IO Tech Digital 488 commands for LR-400 AC bridge's 408 IEEE interface card

[yash]

Hello,

We have an old AC bridge (LR-400) with IO Tech Digital 488 card in it. This card communicates with the IEEE interface card 408 of the AC bridge. The command were given in the QUICK BASIC commands. E.g.

PRINT #1, "OUTPUT 18;C2XF3X"

Where 18 is the GPIB address and C2X is the command for configure the AC bridge LR-400. The F3X is the command for the data format in ASCII DEC.

Similarly the command,

PRINT #1, "OUTPUT 18; P2XD";D1%;"ZXP1XD0ZXH2X"

Here P2 is the port 2 of the IO Tech Digital 488 card. D1% is the variable for a perticular setting. P1 is the port 1 of the Digital 488 card And H2X is the command for trigger. Here X is used for terminating the execution.

We are trying to give these command through GPIB-USB using Labview 2010. But so far not able to send any configuration commands to the intruments. Couple of VI's used are attached here.

Looking forward for suggestions and feedback.

Yash 

[yash]

Hello,

Finally I managed to make something to communicate with the LR-400.

This LR-400 is a 1989 model of Linear Research Inc., four wire AC resistance bridge. Having an IEEE interface cards 408-488(LR make) and IOtech Digital 488 (IEEE 488 to Digital I/O Interface). Labview version 2010. 

The attached library file has all the requisite files to read and write data to LR-400. This was tested in the range of 20 Ohms, 200 Ohms and 2KOhms range. The auto range has been included in the vi itself.

Looking forward for the feedback.

Yash 

[yash]

Hello,

Here is a little updated one.

Yash

[Dennis_Knutson]

You really want to add the error in/out clusters to your connector pane and use those instead of that silly stacked sequence structure. You would also eliminate all of the local variables. In your VISA-TEST subVI, you've made the mistake of wiring the return count of the VISA Write to the byte count of the VISA Read. There is absolutely no correlation between the number of bytes you have wriiten and how many you expect to read. If you are getting the correct results, it's just a matter of dumb luck.

[yash]

Dear Dennis,

About the second point. i.e. VIS-TEST. You are absolutely right that there is no need to wiring the return count of VISA Write to the byte count of VISA Read. But in this old LR-400, I am reading 3 port (with the command P3X, P4X, P5X) of 8 bits each, so it is sufficient to the return count and byte count of VISA.

I guess your first question refers to the LR-400-Read.vi. Yes, there are too many variables. Agree that its not a good way. But sorry did not get you suggestion. Will be thankful to you if you modify this LR-400-Read.vi (or any other) and post the same.

Yash 

[Dennis_Knutson]

You are just making an excuse for bad style if you wire the return bytes to the byte count. It's sloppy programming.

I'm referring to all of your code. You simply wire the error in/error out clusters to the connector pane. You use those to enforce dataflow and get rid of the stacked sequence structure. You also use the VISA Resource In/Out and wire them up as well. At least give it a try making the mods

It does not look like you have used LabVIEW before so you might look at the tutorial.

[yash]

Dennis Knutson,

Thanks for the great comments. Will surely try to incorporate your suggestions.

Yash

[yash]

Dennis Knutson,

Tried to implement some of your suggestions. I still feel that there may be some more sloppiness as per your. Would like to hear the same.

Looking for more feedback.

Yash 

[luobo]

Thanks, your suggestion helped a lot to make the instrument work. We use your strings to build a LUA libray to read out the LR400 remotely. Thank you!