Euphonix 740.0065NA - Handbuch (Seite 10)

PHÖNIX Messtechnik GmbH, Salzschlirferstr. 13, D-60386 Frankfurt/M., Germany, Tel: +49/69/416742 -20, Fax: -29
9
1 General
The PHÖNIX type 740.0060/65 level switches can be used on all PHÖNIX magnetically-operated level
gauges. The switching behaviour is bistable. Should the electrical supply fail and return, the position of the
impulse magnet will be "memorised". The direction of the switching can be changed by reversing the
printed circuit board (see chapter 2.2).
The level switch hysteresis depends on the liquid level gauge (s. chapter 9) and can be used as a two-
step action.
Because of its low mass switching element this level switch is particularly suitable in installations with
strong vibrations,
1.1 Type 740.0060
Two types of operation are available with the PHÖNIX type 740.0060 level switch.
a) Used as electronic power switch, it is recommendable for the switching of heavy AC-loads, as the
switching occurs contactless (TRIAC). Protective measures for the REED-switch are not necessary, as
it is only used for the control circuit of the TRIAC,
b) Used as a Reed miniswitch, it is usable for the switching of 0/4-20 mA current loops, NAMUR-signals,
logic levels, small AC/DC-voltages etc.
ATTENTION: TRIAC and REED cannot be used at the same time!
Fig.1 Circuit design 740.0060
1.2 Type 740.0065/65NA
The level switch type 740.0065 (fig. 2a) is reduced to a Reed miniswitch for low level AC/DC loads. The
type 740.0065NA is alternative - as shown in fig. 2b - fitted with two resistors (R
S
=1k, R
P
=10k) for usage
in NAMUR circuits.
Fig. 2a: Circuit 740.0065 Fig. 2b: Circuit 740.0065NA