WIKA RTD User Manual

3345267.08 06/2011 GB/D
24 WIKA operating instructions RTD and TC, intrinsically safe designs
GB
For applications requiring instruments of equipment Group II (potentially explosive dust
atmospheres), the following surface temperatures and ambient temperature ranges apply:
Table 2
Marking Power P
i
Ambient
temperature
range (T
a
)
Max. surface temperature
(T
max
) at the sensor or
thermowell tip
II 1D Ex ia IIIC T65 °C Da
II 1/2D Ex ib IIIC T65 °C Da/Db
750 mW (-50)
1)
-40 ... +40 °C
T
M
(temperature of the medium)
+ self-heating
For this, the special conditions
(17) must be observed.
II 1D Ex ia IIIC T95 °C Da
II 1/2D Ex ib IIIC T95 °C Da/Db
650 mW (-50)
1)
-40 ... +70 °C
II 1D Ex ia IIIC T125 °C Da
II 1/2D Ex ib IIIC T125 °C Da/Db
550 mW (-50)
1)
-40 ... +100 °C
1) The values in brackets apply to special designs. These sensors are manufactured using special sealing
compounds. Moreover, they feature housings made of stainless steel and cable glands for low-temperature
ranges.
When there is a built-in transmitter and/or a digital display, the special conditions from the type
examination certicate (see item 17) apply.
Use in methane atmospheres
Owing to the higher minimum ignition energy of methane, the instruments can also be used
where methane causes a potentially explosive atmosphere. The instrument can be optionally
marked with IIC + CH
4
.
For applications that require EPL Gb or Db, instruments with "ia" marking may also be used in
measuring circuits of type "ib".
7.2 Temperature class classication, ambient temperatures
The permissible ambient temperatures depend on the temperature class, the housings used and
any transmitters and/or digital displays tted as options.
When a thermometer is connected to a transmitter and/or a digital display, the lowest value
of either the ambient temperature limits or the highest temperature class will apply. The lower
temperature limit is -40 °C; and -50 °C for special designs.
Where there are neither transmitters nor digital displays mounted within the housing, there will
also be no additional warming.
With a built-in transmitter (optionally with digital display), heating caused by the operation of the
transmitter or digital display may occur.
7. Information on mounting, operation in hazardous areas (Europe)

WIKA RTD Specifications

General

Brand	WIKA
Model	RTD
Category	Measuring Instruments
Language	English