Electric Limitation Of Power; Potential Compensation; Ambient Temperature; Special Conditions (Rise Of Temperature) - ABB SensyTemp MI Instrucciones De Montaje

Electric limitation of power

The following electric values may not be exceeded:
Ui = 30 V
Ii = 101 mA
Pi = according to calculation by means of thermal resistance R
Li = 15 µH per meter
Ci = 280 pF per meter
According to the applied power, the temperature detecting devices show a rise of temperature
Dt in the case of incident. This rise of temperature Dt has to be taken into consideration with
the difference between the temperature of the medium (process temperature) and the temper-
ature category.
The dynamic short circuit current occurring in the case of incident with temperature transmit-
ters in the field of milliseconds does not measurably contribute to a rise of temperature be-
cause of the relatively high thermal inertia of the temperature detecting devices.
Note:
For the use in zone 0, 10 K have to be deducted for the determination of the temperature cat-
egories for T6, T5, T4, T3, 5K and T2, T1. Furthermore, the surface temperatures may not ex-
ceed 80 % of the inflammation temperature. ( DIN EN 50014 and DIN EN 1127-1 )

Potential compensation

The temperature detecting devices have to be integrated into the potential compen-sation of
the place of application. They may be insulated to ground or connected at one spot to the po-
tential compensation system of the intrinsically safe electric circuit of the place of application.
Thermocouples may be connected to ground the case given they are welded in the ground. If
the temperature detecting devices do not meet the voltage test 500V/AC, 1 minute, leakage
current < 5 mA, these temperature detecting devices are marked by voltage test less than 500
V. Here, a connection to ground has to be assumed.

Ambient temperature

In the service area, the ambient temperature may be - 40 °C bis + 80 °C.

2.2 Special conditions (rise of temperature)

Rise of temperature ∆t
The rise of temperature ∆t may calculated as follows:
∆t = R × Pi
th
Example1:
Resistance thermometer diameter 3 mm with protecting well
R = 80 K/W, Pi = 50 mW.
th
With a power Pi = 50 mW, a rise of temperature of 4 K will result in the case of incident.
Example2:
Resistance thermometer diameter 3 mm with protecting well and temperature transmitter
TH02 (Pο = 20 mW according to table below)
R = 80 K/W, P = 20 mW.
th i
The resulting rise of temperature at the test prod will thus amount only to 1,6 K in the case of
incident.
42/10-59 XU
Spannungsprüfung kleiner 500 Vac!
Voltage test lower 500 Vac!
EEx i:
[K/W × W]
∆t = 80 K/W × 0,05 W = 4 K
∆t = 80 K/W × 0,02 W = 1,6 K
SensyTemp MI, IS
or tables 2-1 to 2-5
th
GB 5