12
9.3
Electrical installation
For the connection of the operating voltage and the external signal lines the back panel of the
device has to be removed and the four M12 screw joints, placed at the sidewall of the device,
have to be used. The cable ends must be equipped with wire end ferrules with a maximum cross
section of 0.5 mm
²
and placed in the device according to the following descriptions.
9.3.1
Connection of power supply
The supply voltage of 24 Volt DC will is to connect at the terminals 31/32. An electrical in-
stalled load of 5 Watt is necessary. The terminal 31 has the positive and the terminal 32 the
negative potential. An operation with 230 Volt AC is allowed only with the power supply unit
provided by the manufacturer.
Note:
For applications in industrial surroundings with high electrical leakages current it is recom-
mended to connect the device to an additional protective grounding.
9.3.2
Output water hardness by active current loop
The signal is a coded residual hardness signal and the current of 4 … 20 mA represents a re-
sidual water hardness in the range of 0 … 2% or 0 … 10%. The current loop 4 ... 20 mA is
connected to the terminals 17/18. The terminal 17 represents the positive and terminal 18 the
negative potential.
The following external requirements for electrical connections have to be complied.
External requirements:
do not connect external voltage
use passive loop resistance of maximum 250 OHMS
9.3.3
Connection ON / OFF signal
Softening Control is staying in ON-mode as long as there is no short circuit between the ter-
minals 20/21. It will stay on OFF-mode while both terminals are connected. In this state no
measurement will be done. With termination of the OFF-Line mode and before starting of the
normal measurement operation, the sensor stays in soft water for 1 minute.
The OFF-Line mode should be used for some minutes or hours only, for avoid-
ing a non-monitoring of the softening plant as well to protect the sensor system
against germs.
ON-Line-Mode
20 21
OFF-Line-Mode
20 21