# Problem with Addressing Modbus TCP **URL:** \ **Category:** Ignition\ **Tags:** ignition81\ **Created:** [February 13, 2024, 5:53pm UTC](https://forum.inductiveautomation.com/t/problem-with-addressing-modbus-tcp/85646 "2024-02-13T17:53:00Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Miguel\_Gomez](https://avatars.discourse-cdn.com/v4/letter/m/f0a364/32.png) [@Miguel\_Gomez](https://forum.inductiveautomation.com/u/Miguel_Gomez)\ **Post date:** [February 13, 2024, 5:53pm UTC](https://forum.inductiveautomation.com/t/problem-with-addressing-modbus-tcp/85646/1 "2024-02-13T17:53:00Z")
Hello Everyone I need to see the value of a Tag from a AD PLC Productivity 2000 P2-550 CPU I have this information about the Tag ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/f/6/f67684c9129c81b197450b9237acaed44e22c1ac.png) In Ignition I have this ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/e/a/eab90ce3a3e5645fc82aefbfaf7430e5f285bf19.png) As I understand I have to link 2 words because the tag is 32Bit so I have the Addresses 400001 and 400002. HR put by default the 4 or the 40 (I tried both) and I have to put the values in start and End, Select the Step, I just have one Modbus PLC so Unit ID is 0. I tried with 00001, 0001, 001, 01, 1 but the value is always 0 even if I changed from Productivity suite, ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/e/1/e17bf5d743c12deca3187973f00142ac982fa2bb.png) Do you know what is missing? Thank you ---
**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 13, 2024, 5:55pm UTC](https://forum.inductiveautomation.com/t/problem-with-addressing-modbus-tcp/85646/2 "2024-02-13T17:55:58Z")
Pretty sure my P1000 here in the office only responds as Unit #1. ---
**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 13, 2024, 6:01pm UTC](https://forum.inductiveautomation.com/t/problem-with-addressing-modbus-tcp/85646/3 "2024-02-13T18:01:35Z")
Consider just creating OPC tags in the Designer and manually addressing them. Both now while testing, and for production. The address map feature is no good. Try an OPC Item Path like `[DeviceName]1.HRI1`. ---
**Author:** ![Miguel\_Gomez](https://avatars.discourse-cdn.com/v4/letter/m/f0a364/32.png) [@Miguel\_Gomez](https://forum.inductiveautomation.com/u/Miguel_Gomez)\ **Post date:** [February 13, 2024, 9:56pm UTC](https://forum.inductiveautomation.com/t/problem-with-addressing-modbus-tcp/85646/4 "2024-02-13T21:56:55Z")
Well, Thnak you [pturmel](https://forum.inductiveautomation.com/u/pturmel) and [Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron) I tried both possible solutions with no succeed so, what I did was create a new 16bit tag with address 400001 in the program ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/9/d/9de386802607ae8dc21e122e95c56cfd1bb87ef5.png) Then I created a rung with a copy data block and sent the data from CustomerB to ModuleValue1 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/1/0/104167852dde9620d98d56a13a5a03e6403b9232.png) Configured in ignition ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/a/6/a61eda34b55803429d060a406b46fa987add4ccb.png) And Now I can see it in the Designer 🙂 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/8/0/80dcd340918b88e209381b250ef4ae7e6a1202a2.png) ---
**Author:** ![michael.flagler](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/michael.flagler/32/26272_2.png) [@michael.flagler](https://forum.inductiveautomation.com/u/michael.flagler)\ **Post date:** [February 13, 2024, 11:42pm UTC](https://forum.inductiveautomation.com/t/problem-with-addressing-modbus-tcp/85646/5 "2024-02-13T23:42:13Z")
Since the general consensus is that this is no good and shouldn't be used, is it possible to add a big warning banner on that page to warn against using it with maybe a link pointing to the online manual for the proper way of using OPC item paths instead? I feel like it would solve a lot of headaches and confusion. ---
**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 13, 2024, 11:48pm UTC](https://forum.inductiveautomation.com/t/problem-with-addressing-modbus-tcp/85646/6 "2024-02-13T23:48:18Z")
Heh, not sure I could get a buy in for that. It's my strong opinion, not sure about others... and it does work. It's just a huge pain in the ass because: - it introduces an extra layer of indirection that makes troubleshooting difficult (can't look at OPC item path and know what you're reading) - it's restrictive in its expressivity/naming - it's limited to some number of rows based on an unrelated setting about HTTP form sizes - people often mistake this and think they're configuring some sort of list of tags to poll, and then call support asking how to set the rate of the polling group, etc... ---
**Author:** ![Matrix\_Engineering](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/matrix_engineering/32/19781_2.png) [@Matrix\_Engineering](https://forum.inductiveautomation.com/u/Matrix_Engineering)\ **Post date:** [February 13, 2024, 11:56pm UTC](https://forum.inductiveautomation.com/t/problem-with-addressing-modbus-tcp/85646/7 "2024-02-13T23:56:04Z")
I know you got this solved but if you do want to move away from the address mapping, here is a P1-550 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/1/7/1782254cb5241aec2f83bc067d3b867dbf50d78a.png) ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/4/c/4cb6f4c3d8ac1009f3a56bb0b45802d14035fdc6.png) ---
**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 14, 2024, 12:14am UTC](https://forum.inductiveautomation.com/t/problem-with-addressing-modbus-tcp/85646/8 "2024-02-14T00:14:19Z")
> [@Kevin.Herron](#): > > It's my strong opinion, not sure about others Mine too. Strong enough to leave it entirely out of my alternate driver. ---
**Author:** ![Miguel\_Gomez](https://avatars.discourse-cdn.com/v4/letter/m/f0a364/32.png) [@Miguel\_Gomez](https://forum.inductiveautomation.com/u/Miguel_Gomez)\ **Post date:** [February 15, 2024, 4:23pm UTC](https://forum.inductiveautomation.com/t/problem-with-addressing-modbus-tcp/85646/9 "2024-02-15T16:23:22Z")
Hi, yes, I noticed all of that so I tried yesterday how to figure out without the address mapping and finally I understood all that all of you were saying me. ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/9/4/94727ad62e2f8bdea74291fe8054f72eb43a3adf.png) It worked with this mode and the other booleans tags worked with this ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/e/6/e62681f0f947a4408a13f482b0be8a99cd1c8c08.png) Now my tag list is more organized and working. Thank you, all of this is new for me.