2
DEVICE DESCRIPTION
8
GA24
www.krohne.com
04/2015 - 4000836702 - MA G24-Ex-II2G-AD R03 en
2.7 Ambient temperature / temperature classes
Because of the influence of the temperature of the product, no fixed temperature class is
assigned to variable area flowmeters with attached electrical equipment. In fact, the
temperature class of a device is a function of the temperature of both the product and the
environment. There is no distinction between devices with one or two contacts. The assignment
is outlined in the following tables.
The tables take into account the following parameters to determine the permissible
temperature class:
•
Ambient temperature T
amb.
•
Product temperature T
m
•
attached equipment
•
Supply type (maximum values for P
i
)
Maximum permitted product temperature T
m
for limit switch TG21
The maximum permitted ambient and product temperature for the type MS14 limit switch is
85
°
C / 185
°
F for temperature classes T6 ... T1.
The minimum permitted ambient temperature T
amb
for all versions is -20
°
C / -4
°
F.
2.8 Electrical data
The connection of limit switches MS14/. or TG21 may only be connected to intrinsically safe
circuits
to DIN 19234 with the following max. values:
MS14/.
TG21
Supply
Type 1
Type 2
Type 3
Temperature
class
T6
T5
T4...T1 T6
T5
T4...T1 T6
T5
T4...T1
T
m
in
°
C
1
70
85
95
60
75
95
35
50
70
T
m
in
°
F
1
158
185
203
140
167
203
95
122
158
1
These values may be limited by the Installation and Operating instructions. Observe the maximum values listed in the
Installation and Operating instructions.
Pi
Ui
Ii
Ci
Li
1 W
30 VDC
100mA
≈
0 nF
≈
0
µ
H
Supply
Pi
Ui
Ii
Ci
Li
Type 1
34 mW
16 VDC
25mA
165 nF
150
µ
H
Type 2
64 mW
16 VDC
25mA
165 nF
150
µ
H
Type 3
169 mW
16 VDC
52mA
165 nF
150
µ
H
