# I have a basic question about the S7

**URL:** <https://discourse.nodered.org/t/i-have-a-basic-question-about-the-s7/88529>\
**Category:** General\
**Created:** [6 June 2024 06:21 UTC](https://discourse.nodered.org/t/i-have-a-basic-question-about-the-s7/88529 "2024-06-06T06:21:35Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![Xiang](https://avatars.discourse-cdn.com/v4/letter/x/9fc348/32.png) [@Xiang](https://discourse.nodered.org/u/Xiang)\
**Post date:** [6 June 2024 06:21 UTC](https://discourse.nodered.org/t/i-have-a-basic-question-about-the-s7/88529/1 "2024-06-06T06:21:35Z")

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I used the `s7 in` to connect the PLC and read the data in it.But I have a trouble.

 ![32f0c869dd58b0b092293886cd0bddee](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/2/d/2d7ec93aa500300e39d85b0eb190bda8361f37b5.png)The address of one of the data is `DB407,D78.1` in PLC.I don't know how to convert it to an address in `s7 in` so that I can read this data.

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**Author:** ![Xiang](https://avatars.discourse-cdn.com/v4/letter/x/9fc348/32.png) [@Xiang](https://discourse.nodered.org/u/Xiang)\
**Post date:** [6 June 2024 06:22 UTC](https://discourse.nodered.org/t/i-have-a-basic-question-about-the-s7/88529/2 "2024-06-06T06:22:52Z")

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I checked the official document, which does not say how to convert `D78.1`.

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**Author:** ![KarolisL](https://avatars.discourse-cdn.com/v4/letter/k/a4c791/32.png) [@KarolisL](https://discourse.nodered.org/u/KarolisL)\
**Post date:** [6 June 2024 19:36 UTC](https://discourse.nodered.org/t/i-have-a-basic-question-about-the-s7/88529/3 "2024-06-06T19:36:23Z")

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Try DB407,X78.1..

booleans are only variables that contain"." in their addressing (unless you use strings) then

DB407,S78.1

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**Author:** ![Xiang](https://avatars.discourse-cdn.com/v4/letter/x/9fc348/32.png) [@Xiang](https://discourse.nodered.org/u/Xiang)\
**Post date:** [7 June 2024 03:34 UTC](https://discourse.nodered.org/t/i-have-a-basic-question-about-the-s7/88529/4 "2024-06-07T03:34:42Z")

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But it is a binary variables not boolean.

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**Author:** ![KarolisL](https://avatars.discourse-cdn.com/v4/letter/k/a4c791/32.png) [@KarolisL](https://discourse.nodered.org/u/KarolisL)\
**Post date:** [7 June 2024 05:33 UTC](https://discourse.nodered.org/t/i-have-a-basic-question-about-the-s7/88529/5 "2024-06-07T05:33:14Z")

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What do you mean by binary? Binary is representation of number:  
10 -decimal  
2#1010 - binary  
16#A - hex

show screenshot of your DB407, area 78. If your variables are numbers - go for numbers, if they are boolean (true/false) try DB407,X78.1

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<div class="post-metadata">

**Author:** ![Xiang](https://avatars.discourse-cdn.com/v4/letter/x/9fc348/32.png) [@Xiang](https://discourse.nodered.org/u/Xiang)\
**Post date:** [7 June 2024 06:43 UTC](https://discourse.nodered.org/t/i-have-a-basic-question-about-the-s7/88529/6 "2024-06-07T06:43:34Z")

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I use `word` directly.`DB407,WORD78.1` can get the number what I want.Thank you very much.

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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 June 2024 06:44 UTC](https://discourse.nodered.org/t/i-have-a-basic-question-about-the-s7/88529/7 "2024-06-21T06:44:23Z")

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