G
4 DTR. LI-24
(ENG
)
5.3. Permitted intrinsic-safety parameters
5.3.1.Permitted sensors supply parameters (to 1, 2, 3, 4, 5 terminal sensors connection)
Uo = 6V, Io = 0.1A, Co = 10
μF, Lo = 1.5mH, Po = 0.5W
5.3.2. Permitted input parameters (to <DC>, <DC> terminals current loop)
The transmitters should be powered from power suppliers with the relevant intrinsic safety certificates,
witch output parameters to danger zone not exceed the acceptable supply parameters to the transmitters
as bellow:
a) Power supply with linear characteristics
Ui = 30V, Ii = 0.1A, Pi = 0.75W, Li = 1.1mH, Ci = 5nF
Ta ≤ 70
0
C and T5
b) Power supply with the trapezoidal characteristics
Ui = 24V, Pi = 0.7W, Ii = 0.05A, Li = 1.1mH, Ci = 5nF
Ta ≤ 75
0
C and T5
c) Power supply with the rectangular characteristics
Ui = 24V, Pi = 0.6W, Ii = 0.025A, Li = 1.1mH, Ci = 5nF
Ta ≤ 75
0
C and T5
Ui = 24V, Pi = 1.2W, Ii = 0.05A, Li = 1.1mH, Ci = 5nF
Ta ≤ 75
0
C and T4
5.4. Supply examples
Used bellow signs Uo and Io accord to transmitter supply and are other than above mentioned
(p. 5.3.1)
5.4.1. - Power supply with linear characteristics
Power supply with a “linear” characteristic may be a typical barrier with parameters:
Uo = 30V Io = 0.1A Rw = 300
Zasada zasilania o charakterystyce liniowej (Radwanice)
Rw
Uo
I
D
Ii
Io
Fig.2. The supplying principle with a source of linear characteristics
5.4.2.
– Power supply with the trapezoidal characteristics
Uo = 24V Io = 0.05A Po = 0.6W U
Q
= 48V
for Ta
75
C and T5
Io
Ui
Uo
D
I
Rw
U
Q
Ii
Fig.3. The supplying principle with a source of trapezoidal characteristics.
If Uo < parameters U
Q
, Ii, Pi are interrelated as follows:
U
Q
=
Rw =
U
Q
2
4Po
Io
Uo • (U
Q
– Uo)
R
Po =
4Po
Io²
Q
Io
I
Uo
U
U
Uo
I
Io
Q
i