Data Sheet

Proteus VSM
223
Probe objects are like generators and most other objects in Proteus; the same procedures for
previewing and orienting the probe before placement, and editing, moving, re-orienting or
deleting the probe after placement apply (refer to the section on Probes in the reference manual
for more information). Probes may be edited in order to change their reference labels. The
names assigned by default are fine in our case, but a useful tip when tagging probes is to aim
for the tip of the probe, not the body or reference label.
Now that we have set up the circuit ready for simulation, we need to place a graph to display the
results on.
Graphs
Graphs play an important part in simulation: they not only act as a display medium for results
but actually define what simulations are carried out. By placing one or more graphs and
indicating what sort of data you expect to see on the graph (digital, voltage, impedance, etc.)
Proteus knows what type or types of simulations to perform and which parts of a circuit need to
be included in the simulation. For a transient analysis we need an Analogue type graph. It is
termed analogue rather than transient in order to distinguish it from the Digital graph type, which
is used to display results from a digital analysis, which is really a specialised form of transient
analysis. Both can be displayed against the same time axis using a Mixed graph.
To place a graph, first select the Graph icon: the Object Selector displays a list of the available
graph types. Select the Analogue type, move the mouse over to the edit window, click once to
start placement, drag out a rectangle of the appropriate size and click a second time to place
the graph.
Graphs behave like most objects in Proteus, though they do have a few subtleties. We will
cover the features pertinent to the tutorial as they occur, but the reference chapter on graphs is
well worth a read. You can tag a graph in the usual way with the left mouse button, and then
(using the left mouse button) drag one of the handles, or the graph as a whole, about to resize
and/or reposition the graph.