VISA Read.vi time out

[xgatc]

Hello,

I recently happened to use Labview Drivers from NewPort (ESP301) and Lakeshore (Lsci218) and I encountered the same "time out" problem whenever a subVI from the driver calls VISA Read.vi for serial communication.

I first thought there were problems with the Labview driver provided by the manufacturers, but having tried different LV driver from different company, I began to think that the problem might be the VISA Read.vi itself.

I am using LV2010-spring, also tested with LV2011SP1. Both give the same time out problem.

I asked the companies about the problem, they have not found answer, neither do they have LV2010 or LV2011.

Has anyone had the similar problem ? 

Attached VIs are FYI for  what I tested.

"test 218 initialize.vi" is from Lakeshore 218 driver, with a modification of adding "\r\n" to the "*IDN?". this subVI calls VISA Read.vi. and has time out error.

"test 218 initialize-md2.vi" has the same function, but calls VISAWriteRead.vi  instead of VISA Read.vi. and works OK.

How do I know that VISA Read.vi in LV2010 or LV2011 is working properly? or Can I replace the VISA Read.vi with LV8.6 one? 

It seems to me that Newport and lakeshore's LV driver were developed under LV version not greater than 8.6. and I believe that they must have tested their driver before release it or I hope so.

any suggestion is very much appreciated.

xiaofeng

[Dennis_Knutson · Accepted solution]

The LabVIEW version is irrelevant.

In the Read/Write, you are appending LF/CR. In the other, you appending CR/LF.

Avoid the platform dependent End of Line Constant in instrument communication.

[xgatc]

Hi, Dennis

Many thanks for the reply.  It was a mistake to use End of Line Constant.  I will have another go to use CR/LF to see what happens and let you know.

By the way, I did read your post in "Lakeshore 218 Temperature monitor will not Initialize"   and downloaded your HP86xxA Initialize.vi.

With lakashore 218, the user manual states that only BAUD rate needs to be set from front panel.  The 218 initialize.vi does not set anything, like what is done in your HP86xxa initialoze.vi for baud rate, data bit stop bit ...etc.   is it that lakeshore LV driver is used for GPIB not serial port?  if I want to use it  for serial port, do I have to modify it in the similar way as HP86xxA initialize.vi did?

cheers

xiaofeng

[xgatc]

Hi, Dennis

I have tested with all CR/LF as terminator. After calling VISA configure serial port.vi, it all works now for RS232 serial interface.

attached Zip file is the working example of ID query.

thanks again

cheers

xiaofeng