Metrohm 756 KF Coulometer - Manual (Page 105)

4.3 Properties of the RS 232 Interface
756/831 KF Coulometer, Instructions of Use 97
4.3 Properties of the RS 232 Interface
Data Transfer Protocol
The Coulometer is configured as DTE (Data Terminal Equipment).
The RS 232 interface has the following technical specifications:
• Data interface according to the RS 232C standard, adjustable transfer parame-
ters, see page 21.
• Max. line length: 512 characters
• Control characters: C
R
(ASCII DEC 13)
L
F
(ASCII DEC 10)
XON (ASCII DEC 17)
XOFF (ASCII DEC 19)
• Cable length: max. approx. 15 m
Start 7 or 8 Data Bit Parity Bit 1 or 2 Stop Bit
Only a shielded data cable (for example, METROHM D.104.0201) may be used to
couple the Coulometer with foreign devices. The cable shield must be properly
grounded on both instruments (pay attention to current loops; always ground in a
star-head formation). Only plugs with sufficient shielding may be used (for example,
METROHM K.210.0381 with K.210.9045).
4.3.1 Handshake
Software-Handshake, SWchar
Handshake inputs on the Coulometer (CTS) are not checked.
Handshake outputs (DTR, RTS) are set by the Coulometer.
The Coulometer sends XOFF when its input buffer contains 384 characters. After this
it can receive 128 extra characters (including L
F
).
Coulometer as Receiver :
Coulometer external device
Data output
Data input
max. 128
characters
384 characters
XOFF XON
L
F
RxD
TxD
Time