Pausing Simulation with the Measurement Probe in Multisim

Multisim offers a number of advanced virtual instruments and analyses that help you gain a deeper and more complex understanding of the operation of your design.

The measurement probe is such a tool, and it can be both a quick and functional interface to the characteristics of your circuit, as well as an advanced tool to cutomize the simulation process in Multisim. The advanced features of the probe allow you to use the instantaneous voltages and currents at a particular node to access and display information in the Description Edit Box, and, as this article will investigate, pause your simulation.

The Measurement Probe

The measurement probe provides quick access to the voltage, current and frequency of a particular node during simulation and is an important feature for many designers. Multiple instances of the probe can easily be placed at any node of a circuit from the Instruments toolbar (circled in red in Figure 1).

Once a probe is connected to a node on a Multisim schematic, a yellow data region immediately communicates the time-varying characteristics of the circuit as shown in Figure 2:

The measurement probe's advanced features can also assist in analyzing and customizing the simulation of a circuit. For example, you can set your simulation to pause based on a pre-determined condition. This allows you to check that a circuit is functioning properly during set increments of simulation.

Placing a Measurement Probe

This example uses the Speechfilter.ms10 file, a sample file included with Multisim 10.

1. Select File >> Open Samples and open the Speechfilter.ms10 file.
2. Click on the Measurement Probetool in the Instruments toolbar. Notice that the mouse cursor has changed to the probe mode.
3. Connect the measurement probe to net 14 as pictured above in Figure 2 by left-clicking on the wire.
4. Notice that a new yellow field is now displayed on the schematic with the measurement labels for voltage (V), peak-to-peak voltage (V(p-p)) etc.

Setting a Simulation Pause

In the Probe Properties dialog box we can set the probe to pause simulation for a discrete amount of time when net 14 reaches a certain voltage value (in this case whenever we reach a value greater than 2V).

5. Double-click on the yellow measurement probe field and select the Description Box tab. The tab will look like the image below in Figure 3.

6. To add a pause condition, click on the New button (circled in red in Figure 3 above). This will activate the necessary input fields to build the final expression.


The condition at which an action will be taken can be entered in one of two ways. The expression can be manually entered into the Conditions field OR can be entered via pop-up menus, as described below.

7. To create the mathematical expression or condition, click on the arrow button (circled in blue in the Figure 3). This will display the following information displayed in Figure 4:

8. Select the Voltage heading in the pop-up menu. Notice that the value V has now been populated in the Conditions field.
9. Click on the arrow button (circled in blue in the Figure 3) and this time select the Operators heading. In the child pop-up menu select the > (greater than) sign. Notice that the Conditions field now reads V>.
10. Finally select the Conditions field with a left-click of the mouse and enter the value 2.

We can now select the action which will be taken when the condition is met.

11. Select the Action combo box (circled in green in Figure 3).
12. In the drop-down box select the Pause Simulation option.

Simulation will now automatically pause as soon as the voltage is at any value greater than 2V. We can now set the length of the pause, 5 seconds.

13. Select the Parameter field and enter the value 5.
14. Click on the Apply button.
15. Click on the OK button.

Simulate the circuit and notice in the measurement probe that at each point that Multisim simulates a voltage value greater than 2V at node 14, the simulator pauses. If multiple probes were placed in the schematic, this 5 second pause would allow any designer to quickly take stock of the characteristics of a circuit during simulation, ensuring that when node 14 reaches the pre-set condition there is an opportunity to check other currents and voltages of interest.

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