S+S Regeltechnik HYGRASGARD RFF Series Operating Instructions, Mounting & Installation page 15

G
®
HYGRASGARD
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
voltage is measured her 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!
RFF ⁄ RFTF
Connecting scheme
Power supply
AC 24V~ 0V
DC 15-36V = GND
Connecting scheme
Power supply
AC 24V~ 0V
DC 15-36V = GND
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.
Load resistance diagram
800
700
600
500
400
300
250
200
50
10
Operating voltage (V DC)
15
Individual operation
Circuitry
V
Parallel operation
Circuitry Circuitry
Load resistance diagram
Admissible
range
15 20 25 30 35 36 40
4 ... 20 mA