Configure the Termination Character for VISA Serial Reads

You can configure the termination character for VISA Serial Read VIs. You can use the End Mode for Reads property (also known as ASRL End In) to configure how VISA Read will stop reading characters. 

In order to configure the termination character for serial reads you must set the End Mode for Reads property or the VISA_ATTR_ASRL_END_IN attribute. 

1. Place a VISA Property Node on the block diagram.
2. Navigate to the below menu from the VISA Serial Read.

3. Right click on the property node and select Change All To Write
4. Right click on the input to ASRL End In and select Create » Constant to create the enumerated input. 
   • TermChar is the default output for ASRL End In, which stops reading after receiving a termination character.

Note: If you reconfigure the serial port using the VISA Configure Serial Port VI after you call this property and do not specify an input for Enable Termination Char the default settings will be enabled.

Your options to configure End Mode Reads are as follows:
 (0) None - (Default) The write will transmit the exact contents of the user buffer, without modifying it and without appending anything to the data.

 (1) Last Bit - The write will send all but the last character with the highest bit clear and then transmit the last character with the highest bit set.

(2) TermChar- The write will send the character specified as Termination Character after the data transmits.

A full explanation of how to use these options, including example snippets, can be found in the Tutorial: Termination Characters in NI-VISA.

Note: This image is a LabVIEW snippet, which includes LabVIEW code that you can reuse in your project. To use a snippet, right-click the image, save it to your computer, and drag the file onto your LabVIEW diagram.