Pepperl+Fuchs KFD2-UT2 Series Manual page 23

Functional Safety KFD2-UT2-(Ex)*(-1)
Operation
Proof Test for Output as Current Sink
The criteria for a successful repeat test, which are specified for the output as a current source,
are also valid for the output as current sink. In addition to the test setup described above,
a voltage source must be connected to the output to simulate the original application.
Proof Test Procedure for Output as Voltage Source
The resistor values which are used to simulate the potentiometer shall be chosen
so that they represent the full scale value of the potentiometer when connected in series.
The individual resistors shall be of the same resistance value and have an accuracy of 1 %.
1. Connect the series resistors for 0 %, 50 % and 100 % of the potentiometer value
to the terminals 2 and 3 (channel I) and 5 and 6 (channel II), see figure.
2. Connect the one-shot input to the terminals 1 (channel I) and 4 (channel II)
to the junction of the two simulation resistors.
3. Connect the digital multimeter to the terminals 7 and 8 (channel I)
and 10 and 11 (channel II).
4. Set the simulation resistor to 0 %, 50 % and 100 % of the potentiometer value.
5. Measure the output voltage
The proof test is passed if the output values are within 2 % of the output span.
This means:
– for 0 % of the potentiometer value: 0.9 V to 1.1 V
– for 50 % of the potentiometer value: 2.4 V to 2.6 V
– for 100 % of the potentiometer value: 4.9 V to 5.1 V
6. Remove the series resistors.
7. Set the device back to the original settings after the test.
Proof Test Coverage
The Proof Test Coverage
With  = 66 FIT (device), the proof test can reveal only 60 FIT.
du
is assumed to be min. 90 %.
device
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