# Direct readout S7300 PLC-variable table

**URL:** <https://discourse.nodered.org/t/direct-readout-s7300-plc-variable-table/23550>\
**Category:** Industrial\
**Created:** [24 March 2020 08:45 UTC](https://discourse.nodered.org/t/direct-readout-s7300-plc-variable-table/23550 "2020-03-24T08:45:11Z")\
**Posts on this page:** 10\
**Page:** 1

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**Author:** ![spranz](https://avatars.discourse-cdn.com/v4/letter/s/f04885/32.png) [@spranz](https://discourse.nodered.org/u/spranz)\
**Post date:** [24 March 2020 08:45 UTC](https://discourse.nodered.org/t/direct-readout-s7300-plc-variable-table/23550/1 "2020-03-24T08:45:11Z")

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Hello,  
i start my first project with node red.  
I already readout with "plcindustry" the values from a DB in the PLC.  
But now i fail to readout the same variable direct from the variable-table.  
What is wrong with my node? Or do i have to convert it ? (and how?)  
In the picture you see the same variable (one from DB 0.xxx witch is correct) (and the same direct from the variable table with a wrong value)  
I hope you understand what i mean. (sorry my englisch is not so good 😉

Best regards  
Manuel

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/3/8/385a3a069aa6e7f5d1f309cae05d7d4e765bdad1.png)

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**Author:** ![rromele](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/rromele/32/18431_2.png) [@rromele](https://discourse.nodered.org/u/rromele)\
**Post date:** [24 March 2020 20:17 UTC](https://discourse.nodered.org/t/direct-readout-s7300-plc-variable-table/23550/2 "2020-03-24T20:17:00Z")

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Hi,  
sorry for the question, it makes me curious, why do you want to read the VAT tables with node-red?  
VAT are normally used for internal debugging, for data transfer DBs are used as you have already done correctly.  
🤔 🤔

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**Author:** ![spranz](https://avatars.discourse-cdn.com/v4/letter/s/f04885/32.png) [@spranz](https://discourse.nodered.org/u/spranz)\
**Post date:** [30 March 2020 08:17 UTC](https://discourse.nodered.org/t/direct-readout-s7300-plc-variable-table/23550/3 "2020-03-30T08:17:45Z")

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Hi,  
the problem is, that i have some mashines where the vat has the value i want to readout, but in the plc prog it is not used in a DB.  
And i don´t want to change all plc programms on the existing mashines.  
So it would be the easyerst way to direct readout the vat.

BR

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**Author:** ![VP2020](https://avatars.discourse-cdn.com/v4/letter/v/e95f7d/32.png) [@VP2020](https://discourse.nodered.org/u/VP2020)\
**Post date:** [30 March 2020 10:25 UTC](https://discourse.nodered.org/t/direct-readout-s7300-plc-variable-table/23550/4 "2020-03-30T10:25:37Z")

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in VAT you will get assigned absolute addresses ...VAT is virtual so you can not directly readout VAT .but addresses you can read which will be DB,MB or any other peripheral Address.

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**Author:** ![cigno](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/cigno/32/91812_2.png) [@cigno](https://discourse.nodered.org/u/cigno)\
**Post date:** [30 March 2020 15:14 UTC](https://discourse.nodered.org/t/direct-readout-s7300-plc-variable-table/23550/5 "2020-03-30T15:14:10Z")

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hello a question.  
what library do you use for the 300 series plc,  
because I have S7 1200 and I don't use any library.  
but for the 300 you need a library?  
thanks

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**Author:** ![rromele](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/rromele/32/18431_2.png) [@rromele](https://discourse.nodered.org/u/rromele)\
**Post date:** [30 March 2020 20:45 UTC](https://discourse.nodered.org/t/direct-readout-s7300-plc-variable-table/23550/6 "2020-03-30T20:45:41Z")

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Hi,  
sorry if I insist but VAT always point to plc memory areas, so if you have access to the cpu you are able to know where to direct node-red without having to modify the software of your machines.

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**Author:** ![rromele](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/rromele/32/18431_2.png) [@rromele](https://discourse.nodered.org/u/rromele)\
**Post date:** [30 March 2020 20:50 UTC](https://discourse.nodered.org/t/direct-readout-s7300-plc-variable-table/23550/7 "2020-03-30T20:50:42Z")

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Hi,  
node-red-contrib-s7-comm

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**Author:** ![cigno](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/cigno/32/91812_2.png) [@cigno](https://discourse.nodered.org/u/cigno)\
**Post date:** [1 April 2020 07:27 UTC](https://discourse.nodered.org/t/direct-readout-s7300-plc-variable-table/23550/8 "2020-04-01T07:27:57Z")

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ok thank you very much for your answer.

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**Author:** ![spranz](https://avatars.discourse-cdn.com/v4/letter/s/f04885/32.png) [@spranz](https://discourse.nodered.org/u/spranz)\
**Post date:** [1 April 2020 13:46 UTC](https://discourse.nodered.org/t/direct-readout-s7300-plc-variable-table/23550/9 "2020-04-01T13:46:09Z")

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Ok, thank you very much for your help. Then i will look how i can readout the values another way...

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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:** [31 May 2020 13:49 UTC](https://discourse.nodered.org/t/direct-readout-s7300-plc-variable-table/23550/10 "2020-05-31T13:49:46Z")

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