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Remove Serial Header Rs 232

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I need to remove the header from the serial data pack being sent by my Labview PC using VISA through a COM port.  I am using a simple 8N1 packet.  Is there a property I can change so that only the data bits and stop bit are sent?

 

I have attached my VI and an image of what the oscope capture looks like.  In this case I am sending 0x72 to be received by the test unit.

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I see nothing to help you.  What happens when you send 0x00 or 0xFF.  Is the issue you are seeing is the start bit?  Other option may be send the serial break. A serial break is intended to send a "space" for rmore than one character time.  That is all I have for you.

 

 

Matthew Fitzsimons

Certified LabVIEW Architect
LabVIEW 6.1 ... 2013, LVOOP, GOOP, TestStand, DAQ, and Vison
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Accepted by topic author TitanLabview

In my experience only the data and stop bits are sent, anything else over RS232 is handshaking - so do you have any flow control turned on? The other thing I'm concerned about is your transfer to a hex string, I'm wondering if what you are actually writing isn't what you think you are writing. For example, I fed your code through a feedback RS232, and I wasn't sure I could make sense of it. Have you tried simply using the Hex Display on the strings to begin with? (it's in the right click menu) I also don't understand why you have the conversion to a number in there - what is that meant to achieve?

 

I'm not sure that my questions make sense, but think about what you are actually writing, try the simlest version of an array of hex strings and sending them directly with no conversions.

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Hmmm, I can't see your code, but maybe a better way to approach the problem is to include what the make/model of your data instrument is.  Maybe some already has the answer for you.  🙂

Bill
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Changing the array to use Hex display fixed the problem. Thanks Kathryn!

 

I guess a bunch of extra bits were being tagged onto the front since I was using a 32-bit int for converting.  (Didn't know about the Hex display property)

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