# Siemens S7-300 address mapping

**URL:** <https://forum.inductiveautomation.com/t/siemens-s7-300-address-mapping/25298>\
**Category:** Ignition\
**Created:** [May 24, 2019, 1:42pm UTC](https://forum.inductiveautomation.com/t/siemens-s7-300-address-mapping/25298 "2019-05-24T13:42:42Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![saadia.gauhar](https://avatars.discourse-cdn.com/v4/letter/s/9fc29f/32.png) [@saadia.gauhar](https://forum.inductiveautomation.com/u/saadia.gauhar)\
**Post date:** [May 24, 2019, 1:42pm UTC](https://forum.inductiveautomation.com/t/siemens-s7-300-address-mapping/25298/1 "2019-05-24T13:42:42Z")

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I am trying to map an address from a S7-300 to an opc tag this is what I have from the PLC programmer DB18.DBW6. Can someone please help me create the correct addressing in OPC tag.

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**Author:** ![dano38291](https://avatars.discourse-cdn.com/v4/letter/d/9d8465/32.png) [@dano38291](https://forum.inductiveautomation.com/u/dano38291)\
**Post date:** [May 24, 2019, 2:35pm UTC](https://forum.inductiveautomation.com/t/siemens-s7-300-address-mapping/25298/2 "2019-05-24T14:35:28Z")

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This help file covers it well.  
[https://docs.inductiveautomation.com/display/DOC79/Siemens](https://docs.inductiveautomation.com/display/DOC79/Siemens)

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**Author:** ![saadia.gauhar](https://avatars.discourse-cdn.com/v4/letter/s/9fc29f/32.png) [@saadia.gauhar](https://forum.inductiveautomation.com/u/saadia.gauhar)\
**Post date:** [May 24, 2019, 2:50pm UTC](https://forum.inductiveautomation.com/t/siemens-s7-300-address-mapping/25298/3 "2019-05-24T14:50:24Z")

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I have gone through this several times, but its not helpful in this case. I still don’t understand how to map DB18.DBW6. Probably I am ignorant 😃

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**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [May 24, 2019, 2:55pm UTC](https://forum.inductiveautomation.com/t/siemens-s7-300-address-mapping/25298/4 "2019-05-24T14:55:22Z")

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> [@saadia.gauhar](#):
>
> I still don’t understand how to map DB18.DBW6.

1. You need to tell us the data type you expect in that word for specific help, and
2. Your programmer needs to follow the rules for configuring the PLC as described in "Considerations for 1200 and 1500 Devices" in the linked manual page. If that isn't done, no mapping will work at all.

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**Author:** ![chi](https://avatars.discourse-cdn.com/v4/letter/c/0ea827/32.png) [@chi](https://forum.inductiveautomation.com/u/chi)\
**Post date:** [May 24, 2019, 3:32pm UTC](https://forum.inductiveautomation.com/t/siemens-s7-300-address-mapping/25298/5 "2019-05-24T15:32:48Z")

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If this is an integer value, the address is `[device]DB18,I6` for an unsigned word use `[device]DB18,W6`.