Test Panel

With the Test Panel, you can read or write channel data for testing purposes.

To start the Test Panel, right-click on a channel in MAX and select Test Panel from the menu.

Interface

Use the Interface selection to determine which CAN interface to use for read or write of the channel. The Test Panel must be stopped using the Stop button to change the Interface.

The USB-847x CAN and LIN interfaces do not support direct reading and writing of channel data, and are not accessible through the Test Panel. If your CAN application requires channel access, refer to the Frame to Channel Conversion section of Chapter 6, Using the Channel API, in the NI-CAN Hardware and Software Manual.

Listen Only

This checkbox is available only for Series 2 hardware and only within the Read tab. When checked, the interface receives frames in a passive manner and does not transmit acknowledgements.

Read Tab

The Test Panel starts in read mode using the interface assigned to the message. The default sample rate is 1000 Hz. You can change the sample rate only after clicking on the Stop button to stop the reading.

Sample Rate

The sample rate specifies the rate at which CAN data is copied into the waveform. The value of every sample is set to the most recent value received on the channel for that time.

Note  When no data is received on the channel, the Default Value specified in Channel Properties is displayed for the channel. At such an event, the error indicator is yellow, indicating an old data warning (error code 0x3FF62009). This means the new displayed data does not contain any new information.

Scaling

You can set the chart to Fixed Scaling or Auto Scaling mode. In the Fixed Scaling mode, the maximum and the minimum values set in Channel Properties are used. When the user does not change the maximum and minimum values, the Test Panel uses the default range of 0 to 10. In Auto Scaling mode, the chart range is adjusted during run time to display the chart in the best possible way.

Error Indicator

The error indicator is gray when no errors are detected. Yellow indicates a warning. A warning does not stop the reading or writing. Red indicates an error, and the reading or writing is stopped. For more details on a warning or error, click on the Details button below the indicator.

Write Tab

To change to write mode, click on the tab above the chart display. This is possible only when you stop the reading. With the pointer slide, you can set the value to be written to the channel. For Boolean values (using one bit in the message), a switch is used instead of a slide.

For other channels in the message, the Default Value set in the Channel Properties dialog box is written.

The CAN messages are written at the sample rate set on the left side of the panel. If a sample rate of zero is selected, frames are transmitted by clicking on the Send button. This is the default. For nonzero sample rates, the frames are transmitted periodically, and the Send button disappears. If the sample rate is too high—depending on the baud rate, message size, and bus traffic—error 0xBFF62102 is displayed indicating that a sample rate or duration is too large or too small.