KROHNE H250 M40 EN - Manual (Page 31)

ELECTRICAL CONNECTIONS
4
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H250 M40
www.krohne.com 11/2012 - 4000640702 MA H250 M40 R02 en
Value range NAMUR
Range of values applies only when connected to a switching amplifier with the
following reference values:
• Open-circuit voltage Uo = 8,2 V DC
• Internal resistance Ri = 1kOhm
Range of values transistor output
To safeguard the range of values, a load RL between 250 Ohm and 1kOhm is recommended for
the passive transistor output with a nominal voltage of 24V DC.
If other loads are used, caution is advised as the range of values of the signal voltages then no
longer corresponds to the range of values for the inputs of process control systems and controls
(DIN IEC 946).
1 NAMUR terminal connection
2 Isolated switching amplifier
3 Terminal connection transistor output
4 Power supply U
ext.
5 Load R
L
Normally closed Normally open
Switching value reached ≤1 mA > 3mA
Switching value not reached > 3mA ≤1 mA
Signal voltages U
L
[V] U
H
[V]
lower Limit upper Limit lower Limit upper Limit
over load R
L
0 2 16 30
Signal currents I
L
[mA] I
H
[mA]
lower Limit upper Limit lower Limit upper Limit
Category 2 0 2 20 110
CAUTION!
The upper limit of the signal current may not be exceeded as this may damage the transistor
output.
MA_H250_M40_R02_en_640702_PRT.book Page 31 Wednesday, November 28, 2012 12:23 PM