KROHNE H250 M8-M9-M10 EN - Manual (Page 29)

ELECTRICAL CONNECTIONS
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H250
www.krohne.com 04/2011 - 4000269302 MA H250-R02 en
Load for HART ® communication
The maximum load resistance is calculated as follows:
Configuration
The ESK 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 monitored. The limit values are assigned
either to flow values or to the counter overflow.
Self monitoring - Diagnostics
During both start-up and operation, a wide variety of diagnostic functions are performed
cyclically in the ESK2A, in order to guarantee function reliability. When an error is detected, a
failure signal (high) is activated (current > 21 mA) via the analogue output. In addition, more
detailed information can be requested via HART
® (CMD#48). The failure signal is not activated
for information and warnings.
Diagnostic functions (Monitoring):
• Plausibility of FRAM data
• Plausibility of ROM data
• Working range of internal reference voltages
• Signal detection of the measuring range of the internal sensors
• Temperature compensation of the internal sensors
• Calibration corresponding the application
• Plausibility of counting value
• Plausibility of physical unit, system and selected unit
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 29 Tuesday, April 12, 2011 10:17 AM