Wika TC12-M Manual do Utilizador descarregar pdf (Página 29)

8. Safety-related instructions for the dierent variants

14083458.01 09/2013 GB/D

WIKA operating instructions models TR12, TC12 (Ex i) 29

The thermometer should be operated with a power-limiting circuit.

max:

2 W

max:

30 V

Powering with Ex ia electrical circuit fullls these conditions. The responsibility rests with the

operator.

Temperature class classication, ambient temperatures

A heating in the connection head can occur with variant 2 through faulty electronics. The

permissible ambient temperatures depend on the housing used and any additionally tted

head-mounted transmitter.

For all WIKA connection heads with built-in WIKA temperature transmitters, the

following interrelation is valid:

The temperature increase on the surface of the connection head or housing is less than

25 K if the following conditions are observed: power supply U

maximum DC 30 V when the

transmitter is operated in a current limit of 22.5 mA.

This yields the following temperature class classication.

Temperature class Ambient temperature

T6 (-50)

-40 … +55 °C

T5 (-50)

-40 … +75 °C

T4, T3, T2, T1 (-50)

-40 … +85 °C

The temperature class is dependent upon the user application and the ambient

temperature.

1) The value in brackets applies only for specic low-temperature designs.

= depending on the built-in transmitter/digital display

The permissible ambient temperatures for third-party products can be seen from the

relevant approvals and/or data sheets. However, an impermissible heat reux from the

process which can exceed the operating temperature of the transmitter or the housing, must

be prevented through suitable heat insulation or a suitably long neck tube.

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Wika TC12-M Manual do Utilizador Página 29