Explain the basics HMI / PLC Tag sharing

[milmat1]

I have experience programming in an environment where the HMI and the PLC are all in a single software environment. Meaning all the tags and variables are shared automatically.
Can someone explain the basic mechanics of using separate HMI and PLC software packages. How do they share tags etc. Do you set up an exchange of some type for every instance where you need to share data ?

I just need an overview of how this works.....

 

[cwal61]

Do you set up an exchange of some type for every instance where you need to share data ?

YES.

Give the Forum Members more detail on products being used for more detailed answers.

 

[osmanmom]

if a driver driving a car he needs to know the car but the car did not need to know the driver.

maybe right maybe wrong, he,he

 

[mk42]

I have experience programming in an environment where the HMI and the PLC are all in a single software environment. Meaning all the tags and variables are shared automatically.
Can someone explain the basic mechanics of using separate HMI and PLC software packages. How do they share tags etc. Do you set up an exchange of some type for every instance where you need to share data ?

I just need an overview of how this works.....

In my experience, you usually do some sort of export function in the PLC software, and then import it into the HMI software. Often times you need a tool to massage the data formats and make it match.

Or, worst case, you have to create every tag manually, which sucks.

 

[Tan_TAD]

Do you mean using the RSlogix and FactoryTalk?
If yes,
1. Connect the computer, PLC and your HMI panel.
2. Configure the connection between PLC and HMI.
3. Create tags in the HMI tags tab. Each tag has to have a data source from the PLC (Factorytalk will see the data source if you configure the connection correctly)
4. Create graphics in the page and assign the tag and address to them.

Hope this help!

 

[milmat1]

I wasn't thinking of a particular brand or combo. just generally speaking. I may do a project here soon using a Automation direct PLC and C-MORE touchscreen.
I'm sure I can figure this out from the manuals, just need an overview of how that works..

 

[Bullzi]

I will take a shot at it:
The PLC has its addresses or tags that it uses for running the program. The HMI has tags that can be used for internal programs and functions or they can be mapped to PLC tags. Many HMI's also have the ability to import the tags from the PLC and use them directly in the HMI. In the latter case you don't have to create a tag in the HMI and map it to a PLC tag or address. You just select it out of the list and go.

As for how they exchange the data it is pretty simple. If the HMI is set to read a tag value it just goes to the PLC, asks for the tag data and then displays it on the screen. If the HMI is set up to write data to a tag then it will go to the PLC and writes the data from the HMI into the tag value.

It does this via the native protocol for the PLC like DF1 for AB or Modbus RTU or ????. That is why when you are spec'ing out a HMI it is important to make sure it has the protocol to work with your PLC. Of course if you stay with the same brand of PLC and HMI you should be in good shape. But dont limit yourself either. For example: I like AB PLC's but love the Red Lion HMI's. Just about any HMI worth its salt will be able to communicate with just about every mainstream PLC these days.

Hope I helped more than I confused

 

[kwade]

I wasn't thinking of a particular brand or combo. just generally speaking. I may do a project here soon using a Automation direct PLC and C-MORE touchscreen.
I'm sure I can figure this out from the manuals, just need an overview of how that works..

Which AutomationDirect PLC?
I think that they all have some sort of TagDatabase Export facility.

Which CMore family?
I think that they all have a Tag Database Import/Export facility.
I don't have much experience with the CMoreMicro, so I won't comment on that family.

 

[adisharr]

For the Automation Direct PLC's (Click, Do-More, etc..) you can create names for addresses in the PLC and then export them to a special format (usually something like a .CSV file) that the C-more software can import. You can then assign buttons, indicators, etc.., to the imported addresses. You can also create additional tags in the C-more and reference memory areas in the PLC directly but it's usually faster to create them all in the PLC and then just export/import..

 

[Jeebs]

Single project or not, concept is mostly identical:

PLC: Server
HMI: Client

Client initiates communication and makes requests.
Requests are created in the HMI software.

In single project software packages, such as TIA portal from Siemens, you can browse the tags/items in the PLC and select the ones you want. The relevant parameters are automatically configured for the HMI.

Individual project software packages requires you to manually configure these parameters.
Setting up the connection path to the PLC.
Selecting which tags/items you want to use, thus configuring tag, name, address if applicable, etc.

Most HMI software packages allows import/export of tags, which makes it easier to configure using Excel.
Some of them allows you to browse the PLC program, either online or offline. Such as FTView Studio.

Some packages you create a list of tags in the HMI software which link to the tags in the PLC, which are then used in the HMI software on objects.
Other packages you link to the tags in the PLC directly from the object itself, thus no general tag list is available.

But all of these are just different implementations of the server-client structure.

 

[milmat1]

I am thinking of using the Direct Logics DL06-AR (have used it before with great results) And a 6" C-more touchscreen. This will be a stand alone machine so I will just use a serial connection between them...

Thanks everyone for helping explain this to me.