On-off control of multiple channels. Channels can be added as required and switching between their two possible states can be defined by toggling points on a grid or dragging regions of activity for fine control of timing.
Create a new target object with the menu at the top left. Then channels can be added with "add channel". Each is shown as a black bar initially, numbered at the right. By default the window allows the usual mouse driven scaling and translation. To modify the signals, change the checkboxes on the right from "scale" to "select". Click on the different channels to change regions from 0 (black) to 1 (white) or back. The size of the region which changes with one click is set by the slider at the bottom.
To get all the normal scaling features back, move the checkbox from "select" to "scale". Those functions that are unambiguous still work in "select" mode. In particular, scaling and shifting in one dimension at a time still works by clicking below or to the left of the data, which allows you to do everything in "select" mode with a bit of practice.
For more control of switching times, click and hold the right button on a white region and drag it into the neighboring black. The boundary moves with the mouse. To reduce the size, click and hold on the black and drag it over the white. Regions can also be merged or eliminated this way.
Each channel also has a control point on the y-axis. Clicking on this point puts a text representation of the channel in the text area on the left. The representation can then be edited. To make it take effect, use the apply button on the lower right. The format consists of lines of numbers optionally preceded by isolated "+" or "-" signs. The first number on each line is a time indicating that the state changes at that time: to the "off" state if preceded by "-", otherwise to the "on" state. If a second number is present this is interpreted as a duration for the change. The following three cases are equivalent:
+ 10 1 + 20 2
+ 10 - 11 + 20 - 22
10 1 20 - 22
Lines with other text in them are ignored. It does its best to resolve ambiguities in the numbering, but using the "+" and "-" convention is the easiest way to be sure.
What use is made of the various channels is up to the model they are attached to. At this stage they should just be considered as a set of boolean variables which change value at particular times. In IaFNetworks for example, if attached to a population of cells, they are mapped one-to-one onto the cells until cells or channels run out. In the "off" state there is no effect. In the "on" state they give a conductance input into the corresponding cell, with the conductance and reversal potential defined as part of the network.
NB: delete does not do anything yet.