Metrohm 774 Oven Sample Processor - Manual (Página 138)

5 Descripción detallada
5.12.3 Pin Assignment
RS232C Interface
Transmitted Data (TxD).
If no data are transmitted, the line is held in the “ON” condi-
tion. Data will only be sent when CTS and DSR are in the
”ON” condition and DCD is in the “OFF” condition.
Received Data (RxD)
Data will only be received when DCD is “ON”.
Request to Send (RTS)
ON condition: the changer is ready to send data.
Clear to Send (CTS)
ON condition: Remote station is ready to receive data.
Data Set Ready (DSR)
ON condition: The transmission line is connected.
Signal ground (GND)
Data Carrier Detect (DCD)
ON condition: The level of the received signal is within the
tolerance range (remote station is ready to send data).
Data Terminal Ready (DTR)
ON condition: Instrument is ready to receive data.
Pin 2
Transmitted Data
Pin 3
Received Data
Pin 4
Request to Send
Pin 5
Clear to Send
Pin 6
Data Set Ready
Pin 7
Signal Ground
Pin 8
Data Carrier Detect
Pin 20
Data Terminal Ready
Protective earthing
Direct connection from cable plug to the protective ground of the instrument.
Polarity allocation of the signals
-
Data lines (TxD, RxD)
voltage negative (<–3 V): signal state "ON"
voltage positive (>+3 V): signal state "ZERO"
- control or message lines (CTS, DSR, DCD, RTS, DTR)
voltage negative (<–3 V): OFF state
voltage positive (>+3 V): ON state
In the transitional range from +3 V to –3 V the signal state is undefined.
Driver 14C88
according to EIA RS232C specification
Receiver 14C89 " "
774 Oven Sample Processor, Instrucciones para el uso 132