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Set up voltage, current or other command Profiles. Points can be added singly or in predefined groups and sections of a Profile can be cut out to define new groups. Points can be positioned relative to any other point in the Profile so a range of different scaling behaviors can be achieved.
A Profile is defined as a set of points of increasing x coordinate and a series of relations between them. The possible relations are that a point should always take one or both of its coordinates from some other point or that it should follow some other point at a set distance in either direction. Points are allowed to take one coordinate from one point, and the other from another point.
Editing operations are provided to add and remove points and to set up and remove relations between them. New points may be added by dragging one of the symbols on the top row until it sticks to the current Profile. By default there are only two possibilities: a square pulse and a single point but you may create your own and share them between Profiles with the copy function below.
The possible operations correspond to buttons on the right. Moving the mouse over them should put a brief explanation of what they do in the top of the window. In particular, the top line allows a choice between the normal scaling operation of the box cursor and its use for selecting sections of the current Profile for editing. If you normally use the box cursor scaling then only switch it to select mode when you mean to select a portion of the Profile and switch it back afterwards.
The "snap" button allows setting a background grid on the window such that only values on the grid on one or both axes are allowed. This makes it easy, for example, to set completely flat baselines. A neater way of doing the latter however is to tie the y coordinates of all points that you want to be on the baseline to the first point. To do this click "y-tie", then click the point you want to be tied and the one you want it to be tied to in that order. To undo any of this tying use the free option.
Any time you select a point to move it, its coordinates appear in the two sliders below the canvas. If it is fixed in one or both directions (tied to another point) the corresponding slider will be grey. Otherwise the sliders may be used to set the position of the point with their usual functions. If you position the mouse over a slider and begin to type a number it will change to a text field to receive the keyboard input. Hitting return makes this value take effect.
The first two icons in the top panel are for a square pulse and a single point respectively. The third is a single point that represents a break in the Profile. This is useful where there are brief periods of activity with long constant regions between. The constant periods may be constructed with the break component, their durations being set from the slider labelled break. When drawing the Profile the expand checkbox selects whether to show the full Profile with the breaks taking their full space or a collapsed version, showing one section of activity directly after another.
Some components also use sampling information defined in the Profile. This is set for individual points with the sample slider. Each non-zero sampling interval applies until a later point overrides it. Thus, to set a single interval for the whole trace, only the first point needs to be set, but to set a coarse interval for most of a trace with a finer one for a segment in the middle, the first point should be set coarse, the point at the beginning of the fine section should be set fine, and the coarse sampling should be reset after the segment. The actual sample points to be used are shown if the samples checkbox is selected. Note, however, that the sampling shown corresponds to the full expanded trace, as shown with the expand checkbox selected, and will not tie up with a trace which contains breaks drawn without the expand option.
There is also an alternative way to construct Profiles. Instead of dragging predefined components and sticking them on, you can add points by realizing proto-points on the current Profile. The real points are drawn with colored circles. Between each pair of real points is a proto-point marked with an orange square. To make it into a real point, just click on it and drag it to where you want it. As soon as it becomes a real point, two new proto-points appear on either side. These in turn may be clicked and dragged to where you want. For regular shapes, it is probably a good idea to set a grid to only allow certain positions (see snap below).
The disadvantage of this process for simple shapes is that you don't have any structure in the resulting shape: if you make a square wave and then attempt to change the amplitude, each of the points at the top will move independently. Here you can use the x-tie, and y-tie options to link x and y coordinates. For example, the second point on the top of a square wave should be linked to the first in the vertical direction (click y-tie then the second point then the first). This will allow the height of the rectangle to be controlled with only one point.
Alternatively, change to select mode, pull a box out containing the square section and press group. This will convert everything in the box to a single Unit with control points for position, width and height.
The "sstruct" and "lstruct" buttons are a partial solution to this problem, particularly for Profiles loaded from files. They perform strict and loose structuring respectively. Points at the same, or nearly the same, position along one or the other axes are tied together and other points are converted to relative positioning instead of absolute. The results are not always what is required, but can save some of the editing operations.