OPC writing to PLC

[syd_b]

Hi, i have an Allen-Bradley PLC (slc 500) and I have connected to Labiew 8.5 through OPC server with RsLinx Gateway.

The question I have is, it´s posible to control an output(O0:0) or an input(I0:1) of the PLC through the OPC. I can write to a variable (N7:0,etc) but I want to control directly an output or an input of the PLC

If it´s possible, how can I do it.

Thanks.

[brijesh]

Hi,

So You Are able to write data in N 0:0 I think You are writing on Modbus address Is it ?

As I had connected Mitshubishi PLC to Ni OPC server Easily, Where We could directly read write onto their Register.

(Say D words (D100) as well as Boolean M Bit (M 100)).

So I am Sure you can do read write directly in Allen Bretly PLC.

That Is sure.

May be you might be selecting wrong driver.

Because, after selecting driver just create one Device and then create tag. In that tag whatever the Register terminology you use for the PLC will pop up while creating tags. Like in Mitshubishi we had D words, Boolean For M bit, Network Register were W and B Bit.

So I think Just check, u might be making mistake with driver selection.

Thank U so much for putting post.

Brijesh Patel

[syd_b]

Hi briejesh,

Thanks for your response but maybe I don´t explain well my question.

I can read and write to any address, I can read inputs but Can I write to a digital input though Labview instead of using a 24V DC in the digital input?

I can write to outputs but wen I write to it, It activates all the outputs. Can I write just to one output?

Thanks.