MELSEC Q Series to VB

[ahpua 0]

Hi Guys, I am relatively new to PLC term and understand that PLC is stands for programmable controller to control device motion by sequence etc. I have a request from customer that they need to count item processed using sensor with Mitsubishi MESLSEC Q Series PLC and send the output to LCD monitor. Sensor -> Input MESLSEC Q Series PLC -> MX Components?/OPC Server? -> VB/C -> LCD May I know in term of communication and program, what is need to bridge these integration? I heard about OPC server or MX Components to communicate and act as driver to PLC, could someone can share his/her ideas with me. Many thanks in advance for your advice/opinions/thought. I might having the wrong idea/concept please do no hesitate to correct me. Thanks. Regards, Pua

[Crossbow 297]

MX Component is a set of comm drivers as ActiveX controls you can use in Visual Basic of Visual C++. What's the LCD display? Does it perhaps have drivers to communicate with the Mitsubishi PLC directly?

[ahpua 0]

Hi Crossbow, Thanks for reply. What we need to achieve is quite straight forward as such acquiring MX components software suite might be a waste. Understand MX components of its rich functionality but I just need to create counter from PLC output and display it on a LCD monitor in manufacturing plant. I might just need to count no. of processed item against the daily target volume. Is MX components a must to bridge the integration? Maybe I should rephrase my earlier question like this. I need to construct HTML output on LCD screen/Monitor refreshing counter/no. based on input from PLC sensor device. What are the software/program I lacking of? Apologies as I purely from IT background on middleware/EAI and have not come across this scenario. Been reading OPC Server or I/O Server for communication to PLC but not sure I am looking for correct source/knowledge. What's the LCD display? Does it perhaps have drivers to communicate with the Mitsubishi PLC directly? LCD that I mean here are those LCD/Plasma TV display on manufacturing plant.

[kaare_t 155]

If you only need to display the data on 1 screen, maybe you should consider using a GOT terminal (which can communicate directly with the PLC). If this is not an option, I think you would prefer to use MX Components and not OPC Server. MX Components are ActiveX dll's which can be used directly in your developed software. OPC Servers however you will have to create a complete OPC Client in your software which would be a lot more work. A 3. option could be to install an Ethernet card on the PLC and simply develop the MC Protocol which are open and well documented.

[ahpua 0]

Hi Kaare_t, Thanks for your option suggestion to install an Ethernet card on the PLC and develop the MC Protocol. Am interested to know more about MC protocol, would I able to communicate with MC protocol in java socket programming? What are the common programming used to call MC protocol, any examples? Any advice is welcomed. Thanks. Edited 24 Nov 2010 by ahpua

[kaare_t 155]

Hi. Create an account at Mitsubishi to be able to log in and download manuals. You will need manual: SH(NA)-080008 (Q Corresponding MELSEC Communication Protocol). You can basically use any programming language you want as long as it supports basic TCP or UDP socket communication. The MC protocol is a binary (or ASCII but this is obsolete in my opinion) protocol. So as long as you are able to send/receive binary data via a socket then you are good to go.

[ahpua 0]

Hi Kaare_t, Thank you very much, this is the pointer i looking forward at least now I know what is the information I should start looking for. Really appreciate your advice and thanks again. regards, Edited 24 Nov 2010 by ahpua

[ahpua 0]

Hi Kaare_t, Stumble upon a pdf from mitsubishi 'Real Time Operating System C Controller' and in the doc it specifies about 'dedicated library' to programmable controllers, you have any ideas about these library? Are these only available on from VxWorks apps? Also, would like to check with you what are the pros n cons in using MC communication protocol vs Socket communication protocol for communication via Ethernet Port. Thanks. Regards,

[kaare_t 155]

I would think that 'dedicated library' is MX Components..... Not sure what you mean by "MC Protocol vs Socket Communication", would you please explain what you mean?? Normally I would say that a socket is what you create at the client side to communicate via TCP/IP to a server, while MC Protocol is a protocol, so in other words you create a socket and then you start sending the protocol... Please explain what you mean