Settings - Analog Output

Mr. Kick supports the two analog output channels available on most E-series MIO-boards: For each channel you may output an analog pattern (waveform), which can be used to control an external device, e.g. a muscle stretcher.
A general overview of control outputs is available here.

The pattern is defined via analog output plug-ins (AOPI), and may be either the output from one plug-in or the sum of two - or turned off. The DC offset can be set per channel, whereas the trigger source and update rate is common to both channels.

1. General Parameters: D/A
2. Active - The concept of Plug-Ins
3. Offset, Sensitivity and Unit of Measure
4. Plug-In Set Up w. examples:
• Ramp-Hold-Ramp
• Pulse Burst Train
• File Playback

General Parameters: D/A

The analog output pattern will be sent to the digital-to-analog converter, D/A, at a certain rate when trigged. These parameters are set via the D/A control:

• AO Trig Source: The output may be synchronized to the acquisition of sweeps, Timer 0 / AD, or to an incoming trigger at PFI line no. 6, which could be connected to Timer no. 1 (or any other TTL compatible source).
• Update Rate is the rate at which the analog output is updated.

Note: If an analog output has been trigged, Mr. Kick will wait for it to finish before it starts another sweep or stops acquisition. As a result there may be a delay from when you press Stop until the program actually complies - the longer an analog pattern the longer delay.

Active - The concept of Plug-Ins.

Each of the two analog output channels may either be off or controlled by one or two plug-in(s).

If Active is set to Off that channel will output a DC voltage as specified by the Offset and Sensitivity controls.

If Active is set to Primary or Superimpose you must load and set up one or two plug-in(s) to specify the output pattern.
A plug-in is a separate piece of software that is loaded into Mr. Kick and run from there. The interface between Mr. Kick and the plug-in is well defined (described here), so that any LabVIEW programmer will be able to make his/her own plug-ins and in this way extend the program without having access to the source code. A number of different plug-ins will be available from SMI as well.

Setting Active to Primary means that only one plug-in, the first or primary, is active. Superimpose means that the output from the primary and the secondary plug-ins are superimposed, i.e. the sum of the two.

Plug-ins are loaded via the Load button and their parameters are specified via the SetUp button as described below.

Offset, Sensitivity and Unit of Measure

The Sensitivity setting represents the conversion of the voltage at the analog output channel into relevant units for the equipment attached to that channel; an example: A rotational stretching device is attached and for each Volt supplied it will turn (stretch) 4 degrees, then the sensitivity is 4. The unit of measure will then be degrees, and should be specified in the Unit control.

You can shift the baseline for the output via the Offset control either by adjusting the slider or typing in the value you want. - This has immediate effect!

Plug-In Set Up

Press the Load button to load a plug-in. So far these are available:

• Ramp-Hold-Ramp
• Sine-Hold-Sine
• Haver Sine
• Pulse Burst Train
• File Playback

When loaded the setup dialog will automatically open. This may be accessed via the SetUp button as well. As each plug-in may have different parameters to control their behavior, their setup dialogs will differ. The Ramp-Hold-Ramp setup is used as an example below. The Sine-Hold-Sine is equivalent, only the ramp up and down are sine patterns instead. Also the Haver Sine is very similar, except that it features no hold period.

Ramp-Hold-Ramp Example

The Ramp-Hold-Ramp pattern has been used widely to control stretching devices:
First the muscle is stretched at a specified velocity until some stretch amplitude is reached. This muscle length is maintained for a period, then the muscle is unloaded at another velocity to the original length.

The parameters of analog output plug-ins are subject to classification, if classification method is set to Stimulus Type and Act On to Analog Output.

If analog output is not classified only class 0.0 will be available, otherwise you choose the class for which to set parameters via the Class control.
Each defined class may have its own set of parameters, i.e. you could specify different stretch amplitudes or velocities (rise times) in different classes.
In the Ramp-Hold-Ramp Setup the following parameters are available:

• Active specifies whether a Ramp-Hold-Ramp pattern will be issued in the given class.
• Delay specifies if the pattern should be delayed in relation to the incoming trigger; measured in seconds. If two plug-in outputs are superimposed you may use this parameter to delay the one relatively to the other.
• Amplitude is the amplitude of the pattern in the hold period, e.g. stretch amplitude. If Sensitivity is set right this will be measured in proper units.
• Rise Time, Fall Time defines the duration (in seconds) of the rising and falling ramps respectively.
• Hold Time is the time (in seconds) from the end of the rising ramp until the onset of the falling ramp.
• Repetitions and Interval: The pattern specified by the above parameters may be repeated. The number of repetitions and the interval from the end of one cycle to the onset of the next is specified via these controls.

Edit All gives acces to a complete editable table of all parameters for all defined classes.
The Keep / Restore and Copy / Paste buttons feature the same functionality here as explained elsewhere.