# read 2 spaces with node-red-contrib-modbustcp

**URL:** <https://discourse.nodered.org/t/read-2-spaces-with-node-red-contrib-modbustcp/74421>\
**Category:** General\
**Created:** [30 January 2023 13:25 UTC](https://discourse.nodered.org/t/read-2-spaces-with-node-red-contrib-modbustcp/74421 "2023-01-30T13:25:24Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Ersthelfer](https://avatars.discourse-cdn.com/v4/letter/e/48db29/32.png) [@Ersthelfer](https://discourse.nodered.org/u/Ersthelfer)\
**Post date:** [30 January 2023 13:25 UTC](https://discourse.nodered.org/t/read-2-spaces-with-node-red-contrib-modbustcp/74421/1 "2023-01-30T13:25:24Z")

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Hi, I use your "node-red-contrib-modbustcp".

I want to read 2 spaces of my modbustcp pv converter

I want to get the register 5002 to 5036 and it works well.

But I can not read the registers 12999 to 13077 at the same time ☹

If I try to read 5002 to 13077 it look like the Array is to big. So I think i have to read it in 2 blocks.

In the doc I read I can use:

[  
{  
"name": "Reg1",  
"address": 4999,  
"quantity": 72,  
"dataType": "FC4",  
"intervall": 15000,  
"ieeeBE": true,  
"ieeeType": "off"  
},  
{  
"name": "Reg2",  
"address": 12999,  
"quantity": 78,  
"dataType": "FC4",  
"intervall": 15000,  
"ieeeBE": true,  
"ieeeType": "off"  
}  
]

but it doesn't work.

Please can you help me?

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<div class="post-metadata">

**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:** [30 January 2023 15:08 UTC](https://discourse.nodered.org/t/read-2-spaces-with-node-red-contrib-modbustcp/74421/2 "2023-01-30T15:08:57Z")

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> [@Ersthelfer](#):
>
> If I try to read 5002 to 13077 it look like the Array is to big

It is not possible to read more than 125 items in a modbus request due to the specification design. You will have to read these in two separate goes. I would recommend you do not poll at the same time but sequence them one after another.

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<div class="post-metadata">

**Author:** ![Ersthelfer](https://avatars.discourse-cdn.com/v4/letter/e/48db29/32.png) [@Ersthelfer](https://discourse.nodered.org/u/Ersthelfer)\
**Post date:** [30 January 2023 16:14 UTC](https://discourse.nodered.org/t/read-2-spaces-with-node-red-contrib-modbustcp/74421/3 "2023-01-30T16:14:29Z")

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Thanks for answer.

but how I have to do this?

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<div class="post-metadata">

**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:** [30 January 2023 17:03 UTC](https://discourse.nodered.org/t/read-2-spaces-with-node-red-contrib-modbustcp/74421/4 "2023-01-30T17:03:29Z")

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> [@Ersthelfer](#):
>
> but how I have to do this?

wire things in series

e.g: [Modbus Serial - Whole bus disconnects when one device drops - #16 by Steve-Mcl](https://discourse.nodered.org/t/modbus-serial-whole-bus-disconnects-when-one-device-drops/48555/16)

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<div class="post-metadata">

**Author:** ![Ersthelfer](https://avatars.discourse-cdn.com/v4/letter/e/48db29/32.png) [@Ersthelfer](https://discourse.nodered.org/u/Ersthelfer)\
**Post date:** [31 January 2023 06:31 UTC](https://discourse.nodered.org/t/read-2-spaces-with-node-red-contrib-modbustcp/74421/5 "2023-01-31T06:31:09Z")

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Hi,

I use this ModBus Node [https://flows.nodered.org/node/node-red-contrib-modbustcp](https://flows.nodered.org/node/node-red-contrib-modbustcp)

If I use there a 2. instance of the node the communication get fail.

The documentation say, I have to use a "multiple input"

```auto
[
    {
        "name": "Reg1",
        "address": 4999,
        "quantity": 72,
        "dataType": "FC4",
        "intervall": 15000,
        "ieeeBE": true,
        "ieeeType": "off"
    },
    {
        "name": "Reg2",
        "address": 12999,
        "quantity": 78,
        "dataType": "FC4",
        "intervall": 15000,
        "ieeeBE": true,
        "ieeeType": "off"
    }
]

```

But if I connect a inject node to the Modbus node I get a thousand messages per second.  
I am a newbie in node red.  
Can someone please explain to me how I pass the "multiple input" correctly to the Modbus node?

It looks like I am not allowed to upload attachments yet. That's why I save my flow here:

[my ModBus flow](http://www.engel-city.de/webspace/ModBus_Flow.json)

Thanks a lot

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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:** [1 April 2023 06:31 UTC](https://discourse.nodered.org/t/read-2-spaces-with-node-red-contrib-modbustcp/74421/6 "2023-04-01T06:31:26Z")

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