Modbus libraries for LabView 8.0

[malef]

I can only talk about Modbus TCP/IP. Hardware communication works fine. Slave simulation is faulty.
I modified "MB Ethernet Example Slave.vi" and simulation works fine on TCP/IP.

See attached file

Manfred

[Christian_nor]

As you have probably realized by now, I'm not an expert in modbus. I have another question..

In the Modbus command you have some parameters called quantity and discrete, can someone explain these for me?

Btw, I think this is actually working, I just have to understand how...

Thnx

[unclebump]

Click on the modbus speciications button at this page.

http://www.modbus.org/tech.php

[Christian_nor]

Hi,

Need some help, again..   I'm loading measured values from my module, but when these values are negative, I get forexample 65522. Which should imply that I receive a hex number FFF2. But I want this to be represented as the negative number it is, refer to 2's complement. How can I fix this?

Thnx!

[Christian_nor]

BTW. The received number is 16 bit binary.

[Christian_nor]

I guess the .vi that needs modification is the: MB decode data.vi. I think I know how to convert a 16 bit number represented with 2's complement into decimal numbers, but where do I find the correct 16 bit number to translate..? And how do I convert a unsigned word of 16 bit

[Christian_nor]

I guess the .vi that needs modification is the: MB decode data.vi. I think I know how to convert a 16 bit number represented with 2's complement into decimal numbers, but where do I find the correct 16 bit number to translate..? How do I convert a unsigned word of 16 bit integer (0 to 65535) to bits I can work with. Is it possible to convert it to signed or something, so LV understands that it's dealing with a negative number.

Message Edited by Christian_nor on 11-25-2005 07:55 AM

[Donald]

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@Christian  wrote:

 How do I convert a unsigned word of 16 bit integer (0 to 65535) to bits I can work with. Is it possible to convert it to signed or something, so LV understands that it's dealing with a negative number.

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Apologies if I'm misunderstanding, but are you looking for something as shown in the attached?

[Christian_nor]

Super!! I was hoping it could be that simple! Thanks alot.

rgrds.

Labview amateur..

[wora]

Hi Christian_nor,

I have similar the same problem. Did it work in your case?

best regards
Wolfgang