ELECTRICAL CONNECTION INDICATOR M9
4
21
BW25
www.krohne.com
10/2008 • 4000432301 MA BW25 R01 en
HART
TM
communication
When HART
TM
communication is carried out with the ESK, this will not in any way impair analog
measured-data transmission (4...20 mA).
Exception: multidrop operation. In multidrop operation a maximum of 15 devices with HART
TM
function can be operated in parallel, whereby their analog outputs are switched inactive.
(I approx. 4 mA per device).
Power supply
The required supply voltage can be calculated using the formula below:
U
B
= R
tot
.
22 mA + 12 V
where
U
B
= the minimum supply voltage and
R
tot
= the total measuring loop resistance
INFORMATION!
The supply voltage has to be between 12 VDC and 30 VDC. This is based on the total resistance of
the measuring loop. To determine this, add up the resistances of each component in the
measuring loop (not including the flowmeter).
INFORMATION!
The power supply has to be able to supply a minimum of 22 mA.
MA_BW25_R01_en_PRT.book Page 21 Thursday, October 30, 2008 3:49 PM
