KEYENCE BL-600 Series User Manual
Page 115
105
Chapter 6 Functions for Reading Operation
6
■ Assessment criteria for PMI
The BL-600 Series assesses the PMI (Preventive Maintenance Information) in four
levels by calculating the multiplier for the scan count between laser emission start
and reading completion with reference to the specified decoding match count.
The BL-600 Series calculates the PMI using the following calculations.
The assessment uses two reference values (L1: Preset value 1, L2: Preset value
2).
*
Be sure to set L2 larger than L1.
Note: The scan count includes scans that are not applied to a bar code. If many
scan counts are not applied to a bar code, such as if using a raster-scan type
reader, increase the preset values (L1 and L2).
Example:
When the decoding match count is 2, preset value 1 (L1) is 5, and preset value 2
(L2) is 10:
•
Scan count for L1: 2 (Decoding match count) x 5 (L1) = 10
•
Scan count for L2: 2 (Decoding match count) x 10 (L1) = 20
As a result, PMI is assessed as follows:
•
10 scans or less
→ PMI = 0
•
From 11 scans to 20 scans
→ PMI = 1
•
21 scans or more
→ PMI = 2
■ Setting the PMI preset values
First, perform a reading rate check. Then, check the result and the following table
to determine the preset values. A reading rate of less than 20% is not included.
The above values should only be used as a guide. Select the optimal value accord-
ing to the operating conditions for a more severe or a more moderate criteria.
Reference: When the preset value 1 (L1) is set to “0”, there is no assessment
criteria for preset value 1, so PMI 1 will not be displayed. If the preset value 2 (L2)
is set to “0”, there is no assessment criteria for preset value 2, so PMI 2 will not be
displayed.
Trigger input
Scan count between laser emission
start and reading completion
Laser emission
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6