Libra

The image above is an example of Libra's primary operation display. The display is divided into four main sections: three scale sections and the remainder of the display. The remainder contains the current assay values, a clock (at the top right), the program version (at the bottom right) and a menu of other functions that might be needed (at the top left). Each scale section contains two buttons that are used to tell the program when you star, update, or finish early a cylinder. There are also four buttons that control the horizontal scale of the graph presented for the scale. The vertical range for the plot is from zero up to the target full weight for the cylinder, rounded up to the next graph step.

The large value being displayed is generally the current weight from the scale, but the value might be adjusted or different at times. When a cylinder is being filled, the weight displayed shows only the weight of product added to the cylinder (the tare and heel have been subtracted). When a station is idle, the value is the actual weight currently on the scale. When the program encounters problems reading the value from a scale (or has not ever read a value, as shown above for Scale 29) a special text value may be displayed indicating the problem. The problems reported are:

Value Shown	Problem being reported
Xscan	hardware scan failure
Xover	overflow - voltage outside range
Xunder	underflow - voltage outside range
!read	value has never been read
!used	not configured or used
?xxx?	Unexpected error condition. The 'xxx' contains the numeric value encountered.  This value should be reported to the developers.

When the 'Start' button is pressed for a scale position in Libra's primary display, the initial settings panel is displayed and should look very much like the image above (some values may be a little different, since they are 'live'). The start time is filled in with the current time, but you may enter a different time if the cylinder was started earlier. The cylinder number is a required field made up of six alphanumeric characters. The values shown for Assay No. 1 and No. 2 are the current values from PICS (and they may even change while you are filling in this panel). The Tare Weight shows the current weight on the scale minus whe amount entered for the starting heel. If the Tare weight is displayed on a red background, it is outside the expected range for an empty cylinder, indicating that the value entered for the heel may be in error. The expected range may be adjusted using Libra's settings panel, described next.

The Settings panel allows runtime adjustment of some of the INI configuration values. Everything adjustable in the panel above takes effect when the OK button is pressed, while most of the other settings in the INI file are only processed when the program starts. If the new settings should be made permanent, don't forget to tell Libra to save the settings (using the Control menu).

When, for whatever reason, Libra is exited while one or more stations are active, the scale recover panel will be displayed when Libra restarts. This panel offers the operator a chance to enter the values necessary to get the program "back on track" (as it were) after the gap in the recorded data. The Advanced button exposes some additional options, as seen in the images above.

If it is discovered that Libra was told to record the wrong assay as input (or an incorrect/temporary manual assay was entered) it might be necessary to correct some of the samples that were recorded. The data correction panel allows this by displaying the existing samples in a tabular list. Select a contiguous group of samples to correct and press the 'Edit Samples' button to change the assay value used for those samples. The weight may not be changed.

The 'Edit Samples' panel allows manual adjustmeny of not only the assay selected, but the its value for the selected entries, too. The bias for those entries may also be changed. For auditing purposes, each sample includes a change count that is reported in the CSV file record of the cylinder filling operation, produced when the cylinder is finished.

If the selected assay value for an active scale strays outside the acceptable range, the Assay Alert panel will be displayed, offering the operator a chance to correct the assay for the sample. This often means that the assay inputs and/or the target assay for the cylinder should be checked. For example, a decimal place typo in the target assay will almost always trigger this panel.

The calibration panel was designed to help calibrate the two analog input scales. It does this by obtaining a set of readings for two different weights (optimally at opposite ends of the expected weight range) and determining the constants necessary for a linear equation to pass through both samples.

Left-clicking on any of the graphs will display the Change Plot panel (above). This panel allows the user to adjust the vertical step (Weight Increment) and all five of the colors used by the associated scale. This feature allows configuration such that each position is a distinctly different color scheme and therefore easily identifiable. These settings are also stored in the Libra INI file, so remember to save your settings if you want to keep any changes made in thie panel.