Rif.: RS-485 Communication using VISA

[pincpanter]

The free library RTSLVU gave you a link of in message #3 is (kind of) open source, that is you can open the block diagram of all vi's and learn how to implement the protocol.

[IamAbhishek]

I have MODBUS library and used it successfully but I want to do same thing using VISA VI's.

I have attached  new VI using VISA and sending command to read  but still not able to read please check.

[IamAbhishek]

I Have already used modbus library for communication and was successful ,which i have already attached image in 1st post .

But I want to do same thing using VISA.

[pincpanter]

Then I guess you need to compute and send a valid CRC value.

[rolfk]

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@IamAbhishek wrote:

I Have already used modbus library for communication and was successful ,which i have already attached image in 1st post .

But I want to do same thing using VISA.

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Considering that the NI Modbus library uses internally VISA too, this sounds a bit weird. And anyways if the NI Modbus library works for you, you simply need to learn what it does and how. No amount of online forum help can solve that better for you than the working code of an existing library. And I have to admit that my motivation to dig into non-working code that you haven't even posted yet for a library that exists ready made and working, is very low.

[pincpanter]

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@rolfk  ha scritto:

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@IamAbhishek wrote:

I Have already used modbus library for communication and was successful ,which i have already attached image in 1st post .

But I want to do same thing using VISA.

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And I have to admit that my motivation to dig into non-working code that you haven't even posted yet for a library that exists ready made and working, is very low.

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Actually, he posted something, but it's very crude. All fields are constants, no CRC calculation, the answer is read as whatever is available in the serial input buffer after waiting 4 seconds, the answer is not interpreted... IMHO it seems a rather useless exercise.

[Frozen]

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@pincpanter wrote:

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@rolfk  ha scritto:

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@IamAbhishek wrote:

I Have already used modbus library for communication and was successful ,which i have already attached image in 1st post .

But I want to do same thing using VISA.

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And I have to admit that my motivation to dig into non-working code that you haven't even posted yet for a library that exists ready made and working, is very low.

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Actually, he posted something, but it's very crude. All fields are constants, no CRC calculation, the answer is read as whatever is available in the serial input buffer after waiting 4 seconds, the answer is not interpreted... IMHO it seems a rather useless exercise.

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Sometime it is useful to code up a web page using notepad so you better understand the black-magic tool kits 🙂

[rolfk]

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@Frozen wrote:

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Sometime it is useful to code up a web page using notepad so you better understand the black-magic tool kits 🙂

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Considering that the NI Modbus Library is open source, I fail to see any black magic there. It mostly comes down to being able to copy code correctly.