JF-1A Conductivity Sensor
A440-009
Page 44 of 56
FEBRUARY 2009
connection between the two loops then the virtual loop connection is corrupted
and neither loop current will be correctly set by the JF-1A, and, under extreme
circumstances may result in damage to the JF-1A current output devices.
Finally a third connection is made through an RS-232 isolator to allow
connection to the RS-232 data port. The isolator again prevents the data
ground from interfering with the virtual ground needed by the two current loops
operating at the same time.
Note
: the power is not needed to be applied to the power pin on the 4 wire
connector as power for the instrument operation is already provided via the
Conductivity Current Loop.
3
2
1
3
2
1
3
1
2
4
PLC CURRENT DETECTOR
GND
-
+
GND
+24 VDC ISOLATED
POWER SUPPLY
PLC CURRENT DETECTOR
+
-
+
-
GND
+24 VDC ISOLATED
POWER SUPPLY
+
-
GND
RS-232 PORT ISOLATOR
COMPUTER WITH RS-232
DATA INPUT OUTPUT
PORT
RXD
TXD
GND
