Difference Hold Mode; Measured Value Hold Mode - Pepperl+Fuchs 3RG7256-3NQ00-PF Instructions De Service Et De Montage

Mounting and
operating instructions

Difference hold mode

When the difference hold function is activated and Q
mum and maximum value of the measuring signal and stores it.
If Q = ­U , the last differential value is transmitted at the analogue output.
1 B
Example of use: Checking the contents of open containers or packages.
100% (20 mA)
0% (4 mA)
100% (20 mA)
0% (4 mA)
+U
B
Q
1
­U
B
B
Illustr. 16
15500149

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 change­over of work piece when machining.
Behaviour of analogue output with and without measured value hold.
Start of measuring range
End of measuring range
100% (20 mA)
0% (4 mA)
100% (20 mA)
0% (4 mA)
ON
Good Target Q
2
OFF
Illustr. 17
15500154
3RG7256­3NQ00­PF Distance sensor ­ 068­13787 / 45­3489 ­ Stand: 03/2011
2
1
1
A B A
With measured value hold
Without measured value hold
t(s)
= +U , this function detects the difference between the mini­
1 B
1 12 mA
2 2 mA
2
Q = +U
A
1
Q = ­U
B
1
B
= Sample. Collect measured values
B
= Display. Last maximum of analogue signal at
B
analogue output
37