# S7Comm node Output operation

**URL:** <https://discourse.nodered.org/t/s7comm-node-output-operation/61164>\
**Category:** Industrial\
**Created:** [12 April 2022 10:52 UTC](https://discourse.nodered.org/t/s7comm-node-output-operation/61164 "2022-04-12T10:52:29Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![DSongra11\_forum.com](https://avatars.discourse-cdn.com/v4/letter/d/f04885/32.png) [@DSongra11\_forum.com](https://discourse.nodered.org/u/DSongra11_forum.com)\
**Post date:** [12 April 2022 10:52 UTC](https://discourse.nodered.org/t/s7comm-node-output-operation/61164/1 "2022-04-12T10:52:29Z")

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Hello,

I am taking data from Siemens PLC into node-red using the S7comm node.

Reading operation performs perfectly, but not able to write getting error as you can in the screenshot.

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/7/5/75bbc4953a32ff018855fbe2d3f14eb2dfe91a65.png)

Yellow highlight - For Read Operation  
Red Highlight - For Write Operation

Br,  
Devendra Songra

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<div class="post-metadata">

**Author:** ![Cristiano](https://avatars.discourse-cdn.com/v4/letter/c/b5e925/32.png) [@Cristiano](https://discourse.nodered.org/u/Cristiano)\
**Post date:** [13 April 2022 22:49 UTC](https://discourse.nodered.org/t/s7comm-node-output-operation/61164/2 "2022-04-13T22:49:09Z")

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Hello

Can u share more details? what are trying to write? boolean ? db ?

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<div class="post-metadata">

**Author:** ![DSongra11\_forum.com](https://avatars.discourse-cdn.com/v4/letter/d/f04885/32.png) [@DSongra11\_forum.com](https://discourse.nodered.org/u/DSongra11_forum.com)\
**Post date:** [14 April 2022 04:04 UTC](https://discourse.nodered.org/t/s7comm-node-output-operation/61164/3 "2022-04-14T04:04:00Z")

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Hello,

I am trying to write Boolean data for output.

Br,  
Devendra

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<div class="post-metadata">

**Author:** ![DSongra11\_forum.com](https://avatars.discourse-cdn.com/v4/letter/d/f04885/32.png) [@DSongra11\_forum.com](https://discourse.nodered.org/u/DSongra11_forum.com)\
**Post date:** [14 April 2022 05:51 UTC](https://discourse.nodered.org/t/s7comm-node-output-operation/61164/4 "2022-04-14T05:51:41Z")

</div>

Hello,

As below error, I am getting while trying to perform a write operation.

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/f/7/f7f31d83b29500f6e134595065f87c4b16dc2ae7.png)

Please find node red flow

```auto
[{"id":"fc79ac05.92266","type":"inject","z":"9fae712c.a0866","name":"","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"true","payloadType":"bool","x":110,"y":94,"wires":[["ba050d00.316df"]]},{"id":"ba050d00.316df","type":"s7comm write","z":"9fae712c.a0866","connection":"22bb055a.e4e8fa","payload":"{\"S7_Type\":\"Q\",\"S7_DBnum\":\"0\",\"S7_Datatype\":\"X\",\"S7_Offset\":\"33\",\"S7_BitOffset\":\"1\",\"S7_Quantity\":\"1\",\"S7_Name\":\"Out\"}","s7Name":"Out","topic":"","name":"","signalSetted":false,"x":360,"y":94,"wires":[["dc07eade.836518"]]},{"id":"dc07eade.836518","type":"debug","z":"9fae712c.a0866","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload.value","targetType":"msg","statusVal":"","statusType":"auto","x":670,"y":94,"wires":[]},{"id":"22bb055a.e4e8fa","type":"s7comm","ip":"192.168.2.1","port":"102","rack":"0","slot":"2","payload":[{"S7_Type":"Q","S7_DBnum":"0","S7_Datatype":"X","S7_Offset":"33","S7_BitOffset":"1","S7_Quantity":"1","S7_Name":"Out"},{"S7_Type":"I","S7_DBnum":"0","S7_Datatype":"B","S7_Offset":"34","S7_BitOffset":"1","S7_Quantity":"1","S7_Name":"In"}]}]

```

Br,  
Devendra Songra

_Admin edit, use correct formatting for forum_

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<div class="post-metadata">

**Author:** ![MountainKing91](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/mountainking91/32/59516_2.png) [@MountainKing91](https://discourse.nodered.org/u/MountainKing91)\
**Post date:** [16 April 2022 18:35 UTC](https://discourse.nodered.org/t/s7comm-node-output-operation/61164/5 "2022-04-16T18:35:42Z")

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Can you copy the flow again? There is some error apparently.

Anyway, from the documentation it looks like the payload you want to write must be formatted in a precise way; take a look here:

> <https://github.com/Hilscher/node-red-contrib-s7comm/blob/master/USAGE.md>

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<div class="post-metadata">

**Author:** ![DSongra11\_forum.com](https://avatars.discourse-cdn.com/v4/letter/d/f04885/32.png) [@DSongra11\_forum.com](https://discourse.nodered.org/u/DSongra11_forum.com)\
**Post date:** [18 April 2022 04:48 UTC](https://discourse.nodered.org/t/s7comm-node-output-operation/61164/6 "2022-04-18T04:48:07Z")

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Thanks, MountainKing91 for your support, issue is resolved.

For Writing, I have used the below formats in inject node and the issue is resolved.

for boolean value: {"value":[true]}  
for single value: {"value":[1]}  
for array value: {"value":[1,2,3]}  
for Character value:{"value":["S"]}  
for string value:{"value":["Simatic"]}

Br,  
Devendra

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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:** [2 May 2022 04:48 UTC](https://discourse.nodered.org/t/s7comm-node-output-operation/61164/7 "2022-05-02T04:48:41Z")

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