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Active Participant
K C
Posts: 1,653
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Re: Serial com with USB485 - ModBUS

Hi Eric,

 

Maybe you can try to read an address and see what your slave returns.

 

The CRC calculation method is always the same.

 

Kees

Member
ethibault123
Posts: 31
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Re: Serial com with USB485 - ModBUS

Hi Kees,

 

I decided to try with the MODBUS library from labview because i was becoming crazy trying to write my own cmd...

 

Good news... I can read and write SOME registers...

 

I don't understant why, if you look at the register table i sent to you recently, I can do what ever I want from the list from page 72 to 85 (what they seem to call legacy parameters table).

 

But whenever I try to do read/write another address higher then 760 (40761), i have an illegal address error code. Any idea why?

 

Example: If I try to read the address 44804 (4803 from labview) I got the error.

 

Slowly... getting through it...

 

Thanks

 

Eric

Active Participant
K C
Posts: 1,653

Re: Serial com with USB485 - ModBUS

Hi Eric,

 

Had a long weekend. No computer no forums ... no NI

 

Now it is getting device specific. I see no reason why you cannot communicate with the mentioned addresses.

 

Kees

Member
ethibault123
Posts: 31
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Re: Serial com with USB485 - ModBUS

Hi Kees,

 

Yes, long and hot weekend (here in Canada). Warn weather is finally coming up.

 

Ok well thx a lot for your help, it helped me a lot.

 

You are good :smileywink:

 

Bye,

 

Eric

 

 

Member
No_RegreTs
Posts: 181
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Re: Serial com with USB485 - ModBUS

Could you please convert it to 2009SP1. I can't open 2011.


Yasemin Barutçu
Electrical And Electronics Engineer
Member
Courtney_L
Posts: 137
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Re: Serial com with USB485 - ModBUS

Hi Yasemin,

 

Which file do you need converted?

 

Best,

Member
ethibault123
Posts: 31
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Re: Serial com with USB485 - ModBUS

Hi

 

This one? Let me know if it works.

 

Eric

Member
No_RegreTs
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Re: Serial com with USB485 - ModBUS

Hello Courtney,

 

and Test2.vi would be great.

Yasemin Barutçu
Electrical And Electronics Engineer
Member
Courtney_L
Posts: 137
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Re: Serial com with USB485 - ModBUS

Hey Yasemin,

 

These should do the trick.

 

Best,

 

Member
No_RegreTs
Posts: 181
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Re: Serial com with USB485 - ModBUS

Thank you very much, they worked.


Yasemin Barutçu
Electrical And Electronics Engineer