Other Devices To Serial Interface; Direct Rs232 Interface Connection (I.e. Pc Com Port) - Honeywell Elster EK280 Applications Manual

EK280

6.4 Other devices to serial interface

6.4.1 Direct RS232 interface connection (i.e. PC COM port)

i
Please follow the application instructions in chapter 6.4.1.2
prevent measurement interference.
6.4.1.1 Connection
EK280
* RTS can be used in place of DTR (DB-9: Pin 7, DE-25: Pin 4). The signal must run continuously at positive
voltage (high-signal) throughout the data transfer. RI is not used!
In EK280 battery operation the signal is switched off again (voltage ≤ 0 V, low signal), in order to preserve
the EK280 battery's life.
6.4.1.2 EK280 jumpers
X6: No jumper
or one jumper on the pins located
near the terminals
Connectible RS232 interface devices often have a direct or capacitative ground potential connection. There
is therefore a risk of interference coupling via ground loops, which may affect pressure and temperature
measurements.
The position of the two jumpers on X5 by the terminals means that the EK280 interface is electrically isolated
from the rest of the circuit and therefore electromagnetic interference coupling is prevented.
The current required by the EK280 interface of around 1 to 2 mA is therefore supplied by the signal
connected to the "Ri" terminal.
Application Manual
TxD
DTR
RxD
DCD
Ri
GND
Uext+
Uext-
X5: No jumpers
or two jumpers on the pins located
near the terminals
("Park-Position")
"EK280 jumpers" to the letter, to
PC, laptop or other
DB-9 DE-25
3 2 TxD
2 3 RxD
4 20 DTR*
GND
5 7
51
RS232