KROHNE DA Flap-type EN - Manual (Page 14)

8.2 Electrical signal output ESK
8.2.1 Electrical connection
The connecting terminals of the M9 display have a pluggable design and can be removed in order to
connect the lines.
8.2.2 HART
TM
communication with the ESK
HART TM communication is not compellingly required in order to operate the ESK.
When HART TM communication is carried out with the ESK, this does not by any means impair analog
measured value transfer (4...20mA)
Exception at Multidrop operation. In Multidrop operation a maximum of 15 instruments with HART TM
function can be operated in parallel, whereby their current outputs are switched inactive (approx. 4 mA).
If a HART TM communicator (type Fisher Rosemount, Model 275) or a PC with HART TM modem PC is used,
the resistor which is connected in series (R
ext.
) has to exceed 250 Ohms.
In this type of operation the auxiliary power must amount to at least 18 V. The communicator or the PC is
connected as shown in the drawing above.
It can be operated optionally via the connecting terminals of the ESK (2) or via an external resistance (1)
connected in series. The counter cannot be read out or operated by means of HART TM communication!