• Measured area length – This is a measurement of the length of the area to be corrected. The measured area length should always be greater than the expected product length.
• Measured area length offset – This is a measurement of the offset from the center of the scan line to the center of the measured area length.
• Measured area width offset – This is a measurement of the offset from the center of the scan line to the center of the measured area width.
Control Zones Configuration Window
Figure 30 Control Zones configuration window
These settings allow segmentation of either the product or the full scan width data into a series of up to 14 zones. The Control Zones configuration window defines each of the 14 zones in terms of their position and which statistical calculations are
required.
Used in conjunction with the Hot Edge Detection function, zones can track a moving product.
For fixed zones which overlap the hot product edge, the function is derived from the hot product portion of the zone only.
A zone that is OFF cannot calculate data for the alarm and output channel
associated with it, thus the alarm will be turned off and the analog outputs will be set to 0mA.
Product Tracking
This option configures each individual zone to either track with the hot product if enabled, or align with the scanner field of view and thus the industrial process.
Units
The zones can be defined in either percentages or the measurement units of the system.
Reference
Each zone can be defined relative to a reference position. The reference options are
"Start, Centre or End". Percentage zones are always referenced to the start of the hot product or the start of the scan width. If Product Tracking is enabled, the
reference positions apply to the hot product and if the Product Tracking is disabled, the reference positions apply to the full scan angle.
Figure 31 Use of Track Product With Reference
Start & End
These define the size and position of each zone. The values must be specified in the units selected for each respective zone.
Percentage Units:
When defining a zone using percentage units and Product Tracking is enabled, 0% to 100% would represent the width of the hot product as identified using the hot edge detection algorithm.
This method would be used for a zone across the product width which may be varying or where the product moves about within the scanner field of view whilst being processed. 0% is the start reference point and 100% is the end reference point.
Percentage defined zones can be specified to 0.1%, allowing a resolution down to 1 sample.
Distance Units:
When defining a zone using specific units of measurement two forms of data can be obtained: product related or process related.
If Product Tracking is disabled, then the zone reference allows a zone to be fixed with respect to the process, for example yielding data from an area cooled by a fixed position vent.
If Product Tracking is enabled, then the zone reference allows a zone to be fixed with respect to the product, for example, yielding data from an area adjacent to each hot edge.
The range of a zone which starts at a reference point will have one value of 0 and the zone size will be determined by the second value. A zone in proximity to a start or end point reference point will have two values describing the zone start and zone end positions. A zone referenced to the centre has one value describing the zone size symmetrically about the centre of the product or process.
When measuring in mm the range is detailed in mm but will be dependent upon the tilt angle of the scanner and the distance from the scanner to the target as setup in the scanner configuration.
Figure 32 Zones Setup Schematic Diagram (Percentages)
Function
For each line scanned the processing for each zone can be independently set to one of the following functions.
Off No output.
Minimum
Finds the minimum temperature of all the samples within the zone.
Average
Calculates the average of the samples within the zone.
Peak
Finds the maximum temperature value of all the samples within the zone.
Quantile
This function performs a peak sample rejection algorithm to remove unwanted samples from the zone value. Firstly the samples from the zone are sorted into order of temperature values. These samples are then converted to a percentage value 0%
to 100% where 0% represents the sample value at 0% of the samples and 100%
represents the value at 100% of the samples.
input field.
Figure 33 Quantile Zone Function
Avg Threshold
The Average Threshold function performs a similar function to the standard average function with the addition of the ability to define a threshold level for the calculation.
The minimum and maximum temperature value in the zone is used to create a percentage index representing the threshold temperature. Only values that are above the threshold value are included in the average calculations.
Figure 34 Average Threshold Function
%F
This setting is used to set a parameter of the currently selected function. The input is only enabled when the function requires this parameter.
Zone Alarms
These settings are only applicable where the Processor has alarm relay outputs installed. They allow configuration of a maximum of 14 alarm relay outputs, each of which will be activated at a threshold temperature value by the corresponding zone processed temperature. If the associated zone 'type' is set to Off then there is no zone data on which to activate the alarm, and the alarm relay output will be set to OFF.
Level This value is the threshold level at which the alarm relay will switch. It may be set to any temperature within the range of the Landscan head selected in the
Linescanner menu.
Mode Select either Off, High or Low for the alarm trigger mode:
Off - The alarm will not activate under any circumstances.
High - The alarm relay will activate when the corresponding statistically calculated zone temperature is higher than the temperature threshold level.
Low - The alarm relay will activate when the corresponding statistically calculated zone temperature is lower than the temperature threshold level.
Output Enable
This is only applicable where the Processor has alarm relay outputs installed. It allows the enabling or disabling of any of the analog output channels that have been configured in the Processor system. A disabled channel will output 0mA. Where channels are known not to be installed, it is recommended that the user should disable their outputs in this part of the table. If the associated zone type is set to OFF
then there is no zone data to write to the current outputs and therefore they will be set to 0mA.
The Processor will accommodate a maximum of 16 analog output channels. The first two channels are dedicated to remote control of the Landscan head scan speed and emissivity, leaving a maximum of 14 remaining channels for zone outputs.
Time Zone Function
Generally, the application of a Time Constant Function creates a processing zone area over the moving product. This zone area is dependent upon the scan speed and the value of the time constant. For example, if the scanner is set for operation at 10Hz and a time constant at one second is used, then the zone area will cover ten scanned lines of the product.
Figure 35 Zone Time Functions
Apply
This turns on the time constant calculations for the zone peak picker, valley picker, and zone average.
The time functions are very useful for scanning a material with heavy scaling, or a narrow material such as wire. With the Time Function applied, zone processing functions are applied to an area of the product. This 'area' keeps pace with the incoming scan data, rolling forward as a block as each new scan line is processed.
Time Constant
This is the time value used in the zone time functions and is selectable between 0.04 and 60 seconds.
Zones Time Function explained: The values of Min, Avg and Peak are re-calculated continuously by taking the values re-calculated for each scan line and applying the zone time constant.
Off
The zones time function is disabled.
Minimum
This selects the valley picker function, where the zone output decays to the scanner lower temperature within the time constant period. This function is useful for ignoring 'hot spots' caused by surface changes with galvanised products.
The zone output will follow the minimum temperature within the zone area. Each scan line is processed in turn, if the next scan line has a minimum temperature lower than the previous scan line within the chosen zone then this new minimum value is used for the zone output. However, if the next scan line has a minimum temperature higher than the previous scan line within the chosen zone then a time constant is applied to the zone output.
Peak
This selects the peak picker function, where the zone output increases to the top Scanner temperature within the time constant period. This function is useful for ignoring scale or gaps in wire.
The zone output for this option is similar to the Minimum zone option except that the action is reversed. The zone output will follow the maximum temperature within the zone area. A time constant is applied to the zone output if the temperature is falling.
Average
This selects the running average function, calculated as the average of the individual averages of each line for the number of lines within the time constant. This has a smoothing effect upon the zone data.
Analog Outputs
Current Output
This determines the current range setting of all of the LPU’s Analog Outputs
Hold Outputs between products
If On, the analog outputs will hold the output values from the last hot product detected using the zone model selected. If Off, the outputs will represent whatever is
calculated by the corresponding zones. i.e. If there is no product within the field of view of the scanner, the outputs will read the background temperature. Note that if Hold Outputs between products is On the alarms will also hold their values until the next product is detected.
Figure 36 Zone Time Function Output