# Modbus help to read messages

**URL:** <https://discourse.nodered.org/t/modbus-help-to-read-messages/51282>\
**Category:** General\
**Created:** [20 September 2021 11:05 UTC](https://discourse.nodered.org/t/modbus-help-to-read-messages/51282 "2021-09-20T11:05:02Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![denissanga](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/denissanga/32/48346_2.png) [@denissanga](https://discourse.nodered.org/u/denissanga)\
**Post date:** [20 September 2021 11:05 UTC](https://discourse.nodered.org/t/modbus-help-to-read-messages/51282/1 "2021-09-20T11:05:02Z")

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Hi all, I'm new in modbus protocol communication and I would ask few questions.

I have a slave and an excel with a table of registers, quantities and description and I would understant how to receive the data in correct format from slave. I can connect to the slave until now and I receive datas but I have many difficulties to undestand the meaning of messages.

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/a/b/abce99534c017498978c05239c7b8f8fecd9e7c6.png)

For example for the registers with dimension 1 I use the following code:

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/e/a/eaf3b9c0f5956da08fbc65844de900afdcbf29a8.png)  
with function:

> msg.payload = {  
> 'fc': 3,  
> 'unitid': 1,  
> 'address': 4,  
> 'quantity': 1  
> }  
> return msg;

and I receive the temperature as integer number and not float number.

then I would ask how to receive registers with quantities 2 or more and composed by msl and lsb words.  
Can some one help me to undestant how to read correctly the different addresses with dimension 1 or more and composed by msl and lsb words?  
many thanks in advance

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [19 November 2021 11:05 UTC](https://discourse.nodered.org/t/modbus-help-to-read-messages/51282/2 "2021-11-19T11:05:12Z")

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