Banner A-GAGE High-Resolution MINI-ARRAY MAHE6A Instruction Manual page 25

Number of Beams
Step Size 2 4 8
Minimum
Object
5 mm 10 mm 20 mm
Detection (0.2") (0.4") (0.8")
Size
Figure 5-14. The effect of step size on
minimum object detection size
NOTE: Scan times are exclusive of serial
communication transmission times.
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Double-Edge Scan is used to detect two edges of a single object, for example, box
width measurements. Double-Edge Scan requires the selection of a step size: 2, 4, 8,
16 or 32 beams. The sensor uses the steps to "skip" over beams. Double-Edge Scan
works as follows:
1. The sensor activates beam #1 (the beam closest to the sensor cable end).
2. The sensor activates the next beam, determined by the step size. (For example, if
the step size is 2, beam #3 is next; if the step size is 8, beam #9 is next.)
3. As long as the activated beam is unblocked (or "made"), the sensor will continue
the stepping routine until a blocked beam is found.
4. When a blocked beam is found, a binary search is conducted to find the object's
"bottom edge."
16 32
5. When the bottom edge is found, the sensor begins "stepping" again through the
array until the sensor finds the next unblocked beam.
6. A binary search is again performed to find the second edge.
40 mm 80 mm
(1.6") (3.2")
Note that this scanning method sacrifices object detection size for speed. Similar to
Single-Edge Scan, Double-Edge Scan has some restrictions: the object should provide
a solid obstruction; the size of the object will determine the maximum step size
(Figure 5-14).
Sensor response time is a function of sensor length and scanning method. Typical
scan times are shown in Figure 5-15.
Array
Length
163 mm
(6.4")
325 mm
(12.8")
488 mm
(19.2")
650 mm
(25.6")
812 mm
(32.0")
975 mm
(38.4")
1138 mm
(44.8")
1300 mm
(51.2")
1463 mm
(57.6")
1626 mm
(64.0")
1788 mm
(70.4")
1951 mm
(76.8")
Figure 5-15. The effect of sensor length and scanning method on scan time (typical)
Minneapolis, U.S.A. Minneapolis, U.S.A.
• •
Maximum Scan Times (in milliseconds)
Single-
Step
Straight Edge
Scan Scan 2 Beams
5.8 1.8 4.8
10.6 1.9 8.1
15.0 2.1 11.5
20.1 2.1 14.9
24.9 2.1 18.3
30.0 2.1 21.7
34.5 2.1 25.0
39.3 2.1 28.4
44.0 2.2 31.8
48.0 2.3 35.1
53.6 2.3 38.5
58.4 2.3 41.9
Control Module Configuration
Double-Edge Scan
Step Step Step
4 Beams 8 Beams 16 Beams
3.4 2.7 2.5
5.1 3.6 3.0
6.8 4.5 3.4
8.5 5.3 3.9
10.1 6.1 4.2
11.8 7.0 4.7
13.5 7.9 5.1
15.2 8.7 5.5
16.9 9.5 5.9
18.6 10.4 6.4
20.3 11.2 6.8
21.9 12.1 7.2
P/N 64118 rev. B
Step
32 Beams
2.6
2.7
3.0
3.2
3.5
3.6
3.8
4.1
4.3
4.5
4.7
4.9
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