11
Load resistance diagram
KFTF - 20 - I
4... 20 mA
800
700
600
500
400
300
250
50
200
10
15
20
25
30 35 36 40
Load resistance diagram
W
orking r
esis
tanc
e (Ohm)
Operating voltage (V DC)
Admissible
range
800
700
600
500
400
300
250
50
200
10
15
20
25
30 35 36 40
Load resistance diagram
W
orking r
esis
tanc
e (Ohm)
Operating voltage (V DC)
Admissible
range
NOTE
For 4...20 mA devices, DC voltage must be used
(without residual ripple, see permissible range of load
resistance diagram). Do not use pulsating DC voltage.
Connecting diagram
AFTF - 20 -U
Output:
with ⁄ without
0 -10 V
Display
Connecting diagram
KFTF - 20 - I
Output:
with ⁄ without
4...20 mA
Display
NOTE
At transmitters with current output the humidity output (Pin 2)
must categorically be connected !
1 2 3 4
230V AC
24V AC/DC
PLC
PC
+U
B
24
V
AC
/D
C
O
ut
pu
t h
um
id
ity
in
%
r.H
. 0
-1
0V
O
ut
pu
t t
em
pe
ra
tu
re
in
°C
0-
10
V
–UB
-GN
D
1 2 3 4
230V AC
24V DC
+U
B
24
V
D
C
O
ut
pu
t h
um
id
ity
in
%
r.H
. 4
...
20m
A
O
utp
ut
tem
per
at
ur
e
in
°
C
4
...
20m
A
PLC
Working
resistance
–UB GND (optional f
or
LCD back
gr
ound lightling)
Connecting scheme
Parallel operation
Connecting scheme
Individual operation
SUPPLY VOLTAGE:
For operating voltage reverse polarity protection, a one-way rectifier or
reverse polarity protection diode is integrated in this device variant.
This internal one-way rectifier also allows operating 0 - 10 V devices on AC
supply voltage.
The output signal is to be tapped by a measuring instrument. Output volt-
age is measured against zero potential (O V) of the input voltage!
When this device is operated on
DC supply voltage
, the operating voltage
input UB+ is to be used for 15...36 V DC supply and UB – or GND for ground
wire!
When several devices are supplied by one 24 V
AC voltage supply
, it is to
be ensured that all ”positive“ operating voltage input terminals (+) of the
field devices are connected with each other and all ”negative“ operating
voltage input terminals (–) (= reference potential) are connected together
(in-phase connection of field devices). All outputs of field devices must be
referenced to the same potential!
In case of reversed polarity at one field device, a supply voltage short-
circuit would be caused by that device. The consequential short-circuit
current flowing through this field device may cause damage to it.
Therefore, pay attention to correct wiring!
Circuitry
Circuitry
0...10V
0V/GND
0...10V
0V/GND
Power supply
AC 24V~
0V
DC 15-36V = GND
Circuitry
0...10V
0V/GND
V
Power supply
AC 24V~
0V
DC 15-36V = GND
G
HYGRASGARD
®
KFTF - 20
