INPUT CARD 2012-IN
Jumpers
The jumpers are set in factory and there is
no need to alter them. The correct positions
are shown in the picture.
Connections
A voltage or a current signal
can be connected in the
input card but not both. A
voltage signal is connected
in terminals 4+ and 3-.
An active (=remotely
powered) current signal is
connected in terminals 2+
and 3-. On 2012-IN card, the current goes
through a 50 ohm resistor and approx 30
ohm self-resetting semiconductor fuse.
The terminals 1+ and 3- provide a 24 VDC
supply for a transmitter. A two-wire
transmitter is connected in terminals 1+ and
2-.
The potentiometer upper end is connected in
terminal 5, feeding 2.5 V excitation. The
lower end is connected in 3. The wiper is
connected in terminal 4.
If using two 2012-IN cards, please note that
they share the common ground (terminals 3
are internally together).
An external switch may be connected in
terminals 6+ and 3-. This card will pull the
terminal 6 voltage to 5 V via
10 kohm. The external contact (NPN or
mechanical) may then pull this voltage to
ground. The switch may be programmed to
activate the hold function, tare the input,
reset the alarms, or to bypass the lowpass
filter.
Operation
The microcontroller sets the multiplexer
"Mux" to measure the V or mA input
according to the configuration settings. The
input is measured using a 24-bit analog-to-
17
6
5
4
3
2
1
ExtSw
+Pot
+V
Com
+mA
+24V
POL
J2
J5
J6
ExtSw
mA
Gnd
V
Pot
+24V
A/D conv
Mux
mA
V/Pot
Pot. excitation 2.5V
5
4
2
Lopass
& Hold
Scaling
+
Tare
-
+
Mea
Dead
Sca
Ch 1
3
