# Modbus Addressing on ET-7000/PET-7000

**URL:** <https://forum.inductiveautomation.com/t/modbus-addressing-on-et-7000-pet-7000/85960>\
**Category:** Ignition\
**Created:** [February 19, 2024, 5:34pm UTC](https://forum.inductiveautomation.com/t/modbus-addressing-on-et-7000-pet-7000/85960 "2024-02-19T17:34:30Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Efren\_Benitez](https://avatars.discourse-cdn.com/v4/letter/e/e495f1/32.png) [@Efren\_Benitez](https://forum.inductiveautomation.com/u/Efren_Benitez)\
**Post date:** [February 19, 2024, 5:34pm UTC](https://forum.inductiveautomation.com/t/modbus-addressing-on-et-7000-pet-7000/85960/1 "2024-02-19T17:34:30Z")

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I have the addressing for the PET device from the manual, but can’t get the values to show up in Ignition.

Attached is the screen shot of the manual, with the address I am trying to get.  
What do I need to enter in the device configuration?

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/5/f/5fb10198070043175a6267d46d24598fbf04b3ae.png)  
 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/6/a/6a467419104b305a59be648718768f9496fee7ca.png)

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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:** [February 19, 2024, 5:39pm UTC](https://forum.inductiveautomation.com/t/modbus-addressing-on-et-7000-pet-7000/85960/2 "2024-02-19T17:39:55Z")

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First, discard your address map. It is no longer recommended. Just create OPC tags with the appropriate manual addressing.

Since it is obvious that the lowest address is zero, you need to ensure "Zero-based addressing" is turned on in your device's advanced settings (on the Ignition side).

You may also need to determine if unit #0 is actually appropriate. While common for many Modbus TCP devices, unit #1 is also common. (Unit zero is special on Modbus RTU, so definitely not correct if you are using RTU anywhere.)

So, try addresses like `[devName]IR0` or `[devName]1.IR0` as OPC Item Paths to read that first register.

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**Author:** ![Efren\_Benitez](https://avatars.discourse-cdn.com/v4/letter/e/e495f1/32.png) [@Efren\_Benitez](https://forum.inductiveautomation.com/u/Efren_Benitez)\
**Post date:** [February 19, 2024, 6:13pm UTC](https://forum.inductiveautomation.com/t/modbus-addressing-on-et-7000-pet-7000/85960/3 "2024-02-19T18:13:15Z")

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Ive turned on the "Zero-based addressing", changed the addresses in the OPC Item Paths and now its working! Now I just need to scale the value.

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/5/6/56f438ae70679fa0b00cf79d57321f9b939bcb19.png)

Thanks a lot Phil!!