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glavanov

S7-300 data block addressing

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Hello people, i have a task in which i have to read values from S7-300 Data Block

via Mitsubishi HMI (S7-300/400 OP communication driver via CP343-1).

I don't have much experience with S7 data blocks and i need someone to 

confirm if my addresses in the HMI are entered correctly while waiting for the hardware.

In other words i need to know if the DB address offsets are coresponding to Word numbers in the HMI.

I need to know if i'm undertandig right the Address offset after the array structure...

Link to Mitsubishi section Topic with detailed HMI addressing format: https://forums.mrplc.com/index.php?/topic/41888-s7-300-to-got-simple/

Thank you in advance.

Got_Addressing.thumb.jpg.26451038fedac0f

Edited by glavanov
explanation

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That looks right, but I would have to test it to be sure. The first 3 are straightforward. I think you're right that the first ID_Number will be DB1102.DBD28. Be also aware that the Siemens processors arrange the bytes inside the word in reverse order:
SiemensDoubleWord.JPG.9a62ade9ba4581b714

You may have to enable "byte swapping" in the HMI for it to display data correctly.

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Yes, you are right. i know that from a previous project.

i don't think Mitsu HMIs have byte swap option but it's ok.

I am dealing with it easly...

Notation_Method.jpg.50cbe07188f5844c18b1 

If anyone is interested Section 14.4 from here: https://www.allied-automation.com/wp-content/uploads/2015/02/MITSUBISHI_GOT2000-Connection-Manual-Non-Mitsubishi-Product-2-For-GT-Works3.pdf

This only applies to Bit Reading

When INT, DINT and REAL it is streight forward.

Also from previous project i i know that from addres +0.0 to +12.0 it will work fine.

I was worried for the offset after +16.0 array... there is 29 more arrays like it in this DB i have to skip and it will be a mess if i do the offsets wrong...

Thank you Joe E.

Edited by glavanov

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One way to double check yourself is to copy the data from DB1102.DBD28 to an unused MD somewhere and verify the contents are as expected.

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I have all the hardware installed, powered up and communicating with no issue.

The problem is that the datablock is not updating any values, because a specific function of the machine is not allowed at this stage.

I'm working on an in-house built machine extension based on Mitsubishi platform.
I expect authorized personnel from the manufacturer to check and authorize this program function.
I try to be as prepared as possible when this happens, so as not to waste valuable time.

There's no way to simulate.

The only i can think of... can try and write insted of read to specific DB address and lucky enough if DB is not write restricted on my side.

I'm able to monitor the DB via SImatic manager. ...I'll try this.

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You can open a monitor/modify window and write directly to the DB...as long as it isn't being overwritten elsewhere. Another option is to create your own DB that mimics the structure of theirs and confirm the address offsets there.

I just wrote that and realized that I assumed you're using Simatic Manager. If you're using TIA Portal, the monitor/modify function is probably different. I no longer have access to the software to look for it. You should still be able to create your own DB in the PLC, though. Unless the OEM locked down the PLC completely. If they did that...it's more complicated. Do you have a spare PLC to test stuff with? If not, you guys probably should get one one, especially with component lead times what they are right now.

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Yes i'm using Simatic manager and i have a coppy for the S7-300 program but off cource it's locked by the OEM.

But still... i have access to all inputs and can monitor/modify all Q and M that are not used by the sequence program (tested with the Mitsu HMI).

I can't find reason not be able to modify not used variables also... I'll test it first thing in Monday.

Thak you again Joe E.

 

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I understand things a little from the OEM perspective, but it's still annoying when they lock you out of your machine. I'd try it with a spare PLC or, if you have another machine with an S7 in it that isn't locked, try that one. You can add a DB to the PLC without affecting operation at all.

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Confirmed. 

The address offsets are correct as the image in post 1.

I configuged the the numeric displays as numeric inputs in HMI.

When i change values in the HMI all appear correctly in the DB monitored via Simatic manager.

I was not able to modify the DB values in SImatic manager... just monitor.

Case closed. Thanks again.

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Thank you for the followup!

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No need for thanks.
This is the purpose of the forum,
In most cases, it takes a little push in the right direction to get you out of panic mode.
Drinks on me!:kewl:

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