. 22
XOFF XON
String is
LF
400
XOFF
characters
KF Oven External device
processed
Time
us