Euphonix Maintenance, Warranty, Using the type 740.0065NA in a hazardous area

Fig. 8: A two-step action with a PHÖNIX level switch type 740.0060 utilising its hysteresis.

4.2 Using the type 740.0065NA in a hazardous area

The limit switch type 740.0065NA is designed for usage in NAMUR-circuits (s. fig. 2b). It consists only of passive devices (switch and resistors), which allows - according to EN 50020 / VDE 0170 part 7 - the us- age in hazardous areas zone 1 and 2, if they are part of a intrinsic save circuit and the maximum values of voltage, current and power are not exceeded. The maximum of self heating is determined by RS (RT= 180°C/W) and the utilised power supply. If using the type 740.1061 (Pmax=51mW), the heating up is less than 10°C.

Typ 740.0065N

Typ 740.0065N

hazardous area

safe	supply
area

Fig. 9: Usage of the type 740.0065NA in a hazardous area

4.3 Heat protection in high temperature

If medium temperature is more than 150°C (>260 °C for 740.0065NA) to reduce the heat radiation a heat protection plate (Order-No.: 5745000159) has to be mounted between the tube and the switch. In this case the switch must not be isolated together with the tube.

5 Maintenance

The switch is free of maintenance.

6 Warranty

We grant a guarantee period of 24 months for our products, provided that they have been handled and operated under conditions described in the Operating Manual. In case of wear and spare parts we only guarantee for failures in construction and material.

PHÖNIX Messtechnik GmbH, Salzschlirferstr. 13, D-60386 Frankfurt/M., Germany, Tel: +49/69/416742 -20, Fax: -29

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