KROHNE BM 70 M - Manual (Page 9)

BM 70 M 9
BM 70 A
HART specific software
and operating devices
Converter
HART-
HHC
HART Communicator
HART FIELD COMMUNICATIONS
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HART-Master
Tank Inventory System
4 ... 20mA
+ HART ®
Modbus
PROFIBUS-PA
...........
Other
communication interfaces
RS 485
RS 485
4mA (Ex i)
+ HART®
PC-CAT
or
HART Communicator
HART FIELD COMMUNICATIONS
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HART-
HHC
Overview of digital Communication possibilities:
Point-to-point Multidrop
4.2 Ex-e current output HART
®
Function Level, distance, volume (conversion table) or reflection, and error
identification; galvanically isolated from digital input and switching
output
Current 4-20 mA; without or with error message (2 mA and 22 mA)
Accuracy/linearity 0.05 % (rel. 20 mA; at T = 20°C, 100ohm load impedance and nominal
operating voltage)
Temperature drift < 100 ppm/K (typically 30 ppm/K)
Load impedance < 500 ohm
Effect of load
impedance < 0.02 % (rel. 20 mA for RB = 0...500 ohm)
Effect of power 0.02 % (rel. 20 mA for UB within limits of tolerance)
Hazardous-duty
version Ex e
Note together with switching output and digital input
Digital input (terminals 81/82):
Can be used to suspend the entire measurement procedure, i.e. measurements are "frozen"
(standard setting), or to hot start the device (reprogramming by KROHNE Service).
Applicable voltage 5...28 V DC
Input resistance > 1 kohm
Switching output (terminals 41/42):
Can be programmed as a limit switch, alarm contact or error message. The contact is open in the
de-energized condition.
Operating data max. 100 mA / 30 V DC or 30 V AC
Internal resistance < 20 ohm