mscomm

[kool_j]

Hi
I want to use Visual Basic as a front end to talk an Hitachi EH150 PLC (yes an Hitachi PLC !!!). Can anyone point me in the right direction on how to set mscomm to do this. I to display the specific Words that has been read from the data memory.
Thanks

 

[Fred Raud]

9600 8,n,1

Fred Raud

 

[Steve Bailey]

What protocol does the Hitachi PLC use? Do you have the details of how to create a Data Read request?

 

[Steve Bailey]

koolj sent me this email.

Hi Steve, Thanks for the reply. The Hitachi EH150 uses the H Protocol, which is Hitachi own protocol. I can read the data from memory and aso know the address the data is store in memory. I can find out more about the H protocol if required. Hope this makes sense.

You'll need to find out how to compose a request for the data you want. This request will take the form of a string of ASCII characters. Let's call it Request$. In VB you'll execute a statement like:

MSComm1.Output = Request$

Following that, after some reasonable delay, you execute something like:

MSComm1.Input = Data$

Data$ will be some ASCII characters. There might be an acknowledgement from the PLC before the actual data. Then you extract the data from Data$

 

[ayman metwally]

kool_j,

If your problem is only in the VB code, You can find all the information you need about it in the www.MSDN.com

Search for "mscomm" and "serial communication" in Visual Basic section.

 

[sandeeppatil1980]

hi

hi
you need to add ms comm comp from activx lib,
then if use input (inputting data from device)& mscomm1.output for sending data , you can have seeting about baudrate , parity etc
in vb if your application is countionus polling based the you need a two timer to countious scan port
i think you are using a RS 232 for coummuncation
if you want to read reg in plcs then you have set control reg of plcs the start read/writting data to it

thanks
sandeep patil