Aplisens APR-2000ALW - Page 14

E6 12 DTR.APC.APR.ALW.03(ENG)
Appendix Exi.ATEX
If Uo < then parameters Uq, Io, Po are interrelated as follows:
Uq = , Rw = , Po = for Uo ≤ 1/2U
Q
5.4. For power supply with a rectangular output characteristic
Ui = 24V Ii = 25mA Pi = 0,6W -40ºC  Ta  80ºC and T5
Ui = 24V Ii = 50mA Pi = 1,2W -40ºC  Ta  80ºC and T4
The supply of power from a source with a rectangular characteristic means that the voltage of the Ex power
supply remains constant until current limitation activates.
The protection level of power supplies with a rectangular characteristic is normally “ib”.
The transmitter powered from such a supply is also an Ex device with protection level “ib”.
Example of practical provision of power supply.
– use a stabilized power supply with Uo=24V with protection level „ib” and current limited to Io=25mA.
5.5. Input inductance and capacity
Ci=2.5nF, Li=18µH
Ci=30nF, Li=0,75mH - for MID version
5.6. Supply voltage min.: 10.5VDC**)
5.7. Load resistance:
- from 28V linear supply
Ro max [Ω] =
- from a source with trapezial or rectangular characteristic supply
Ro max [Ω] =
*) barrier resistance;
**) for MID version pressure transmitters - 13.5V DC without backlight or 16.5V DC with backlight.
U
Q
Io
Usup. – 10.5V **
0.0225A
28V – 10.5V** – (300Ω* x
·
0.0225A)
0.0225A
U
Q
2
4Po
Io
Uo(U
Q
– Uo)
Rw