4
ELECTRICAL CONNECTIONS
30
H250 M40
www.krohne.com
03/2020 - 4000640706 - MA H250-M40 R06 en
Power supply
The required supply voltage can be calculated using the following formula:
U
ext.
= R
L
* 22 mA + 14 V
with
U
ext.
= minimum supply voltage
R
L
= total measuring loop resistance
HART
HART
HART
HART
®
communication
When HART
®
communication is carried out with the ESK4A, the analogue measured data
transmission (4...20 mA) is not impaired in any way.
Exception for multidrop operation. In multidrop operation a maximum of 15 devices with HART
®
function can be operated in parallel, whereby their current outputs are switched to inactive
(I approx. 4 mA per device).
INFORMATION!
The supply voltage has to be between 14 VDC and 32 VDC. This is based on the total resistance of
the measuring loop. To calculate this, the resistance of each component in the measuring loop
(not including the device) must be added up.
INFORMATION!
The power supply has to be able to supply a minimum of 22 mA.