INFICON T-Guard Leak Detection Sensor Interface description - Manual (Page 4)

4
General
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1.2 RS232 Interface Connecting Cable
The RS232 interface is wired as data communication equipment (DCE).
T-Guard™ Leak Detection Sensor provides a 9-way sub-D socket for the connector.
The signals are assigned as follows:
The other pins are not being used.
The levels on the RS232 interface are defined as follows:
Physical Assignment
You can use a standard RS232 cable (straight-through connecting cable, RxD and
TxD not crossed, no Null Modem Cable). The RS232 hardware handshake must be
switched off in your software program. If you cannot switch off the hardware
handshake, an RS232 cable wired as follows may be used:
Pin Name Signal
2 RxD Receive data (T-Guard™
→ PC)
3 TxD Transmit data (PC
→ T-Guard™)
5 GND Reference Ground
Level Low (L) High (H)
Voltage Range -3 V … -25 V 3 V … 25 V
Logic State logical 1 logical 0
Level Designation Mark Space
Fig. 1-1 Physical assignment of the RS232 cable to work around
hardware handshake.