KROHNE H250 M8-M9-M10 EN - Manual (Page 23)

ELECTRICAL CONNECTIONS
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H250
www.krohne.com 04/2011 - 4000269302 MA H250-R02 en
HART ® communication
When HART ® communication is carried out with the M8E display, the analogue measured data
transmission (4...20 mA) is not impaired in any way.
Exception for multidrop mode. In multidrop mode, a maximum of 15 devices with HART ® function
can be operated in parallel, whereby their current outputs are switched inactive
(I approx. 4 mA per device).
Load for HART ® communication
The maximum load resistance is calculated as follows:
Configuration
The M8E electronic indicator can be configured via HART ® communication. DD (Device
Descriptions) for AMS 6.x and PDM 5.2 as well as a DTM (Device Type Manager) are available for
configuration. They can be downloaded free of charge from our website.
The current flow rate can be transmitted using the integrated HART ® communication. A flow
counter can be configured. Two limit values can be set and monitored. The limit values are
assigned either to flow values or to the counter overflow. The limit values are not depicted on the
display.
INFORMATION!
For HART
® communication a load of at least 230 ohm is required.
DANGER!
Use a twisted two-core cable to prevent electrical interference from impeding the DC output
signal.
In some cases a shielded cable may be necessary. The cable shield may only be earthed
(grounded) at one place (on the power supply unit).
MA_H250_R02_en_269302_PRT.book Page 23 Tuesday, April 12, 2011 10:17 AM