HOW WE LINK SHARED VARIABLE WITH DEVICE ADRESSE (MODBUS SENSOR ADRESS ) IN I/O SERVER MODBUS

[soihiba]

I USE I/O SERVER MODBUS WITH SHARED VARIABLES TO COMMUNICATE WITH THREE DEVICES (TEMPERATURE DEVICE, PRESSURE DEVICE AND LEVEL DEVICE). EACH DEVICE HAS ITSELF  MODBUS ADRESS TO BE IDENTIFED IN I/O SERVER. THESE DEVICES SUPPORT THE MODBUS SERIAL.

1) HOW I CAN LINK EACH DEVICE WITH A SHARED VARIABLE USING DEVICE ADRESS ?

2) HOW I CAN USE DEVICE ADRESS TO IDENTTIFY THE DEVICE IN I/O SERVER ?

COULD YOU HELP ME ?

THANKS

[Coq_Rouge]

You should not eat or drink then working with your computer. The keys can get sticky like your Caps Lock key is now 😉

[Olivier_L · Accepted solution]

Hi,

You will find in attached file some slides explaining the different steps to create shared variables with Modbus I/O server.

You can also have a look to the demo on the website.

I hope this will help you to communicate with your devices.

Regards,

[Danigno]

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t06afre wrote:
You should not eat or drink then working with your computer. The keys can get sticky like your Caps Lock key is now 😉

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hahaha wow, that was the best polite and funny way of saying that I've ever seen!

Nice one t06afre

[soihiba]

THANK YOU VERY MUCH

[soihiba]

THANK YOU VERY MUCH FOR YOUR HELP

[Hsien]

Hi,

My system is to use LV8.6 as a modbus serial RTU server to control 15 ABB ACS550 drives as 15 slaves. I can be able to control the individual slave or two slaves by assigning the slave addresses; use the attached vi revised from NI's modbus liberary. Now, I try to use shared variables to control the slave now, but cannot read or control anything.  

I have followed Oliever's power point steps to setup the shared variables, but why does it not work?  Do I miss somthing?  Or does the variable dragged to the front pannel need to go through the processing in the MB Serial Master Query. vi to write to the MB and read from MB subvi as attached in the file? Thank you for any response.

[Olivier_L]

Hello,

You said that you can't control anything. What is happenning? Is there an error generated?

Then, the use of I/O server and shared variable is decorrelated from the use of MB Library. The MB Library permits to access the registers of your ModBus device, and the I/O server too, so you should not use both methods together.

And I can't have a look to your VI because of your sub-VIs that are not present. You should create a .zip file where every needed file for using your VI will be present.

I'm waiting from your news about possible errors appearing or the steps you did and the results you saw.

Thanks

[Hsien]

Oliever,

Thank you for the reply. 

There is no error generating on the screen.  Because I just draged the variable from the project explorer to a new vi's front panel, and run it and there is no error window showing up.  The arror indicator besides the variable only shows red when I want to run it.  I guess red means its not working. 

In the attached pic of Configure Modbus I/O server window, I wonder if the "Address" is the address of the slave device I assigned and want to control?  If I want to control more than one slave device, I create more Modbus device under the ?    For ex., I assigned my slave address as #6,  then I put 6 in the Address box? 

If I want to read thr holding register,  I just change the control variable to an indicator variable?  Why does it always show 0? 

Attached is the zip vi file (ACS550 main) works for the devices.  But I want to use shared variables instead of so much process in the vi. 

Thank you.

Jim

[Hsien]

The attached pic: