# Modbus TCP Same address, different value

**URL:** <https://forum.inductiveautomation.com/t/modbus-tcp-same-address-different-value/32150>\
**Category:** Ignition\
**Tags:** ignition80, perspective\
**Created:** [February 11, 2020, 10:38pm UTC](https://forum.inductiveautomation.com/t/modbus-tcp-same-address-different-value/32150 "2020-02-11T22:38:15Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![julian.medina](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/julian.medina/32/9805_2.png) [@julian.medina](https://forum.inductiveautomation.com/u/julian.medina)\
**Post date:** [February 11, 2020, 10:38pm UTC](https://forum.inductiveautomation.com/t/modbus-tcp-same-address-different-value/32150/1 "2020-02-11T22:38:15Z")

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Hi!  
So, I have connected ignition to a Power Meter module via Modbus TCP, however I’m having an issue when I use “Bulk” (or group) addressing.

Here, you can see that I have a group called “Corrientes” and a single tag called Ib (current phase 2):

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/2X/9/9b0ae5b62da5786000e39d71d89328354f7747c4.png)

From the addresses, I assume that both Corriente\_1 and Ib are referencing the same address (1101), however I’m getting a wrong value when referencing it within the group:

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/2X/c/c124c94120179b43527b56e636c2554c1c33c094.png)

Any Ideas why could this be happening?  
This difference was noticed while using Quick Client before registering the tags. I still registered the tags to see the differences in real time.

I’m using 0 based registry (no Idea it is correct since the PM manual doesn’t say so) and Ignition 8.0.5.

Thanks in advance, guys!

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**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\
**Post date:** [February 11, 2020, 11:04pm UTC](https://forum.inductiveautomation.com/t/modbus-tcp-same-address-different-value/32150/2 "2020-02-11T23:04:17Z")

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Why do you think they are the same tag?

Corrientes0 is 2 registers, 1100 and 1101.  
Corrientes1 is 2 registers, 1102 and 1103.

Ib is 2 registers, 1101 and 1102.

You’re using a 32-bit type so each tag requires 2 registers.

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**Author:** ![julian.medina](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/julian.medina/32/9805_2.png) [@julian.medina](https://forum.inductiveautomation.com/u/julian.medina)\
**Post date:** [February 11, 2020, 11:07pm UTC](https://forum.inductiveautomation.com/t/modbus-tcp-same-address-different-value/32150/3 "2020-02-11T23:07:42Z")

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Well, according to this manual (and the range used), I assumed it was a double Integer

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/2X/6/6be5e235295d22a6a0bea8e43e942f6918af4918.png)

Hold on, how many bytes does a register have?🤔

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<div class="post-metadata">

**Author:** ![julian.medina](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/julian.medina/32/9805_2.png) [@julian.medina](https://forum.inductiveautomation.com/u/julian.medina)\
**Post date:** [February 11, 2020, 11:15pm UTC](https://forum.inductiveautomation.com/t/modbus-tcp-same-address-different-value/32150/4 "2020-02-11T23:15:42Z")

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Well, either way, Switching to UInt16 did the trick, now I have my proper values.

Thanks a lot Kevin!

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<div class="post-metadata">

**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\
**Post date:** [February 11, 2020, 11:18pm UTC](https://forum.inductiveautomation.com/t/modbus-tcp-same-address-different-value/32150/5 "2020-02-11T23:18:08Z")

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Modbus registers are 16-bit (2 bytes).

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<div class="post-metadata">

**Author:** ![julian.medina](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/julian.medina/32/9805_2.png) [@julian.medina](https://forum.inductiveautomation.com/u/julian.medina)\
**Post date:** [February 12, 2020, 2:56pm UTC](https://forum.inductiveautomation.com/t/modbus-tcp-same-address-different-value/32150/6 "2020-02-12T14:56:43Z")

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That’s why!

Thanks a lot!