Configure the Termination Character for VISA Serial Reads

Updated Mar 7, 2018

Reported In

Software

  • LabVIEW Base
  • LabVIEW Full
  • LabVIEW Professional

Driver

  • NI-VISA
  • NI-Serial
  • NI-488.2

Issue Details

Is there a way I can change the termination character for VISA Serial Reads? How can I configure the termination character for VISA Serial Reads?

Solution

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.
  1. Right click on the property node and select Change All To Write
  2. 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.

Additional Information

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.

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