# Interlock multiple Modbus TCP Read operation to same server

**URL:** <https://discourse.nodered.org/t/interlock-multiple-modbus-tcp-read-operation-to-same-server/47459>\
**Category:** General\
**Created:** [22 June 2021 06:34 UTC](https://discourse.nodered.org/t/interlock-multiple-modbus-tcp-read-operation-to-same-server/47459 "2021-06-22T06:34:42Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![jumpier](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/jumpier/32/44058_2.png) [@jumpier](https://discourse.nodered.org/u/jumpier)\
**Post date:** [22 June 2021 06:34 UTC](https://discourse.nodered.org/t/interlock-multiple-modbus-tcp-read-operation-to-same-server/47459/1 "2021-06-22T06:34:42Z")

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Hy,

i need to request many data from a single device, using Modbus TCP read; the device is used as a gateway ti other 6 slave with differente Modbus ID (e.g. 192.168.120.100 ID = 1 to device 01, 192.168.10.100 ID = 2 to device 2 and so on ...).  
Now, i've import the library "node-red-contrib-modbus" v5.14.0.  
I'm currently used the Modbus Read function with poll rate equal to 2 second. Each Read function is call on a different flow.

My question: is possible interlock the 6 Modbus Read nodes?  
Is possible start Modbus Read 1; when done, start Modbus Read 2 and so on for the 6 nodes?

Thanks for any suggestions.

Have a nice day, Jumpier

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**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [22 June 2021 07:24 UTC](https://discourse.nodered.org/t/interlock-multiple-modbus-tcp-read-operation-to-same-server/47459/2 "2021-06-22T07:24:41Z")

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> [@jumpier](#):
>
> My question: is possible interlock the 6 Modbus Read nodes?  
> Is possible start Modbus Read 1; when done, start Modbus Read 2 and so on for the 6 nodes?

Wire them in series.

modbus1 ---\> change node (store data in msg.data1) --\> modbus2 ---\> change node (store data in msg.data2) --\> modbus3 ---\> change node (store data in msg.data3) --\> etc etc

At the end you will have results in `msg.data1` `msg.data2` `msg.data2` etc.

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**Author:** ![jumpier](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/jumpier/32/44058_2.png) [@jumpier](https://discourse.nodered.org/u/jumpier)\
**Post date:** [22 June 2021 07:46 UTC](https://discourse.nodered.org/t/interlock-multiple-modbus-tcp-read-operation-to-same-server/47459/3 "2021-06-22T07:46:41Z")

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Good morning Steve,

thanks for your reply; i'm new by with Node-RED. I'm so sorry but i don't understnad your suggestion.

Can you explain me with a sample?

Thanks

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**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [22 June 2021 07:51 UTC](https://discourse.nodered.org/t/interlock-multiple-modbus-tcp-read-operation-to-same-server/47459/4 "2021-06-22T07:51:00Z")

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Pretty much as I said...

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/6/a/6ae21c64dff8a900b4315e2bef4c18a4bffc4926.png)

wiring in series will cause the operations to occur serially (which you asked for)

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> [@jumpier](#):
>
> i'm new by with Node-RED

As a new user, I recommend watching this playlist: [Node-RED Essentials](https://www.youtube.com/playlist?list=PLyNBB9VCLmo1hyO-4fIZ08gqFcXBkHy-6). The videos are done by the developers of node-red. They're nice & short and to the point. You will understand a whole lot more in about 1 hour. A small investment for a lot of gain.

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**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [21 August 2021 07:51 UTC](https://discourse.nodered.org/t/interlock-multiple-modbus-tcp-read-operation-to-same-server/47459/5 "2021-08-21T07:51:46Z")

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