Communication fails with ILT1700-USB irradiance meter

[LTBALAZS]

Hi,
I have two instruments: ILT1700 USB irradiance meter, and Yokogawa power analyser.

Cases:

Case 1: reading both instruments in one while loop. Loop delay: 1 second.
When i start to read from the instruments at 1s interval, i have laggish answer from ILT1700 or i cannot read data out of it. Yokogawa works.

Case 2: reading instruments in two separate while loops:

Loop1: one is as "main' which reads the start/stop button, outside of it, there is another while loop for ILT1700.

Loop2: I found that i can read the value from irradiance meter real time only if there is no loop delay in Loop2.

For some reason I loose the communication with ILT1700 sporadically. It can occur sometimes after 80 measurements. If it happens i must restart and often unplug the device from computer. There is no affect of VISA close function inside while loop.

I did the following steps:

- I installed ferrite cilynder on the power line of the ILT1700 instrument,
- replaced USB cable to double shielded and ferrite cilynder cable,
- reinstalled appropriate labview runtime engine on target PC,

- turned off power save settings of USB on target PC,
- Installed appropriate NI-VISA driver on target PC,

- installed ILT1700-USB windows driver on developer and target PC,

- installed ILT1700 labview driver on developer and target PC.

I attached the manuals.

Can two while loop system cause communication problem?

Kind regards,
Balázs

[GerdW]

Hi Balazs,

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@LTBALAZS wrote:

I attached the manuals.

Can two while loop system cause communication problem?

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There are no attachments.

As you also did not attach your VI(s) we can not determine possible reasons for your problems!

[LTBALAZS]

Hi GerdW,

I attached my VI as Test.vi. Note this is a simplified vi. You can find the manufacturers' vi in the attachment as ILT1700.vi. You can see the manuals as attachements as well.

I today got the following error when communication failed:

Then pushed "Stop" button, then "Start". No affect on operation, error above stil occured. I tried it many times. Then unplugged the ILT1700 from usb and started the Test.vi again.:

I also find it strange that error of any kind occurs when starting and stopping data acquisiton. I had trouble free data logging with original VI for 16 hours.

Kind regards,
Balázs

[GerdW]

Hi Balazs,

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@LTBALAZS wrote:

I also find it strange that error of any kind occurs when starting and stopping data acquisiton.

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A framing error can occur when you start the VISA port while your device is right in the middle of sending a message. Don't worry, just handle the error by closing/opening the port again.

The TimeOut error occurs when your device does not send any message at all (within the defined timeout delay): you need to handle that error as well! Either wait more time or command the device to send data…

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@LTBALAZS wrote:

Then pushed "Stop" button, then "Start". No affect on operation, error above stil occured. I tried it many times. Then unplugged the ILT1700 from usb and started the Test.vi again.:

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The ILT1700 loop does not read this stop button, so it will not even attempt to react on it…

Your VI should be simplified even more, see the image for ideas:

(That "NaN" filter subVI can be called in a FOR loop before the IndexArray node…)