# Modbus with Energiya board

**URL:** <https://mangoh.discourse.group/t/modbus-with-energiya-board/9336>\
**Category:** mangOH Yellow antenna\
**Created:** [June 15, 2021, 11:57am UTC](https://mangoh.discourse.group/t/modbus-with-energiya-board/9336 "2021-06-15T11:57:06Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![lukasmertens](https://avatars.discourse-cdn.com/v4/letter/l/48db29/32.png) [@lukasmertens](https://mangoh.discourse.group/u/lukasmertens)\
**Post date:** [June 15, 2021, 11:57am UTC](https://mangoh.discourse.group/t/modbus-with-energiya-board/9336/1 "2021-06-15T11:57:06Z")

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Hi,  
I’m trying to read modbus from a device which also has a RS485 connector. When i try to install the energiya app there are no error’s. When i look into octave there is no energiya resource:

 ![afbeelding](https://us1.discourse-cdn.com/flex016/uploads/mangoh/original/2X/8/87900221861fb5e4d4e9ffd95ba813a02579073e.png)

When i go into my Mangoh Yellow using putty and run “app status” i see the app "Energiya "  
 ![afbeelding](https://us1.discourse-cdn.com/flex016/uploads/mangoh/original/2X/e/e78cd17ff8b7686d2ff7c00ab427e85e23bacc42.png)

I configured my modbus in the “services” tab.

 ![afbeelding](https://us1.discourse-cdn.com/flex016/uploads/mangoh/original/2X/c/c75e1ad302c7233aa2a5687911f4e81fbf72b5cd.png)

After that wen i’m going to look into my resources. There is no data from the modbus.

 ![afbeelding](https://us1.discourse-cdn.com/flex016/uploads/mangoh/original/2X/6/652e3600af56b35f53df109f13b57cd728c40958.png)

**Where is the problem? And how can i fix it?**  
Thank you in advanced!

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**Author:** ![kalaivani](https://sea2.discourse-cdn.com/flex016/user_avatar/mangoh.discourse.group/kalaivani/32/2183_2.png) [@kalaivani](https://mangoh.discourse.group/u/kalaivani)\
**Post date:** [March 19, 2022, 5:57am UTC](https://mangoh.discourse.group/t/modbus-with-energiya-board/9336/2 "2022-03-19T05:57:00Z")

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hi how to include libmodbus library in legato project, any sample available

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**Author:** ![pankajsant1](https://avatars.discourse-cdn.com/v4/letter/p/c5a1d2/32.png) [@pankajsant1](https://mangoh.discourse.group/u/pankajsant1)\
**Post date:** [March 22, 2022, 1:38am UTC](https://mangoh.discourse.group/t/modbus-with-energiya-board/9336/3 "2022-03-22T01:38:25Z")

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@kalaivani

to include libmodbus you can use the linux source and the modbus recipe in your local.conf

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**Author:** ![kalaivani](https://sea2.discourse-cdn.com/flex016/user_avatar/mangoh.discourse.group/kalaivani/32/2183_2.png) [@kalaivani](https://mangoh.discourse.group/u/kalaivani)\
**Post date:** [March 22, 2022, 10:37am UTC](https://mangoh.discourse.group/t/modbus-with-energiya-board/9336/4 "2022-03-22T10:37:29Z")

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hi included the libmodbus , but getting the following error  
“undefined reference to `modbus_connect'" " undefined reference to `modbus\_new\_rtu’”  
how to rectify the error… Thanks in advance

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<div class="post-metadata">

**Author:** ![kalaivani](https://sea2.discourse-cdn.com/flex016/user_avatar/mangoh.discourse.group/kalaivani/32/2183_2.png) [@kalaivani](https://mangoh.discourse.group/u/kalaivani)\
**Post date:** [March 26, 2022, 7:40am UTC](https://mangoh.discourse.group/t/modbus-with-energiya-board/9336/5 "2022-03-26T07:40:24Z")

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hi any c sample available to read multiple slave from the serial connection using libmodbus function, i would like to know in which slave id which sensor is connected?  
i can able to read when slave id is configured as 1, but when i chanGE THE SLAVE Id as 2 i cant read anything

how to change slave id, what are the steps to be followed to change slave id using lib modbus  
similarly step to be followed to read multiple salve id

tthanks in advance