Citect V7.2 ABCLX Write to STRING Tag

[rvankoppen]

Hello,

I am using CITECT V7.2 with the ABCLX driver to communicate to a compactlogix L30ER.

I want to make a simple string tag that I can key into from a display in CITECT and have the value write to the PLC string tag.

So far from the ABCLX help manual they are looking for this kind of structure.

{
DINT LEN
SINT[ ] DATA
}

To me this looks like I should format my string tag address (in CITECT variable tags) as:

Mytag{ 10 SINT[ ] DATA }
OR maybe
Mytag{ 10 LEN SINT[0] DATA}
OR maybe
Mytag{ 10 SINT[0] DATA}

There are many different possibilities.

All of what I've tried so far return a BAD value in citect. I am using 10 for length as a general number for now as the strings are intended to have a max of 10 characters.

If I use Mytag without any other extra fluff on the tag then I can read from the plc without issue, but I would like to write to the tag.

What they don't do is show a good example of a string tag after showing the structure like they do with all the other tags with array and UDT types in the help manual.

Has any ever successfully written to a logix type PLC string tag from CITECT before?

 

[drbitboy]

Rather than trying to clone Our Leader directly into his suit by fiddling around with DINTs and a string in a structure in citect, I would move the 10-character string into the last three DINTs of a four-DINT array, and transfer that, then COP those four DINTs in the CLX into a string. (I assume the CLX string is a DINT length followed by SINTs with the characters).

You might need to play with the byte order a bit, but if all of the characters are 7-bit ASCII (space 20h through tilde 7Eh), then there is a simple arthmetic conversion from each 4-character sub-string to its corresponding DINT in the array.

That said, this may be more work than it's worth, and your current approach just needs to find the correct syntax, which someone who has already done it will provide.

 

[rvankoppen]

drbitboy thank you for the reply, that may be my best and only option.

Now I just have to copy some Cicode to get it done.

 

[andrewf]

That help section that you are referencing is for Arrays, even though I'm fairly sure it's incorrect for Arrays anyway.

Just set your "Mytag" as data type STRING in Citect. If it is displaying OK then use TagWrite() function to modify to a new value.

If you don't need this String value in the PLC you can setup the tag as a memory tag or local variable.

If you have issues reply with the ABCLX driver version and also service pack (if any) of your Citect 7.2 install.

 

[rvankoppen]

AndrewF

So we tried the TagWrite() function tied to a button and put the tags we want to monitor on the same display, still not able to write to the PLC String. The value changes for a very brief time then it changes back to what the PLC value of the string is (which is just blank right now).

For some reason the PLC will not let Citect write to it's string tags, I have confirmed that the tag has read/ write access in the PLC.

The ABCLX Driver is v3.04.16.000 product version 5.50.

Citect is Version 7.3 and not 7.2 that is a typo on my part.

Thanks for the help so far.

 

[andrewf]

I' assuming you are running the project on a single machine with no clients, so you are testing this on the machine that is the I/O server.

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