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wt210

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This is my first time working with GPIB and it's been fun, but I have this Yokogawa WT210 power meter that doesn't seem to be updating on my VI more than twice per second.  I have other hardware running in parallel while loops with the AC power meter, those are all re-freshing very fast, but the power meter indicators are doggy and I dont't understand why.  I can successfully change the sampling rate of the meter through the string commands, but this has no effect on the VI front panel indicators.

 

Any ideas?  Here is the code.

 

If you are going to post example code please save it in 8.5   thx Smiley Happy

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Hi I have used a WT210 as well.

 

You forgot to attach your subVI...

Questons... is the integrator turned on?

How many bytes are being returned and sent to the meter at what baud rate? At 9600 baud its going to take 75ms to send your 72 byte read string.

Does the display on the meter update faster than your code?

 

For my application I think I get data a bit quicker than that.. .but generally I have found power meters to be slow. Also if you get much above 5 samples per second - it gets hard to read the indicator since its updating so often... at this point I think its better for the power meter to average it, but this depends on what you are trying to see.

 

 

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I've never gottent into this much detail with Labview and reading from hardware, so I need this drawn out in crayon. 

 

The power meter display updates faster than the VI.

I'll have to check what baud rate I'm at.

 

What is the purpose of the integration?  You do it over a time period, then divide to get the average? Is this something you set in the meter or in the code?

 

 

My goal is to display and be able to log the devices power consumption as we test it, in case you want to know my application. 

 

 

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Hi

can you please upload Yokogawa WT110  command.vi that the attached one calls?

 

These are the main points:

1) It takes time to send the command and recieve the response from the meter. LabVIEW cannot update faster than this.

2) Intergration is a feature on the power meter that averages power over time. If your load varies it can give more accurate results. For example a soldering iron draws peaks of power to keep the tip hot... In this case it is better to average Input power over time.  Other loads (e.g. motors at certain speeds) may draw varing amounts of power out a mains cycle. But  I don't think you are using this.

3) I don't think you have found this.... I based my code on it... download and have a play. http://sine.ni.com/apps/utf8/niid_web_display.model_page?p_model_id=1804

 

Regards

Nick

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Solution
Accepted by topic author krenik22

Here is the Yoko Command sub-Vi.   

 

 

When I run the power meter out of my main program loop, and just drop it into a blank Vi, it updates much faster, from 2Hz  to 10Hz.  (estimate).     Also, in my main program (several hardware loops running), I started adding other features: plots/data logging.   It starts crashing and locking up for a couple seconds.   I'm starting to think the PC is struggling?  Its a 2GHZ Pentium with 500mb ram.    How demanding is multiple hardware device control?  

 

I think I'll start another thread with my entire program posted, and get opinions.  I think my WT210 problems are solved, or atleast understood.

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Hi

great - pleased you are making progress.

I suspect at least one of your loops does not have any wait / delays and is running as fast as posisble. (You can verify with task manager).

You can also use labVIEW's profile feature to see what is using up memory / or being called a lot.

 

Nick

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