EN
14073045.04 03/2019 EN/DE
WIKA operating instructions model TR25 (Ex i)
24
9. Electrical connection values
9.1 Electrical data without built-in transmitter or digital display
For group II instruments (potentially explosive gas atmospheres)
3)
, the following maximum
connection values apply:
U
i
= DC 30 V
I
i
= 550 mA
P
i
(at the sensor
1)
) = 1.5 W
For Group II instruments (potentially explosive dust atmospheres), the following maximum
connection values apply:
U
i
= DC 30 V
I
i
= 550 mA
P
i
(at the sensor
2)
) = for the values, see „Table 2“ (column 2), chapter 7.1.2 “Ex marking”
The internal inductance (L
i
) and capacitance (C
i
) of the TR25 are negligible.
Sensor circuit in Ex ia or ib, IIC intrinsic safety ignition protection
Only for connection to intrinsically safe circuits with the following maximum output values
for Group II instruments (potentially explosive gas atmospheres):
U
o
= DC 30 V
I
o
= 550 mA
P
o
= 1.5 W
For Group II instruments (potentially explosive dust atmospheres), the following maximum
output values apply to their connection to intrinsically safe circuits:
U
o
= DC 30 V
I
o
= 550 mA
P
o
= for the values, see „Table 2“ (column 2), chapter 7.1.2 “Ex marking”
1) The permissible power to the sensor depends on the temperature of the medium TM, the temperature
class and the thermal resistance Rth, but shall not be more than 1.5 W.
For calculation examples, see chapter 10 “Calculation examples for self-heating of the tubular body at the
sensor installation point”.
2) The permissible power to the sensor depends on the temperature of the medium T
M
, the maximum
allowed surface temperature and the thermal resistance R
th
, but shall not be more than the values from
„Table 2“ (column 2), see chapter 7.1.2 “Ex marking”.
3)
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
.
9. Electrical connection values
