FT 80 RLA Distance sensor - 068-13715 - 04.05.2009-03
Mounting and
operating instructions
37
Difference hold mode
When the difference hold function is activated and Q
1
= +U
B
, this function detects the difference between the mini-
mum and maximum value of the measuring signal and stores it.
If Q
1
= -U
B
, the last differential value is transmitted at the analogue output.
Example of use: Checking the contents of open containers or packages.
Analogue value
Analogue output
Measured value hold mode
When this function is activated, the last valid measured value is saved.
When no object is in the measuring range, the last valid measured value is transmitted at the analogue output. The
current value is only displayed again when an object is within the measuring range (OK LED = on).
Example of use: Maintain position of tool during change-over of work piece when machining.
Behaviour of analogue output with and without measured value hold.
Start of measuring range
End of measuring range
With measured value hold
Without measured value hold
Q
1
= +U
B
= Sample. Collect measured values
Q
1
= -U
B
= Display. Last maximum of analogue signal at
analogue output
A
B
B
B
B
A
A
100% (20 mA)
0% (4 mA)
0% (4 mA)
12 mA
2 mA
1
1
2
2
1
2
100% (20 mA)
+U
B
-U
B
Q
1
100% (20 mA)
0% (4 mA)
0% (4 mA)
100% (20 mA)
Good Target Q
2
Illustr. 16
15500149
Illustr. 17
15500154
ON
OFF
t(s)