RobD
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Joined: 12 Jun 2021, 09:11

Virtual Modbus Slave and Node-Red

15 Jun 2021, 12:59

Hi, I read a post indicating that nodes for Node-Red where being developed to allow access to the virtual Modbus slave module's registers from Node-Red. I have not been able to find any such nodes and was wondering if this work was ever completed or is there an existing method for communicating with the virtual slave module?

Kind regards,
Rob
 
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dirk
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Joined: 15 Dec 2016, 13:19
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Re: Virtual Modbus Slave and Node-Red

21 Jun 2021, 16:59

Hi Rob, I took the liberty of moving your post here. This is where the experts who developed these nodes moderate.
In general, however, you can always access values from the process image by using an "exec" node.
You can then execute e.g.: "piTest -1 -q -r MyVariable" to get the value of MyVariable.
 
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nicolaiB
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Re: Virtual Modbus Slave and Node-Red

25 Jun 2021, 13:11

Hi Rob,

this should be possible. How does your current configuration (modbus in pictory, nodered) look like?

Nicolai
 
RobD
Topic Author
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Joined: 12 Jun 2021, 09:11

Re: Virtual Modbus Slave and Node-Red

02 Jul 2021, 07:14

Hi Nicolai,

I have opted for using the Modbus Server node from node-red-contrib-modbus instead of the virtual Modbus slave in Pictory. This has been working well so far.
I am currently writing data to about 70 registers and reading about 15 coils and I did not think invoking piTest was a very efficient way to do this.

Regards,
Rob

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