Interfacing AB Micro830 with Computer using generic RS232

[ivanlch]

Hi,

I am working on a University project at the moment. The project scope is to implement a simple PID Program for a process tank and implement a SCADA/ HMI using Allen Bradley Micro830 PLC.

I know AB has its own HMI/ SCADA hardware. However, the aim of the project is to use software only.

So my questions are,

1) is it possible to implement a SCADA/ HMI on the computer with a generic RS232 cable + available SCADA/ HMI software or I need a RS232 cable that specifically made for Micro830?

2) how do I make my Micro830 communicate with the computer via RS232 cable? Are they able to communicate just by having the same modbus code? I am not sure how to do it.

3) how do I go about doing it? What are the available softwares? I thinking of using GE's CIMPLICTY but haven't got around to try it yet.

 

[ivanlch]

anyone?

 

[ivanlch]

Ok, lets say the cable works. How do I "bridge" my pc and PLC together? Is the cable going to do the job or the scada software is going to do the job? Or is it the program itself? Can you please enlighten me on this? How do I store and extract data from my plc? Eg, I am recording water level and flow rate. How do I extract it from my pc to put on my pc's screen? I am so new to this.

 

[Nigel Goodwin]

You need to find someone who's familiar with your PLC, or read the datasheet and instructions for it.

 

[cowboybob]

My experience is pretty much limited to direct serial comms with Toshiba and Siemens PLCs (seperately, of course), but I suspect the generalities cross over to others:

The Allen Bradley Micro830 PLC you intend to use allows configuration of the RS232 port to ASCII. This would allow you simply query the PLC for data, assuming you can put together a query string that the PLC will respond to (same goes for command strings). The cable needed might be as simple as gnd/tx/rx or it could also require a control line (RTS, CTS, etc.).

I started out by using a terminal emulator (on a old Epson POS), simply trying to get a relay to latch. Once I got that (which told me I had the packet properly configured) I was on my way.

That done, you could then program the PC to display that data captured however you wish. Or go further and develop a full blown GUI "control panel".

This may be somewhat dated advice.

 

[KeepItSimpleStupid]

I know nothing too, bit maybe enough to get you started.

One of the simplest interfaces is MODBUS. It can be serial or Ethernet. Now you need a MODBUS DLL for the PC.

LabVIEW is a generic language and you University might have a site license for it. Wonderware is a popular SCADA platform.

I picked this http://www.xdimax.com/sub20/sub20.html out of the air to somewhat give you an example. Serial MODBUS or whatever it's called is either RS485 or RS485 like. MODBUS also has a Master/Slave type of relationship.