Getting Started with Modbus over RS485 (LabView)

[Michael_Smith]

Hello NI Community,

I was thinking about implementing Modbus on LabVIEW. I need your suggestions to start with.

I'm also hoping that if someone has already done it. What approach they adopted? (Can share block diagram or VI)

[GerdW]

Hi Michael,

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@Michael_Smith wrote:

I'm also hoping that if someone has already done it. What approach they adopted? (Can share block diagram or VI)

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There are ready-to-use Modbus libraries on VIPM. They come with example VIs…

[ZYOng]

Use NI Modbus Library Toolkit for LabVIEW

[StuartWilson]

I used the NI Modbus Library in VI Package Manager. In my case the code for creating a serial master and reading registers of devices looked like this: 

[Michael_Smith]

Hello Stuart,

I was planning to work around it on LabVIEW RT or FPGA. Those VIs will work in beforementioned? 

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@StuartWilson wrote:

I used the NI Modbus Library in VI Package Manager. In my case the code for creating a serial master and reading registers of devices looked like this: 

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[StuartWilson]

Never needed to do it on RT, but I'm pretty sure it will work the same. FPGA?
https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z000000P9GYSA0&l=en-US

[GerdW]

Hi Michael,

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@Michael_Smith wrote:

I was planning to work around it on LabVIEW RT or FPGA. Those VIs will work in beforementioned?

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On RT the Modbus libraries can work.

How do you want to access the Modbus messages on a FPGA? Which hardware do you plan to use?

[Michael_Smith]

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@GerdW wrote:

Hi Michael,

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@Michael_Smith wrote:

I was planning to work around it on LabVIEW RT or FPGA. Those VIs will work in beforementioned?

---

On RT the Modbus libraries can work.

How do you want to access the Modbus messages on a FPGA? Which hardware do you plan to use?

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Hello Gerd,

I'm planning to interface Servo Drive with my FPGA over a Modbus

[GerdW]

Hi Michael,

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@Michael_Smith wrote:
I'm planning to interface Servo Drive with my FPGA over a Modbus

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Ok.

• Which FPGA?
• Which kind of Modbus connection (LAN, RS485)?
• How should your FPGA connect to that Modbus connection?
• Why do you even want to do that in the FPGA?

[Michael_Smith]

@GerdW wrote:

Hi Michael,

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@Michael_Smith wrote:
I'm planning to interface Servo Drive with my FPGA over a Modbus

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Ok.

• Which FPGA?
• Which kind of Modbus connection (LAN, RS485)?
• How should your FPGA connect to that Modbus connection?
• Why do you even want to do that in the FPGA?

Dear,

• myRIO
• RS485
• USB to Serial Connector
• Because I've to rotate a something which is time critical and requires accuracy aswell